How to grow Cymbidium goeringii? Do these five things and it will keep blooming

Growing Techniques Jan 1, 1970 0 views

Cymbidium goeringii is one of the orchid species with the longest cultivation history among Chinese orchids. As the year draws to a close, many households display Cymbidium goeringii: first, it adds a scenic touch to the home; second, once it blooms, its fragrance is intense and fills the room with a delicate scent that can also welcome guests

Cymbidium goeringii grows under sparse woodland in mountainous areas and prefers semi-shaded, fairly humid environments. In ordinary home cultivation, poor management of light, humidity and temperature often leads to problems such as dry leaf tips and yellow leaves. Among orchid-growing proverbs there is "in spring do not take it out, in summer do not sun it, in autumn do not let it dry, in winter do not keep it wet", which is a highly condensed summary of Cymbidium goeringii care. Below, the key points of orchid care and management are explained one by one.

First, potting soil

The roots of Cymbidium goeringii are fleshy roots; they tolerate drought and fear waterlogging. It likes loose, fertile, well-drained, slightly acidic sandy loam. I personally like to use pine needle soil; pine needle soil is a leaf-mould soil rich in humus, loose and fertile, and slightly acidic, made by composting needle-like pine leaves such as those of masson pine and cedar. In earlier years, in pine forests on the mountains or mixed forests containing pines, the pine needle soil could reach a thickness of 60 cm, and wild Cymbidium goeringii was especially abundant there. In recent years, due to excessive digging, good pine needle soil is hard to find, but it can still be found on the big mountains. Also, under cedar trees that have been planted in green spaces for a long time, there will be more than 10 cm of pine needle soil. For Cymbidium goeringii, the requirements for growing medium are not high; use a half-and-half mix of leaf mould and sandy loam. In addition, alkaline soil must not be used, otherwise your Cymbidium goeringii will not agree to it!

Second, watering management

A floral proverb says "dry orchids, wet chrysanthemums"; the potting soil of Cymbidium goeringii should be eight parts dry and two parts moist; too wet and the roots rot. The principle of watering is "water when dry, stop when wet; if not dry, do not water". In March and April, during the leaf bud stage and flowering stage, water less; in May and June, water more; in autumn, when the climate is dry, spray the leaves more often to increase air humidity; in winter, when temperatures are low, reduce watering. Conditions are better now; when growing orchids in air-conditioned rooms, the air is relatively dry, so a humidifier can be used to increase humidity. It is best to use rainwater for watering; do not use tap water directly. Tap water must be left in the sun for 2-3 days before use. For potted Cymbidium goeringii, water around noon in spring and winter, and in the morning or evening in summer and autumn, avoiding watering or spraying at noon in summer. For watering, water more in summer and less in winter, and in spring and autumn generally just moderate amounts are fine. In short, follow one principle: do not water if not dry; when dry, water thoroughly.

Third, fertilisation management
Cymbidium goeringii does not tolerate strong fertiliser; it is best to "apply thin fertiliser frequently", and do not apply during the flowering period or dormancy period. During the growing season, apply a dilute cake fertiliser solution once every 15-20 days. If the water quality is alkaline, black alum (ferrous sulfate) can be added to make alum fertiliser water. The ratio of alum fertiliser water is black alum : cake fertiliser : water = 1:5:100. When fertilising, thin fertiliser and frequent application are required; the concentration must not be too high, otherwise fertiliser burn will occur and may even cause the death of Cymbidium goeringii, which would be a loss not worth the gain.

Fourth, light management

Cymbidium goeringii prefers a semi-shaded environment. If light is insufficient, the plant grows leggy and weak, flower buds do not differentiate, and it is not easy to bloom; if light is too strong, the leaves turn yellow and growth stops. Hence there is the saying, "The method of growing orchids: more sun makes the flowers good, more shade makes the leaves good... measured in tenths, seven-tenths shade and three-tenths open sky is sufficient." In winter the sunlight is weak, so full light can be accepted; in spring and autumn, shade moderately; in summer, shade heavily.

Fifth, temperature management

The most suitable temperature for the growth of Cymbidium goeringii is 18-28°C; the maximum should not exceed 35°C, and the minimum should not fall below 0°C. In winter, Cymbidium goeringii must undergo 3-5 weeks of vernalisation, that is, it must spend 3-5 weeks at a temperature of 0-10°C, otherwise the flowering quality will be poor. In northern regions, an enclosed balcony is quite suitable for winter vernalisation; if vernalisation is carried out in an air-conditioned room, it cannot proceed.

[The flower language of orchids]: indifferent to fame and fortune, elegant, beautiful, noble and virtuous, and virtuous.

Friends, as long as you do the above points, I believe you can see the Cymbidium goeringii you have carefully cultivated filling the air with fragrance. All right, friends who like growing orchids can study this.

Orchid growing methods: how to grow orchids best

Orchid growing methods

Choosing soil

For planting orchids, you can use black mountain soil, peat soil, garden soil, pine humus soil, moss, fern roots, bark chunks, etc. Cover the drainage holes at the bottom of the pot with tile pieces, then spread a layer of broken brick, tile and stone granules, with a thickness of one quarter of the pot depth, to enhance aeration and drainage, and then spread a layer of growing soil. Set the orchid upright and plant it, fill in growing soil, and cover the pseudobulbs. The soil should be firmed down, and leave 2 cm from the pot rim unfilled for ease of watering. After planting, water thoroughly and place it in a cool, shaded place. After half a month, move it to a sunny, ventilated environment for cultivation. To increase beauty and moisture retention, a layer of small white crushed stones can be spread on the pot surface.

Light and moisture

There are four prohibitions in orchid growing: namely "in spring do not take it out, in summer do not sun it, in autumn do not let it dry, in winter do not keep it wet". In spring, temperatures are still unstable, and taking it out of the room too early makes it susceptible to cold wind. It is relatively safe to take it out in early April. In summer, it should be placed under a shade frame, avoiding direct sunlight, and cultivated under diffused light. Autumn is the period when orchids sprout and send up flower spikes, so corresponding humidity should be maintained and dryness avoided. Orchid roots are fleshy; in winter dormancy the water requirement is not great, and the potting soil only needs to be slightly moist. Do not water excessively, so as to avoid root and leaf diseases.

Fertilising

Fertiliser should be thin, not concentrated: during the growing period, apply once every half month with rotted bean cake water or horse-hoof residue water. If an appropriate amount of potassium dihydrogen phosphate is added, the effect is even better. Do not fertilise in hot summer. When the temperature is too high (above 32°C), besides daily watering, spray water several more times. Slightly acidic water is preferable. Frequently spray and wash the leaf surface with clean water, which not only improves the growing environment of the potted orchid but also keeps the leaves clean and reduces the chance of pest and disease infection.

Pruning

During orchid cultivation, pruning must be carried out continuously. When old leaves turn yellow and withered, they should be cut off in time to facilitate ventilation, and some leaves whose tips have dried out should also be cut off. In particular, leaves harmed by pests and diseases must be removed in time to avoid contagion. When cutting off leaves with viral disease, the scissors used should not then be used to cut healthy leaves, in case the virus spreads. If the same pair of scissors is used, it must be disinfected.

After the flower buds of precious orchids emerge from the soil, if there are too many flower buds, the strong buds should be kept and the remaining thin, small flower buds removed; it is appropriate to keep 1-2 flower buds per pot. If there are too many flower buds, not only will the flowers of the current year not open well, but too much of the parent plant's nutrients will be consumed, affecting flowering the following year. Generally, orchids do not need their flower buds cut off.

The flowers of Cymbidium goeringii bloom for about half a month, after which the flowers need to be cut off; for summer orchids, when the last flower on the inflorescence has been open for a week, the inflorescence should also be cut off. Precious varieties should not be allowed to be pollinated and set seed, otherwise flowering the following year will be affected. If they are used for hybrid breeding, then they need extra careful cultivation so that the fruit becomes plump and ripe.

Pest and disease protection

Orchids are prone to scale insects, which can be treated by spraying with dichlorvos emulsifiable concentrate at 1000 times dilution. When whiteflies cause harm, spray with deltamethrin at 2000 times dilution to kill them. Orchid roots have a sweet taste and easily attract ants, which can be lured and killed with meat bones. Orchids are prone to anthracnose fungi and black spot fungi. After disease occurs, promptly remove and burn diseased leaves, widen the spacing between pots and plants, and improve ventilation and light conditions. Reduce water spraying, control humidity, and combine with carbendazim for prevention and control. Sterilisation treatment should be carried out (exposure to the blazing sun is sufficient) to prevent disease occurrence.

Orchids are most prone to southern blight in rainy, high-temperature seasons, which can be prevented by spraying with thiophanate at 800 times dilution or Bordeaux mixture. If the disease is severe, thiophanate at 500-750 times dilution can be used, spraying once every 7-10 days. Among pests, scale insects occur most often; this insect attaches to the base of the leaves, and if scale insects are found, they should be removed in time. To avoid scale insect infestation, starting in April, "1059" at 2000 times dilution can be used for control.

In order to suppress the occurrence of orchid diseases, in addition to appropriately controlling the dryness and moisture of the potting soil at ordinary times, when choosing flower pots, clay pots should be used as much as possible and glazed pots used less. In particular, newly dug orchids from the mountains that grow poorly must be planted in clay pots. Doing so makes the potting soil dry easily, which can promote orchid growth and reduce disease occurrence.

Requirements for orchid growing medium

Wild orchids grow on shaded, ventilated mountain slopes where water does not accumulate, so the growing medium is required to be aerated, soft, well drained, and slightly acidic. For orchids, crushed stone soil, red soil brick rubble, and also soil with clumps of weeds that has been roasted over fire into crushed roasted soil are used by some people. The above several growing media all conform to the characteristics of aeration, water permeability and slight acidity, and are rich in phosphorus and potassium fertiliser, so they can be used as orchid growing medium, but nitrogen fertiliser should be supplemented appropriately. In recent years, with the introduction of advanced orchid-growing methods from Hong Kong, China, Taiwan, China and abroad, indoor orchid growing has been greatly promoted. Therefore, the use of sphagnum moss, perlite, volcanic ejecta, granular brick chunks, granular senju soil, granular peat, etc. has become an ideal growing medium. Their greatest advantage is that they facilitate water management and aeration.

Orchid requirements for air

Orchids like circulating, unpolluted air. If the air does not circulate, bacteria and viruses will adhere to the leaf surface, harming orchid growth. Orchid-growing sites should be far from coal gas, oil fumes, and places with flying dust. Oil fumes and dust adhering to the leaf surface will block leaf respiration and affect photosynthesis. Air circulation can improve the temperature of the orchid growing environment and help maintain the most suitable growing humidity. Air circulation can promptly replenish the carbon dioxide consumed by photosynthesis in the orchid growing environment and keep its content stable, thereby improving photosynthetic efficiency.

Therefore, when opening up an orchid-growing site, one should artificially avoid places with poor air circulation, coal gas, oil fumes, and flying dust, and choose a site facing south with relatively tall buildings or large trees and woods to the northwest, and open space in front. These places have fresh, circulating air and are extremely favourable for orchid growth.

Orchid requirements for temperature

Temperature is the lifeblood of biological survival and development. For living orchids, their survival and development are closely linked to temperature. When the temperature is suitable, they grow luxuriantly; when the temperature is too high, their growth stagnates and they may even die young from the harm of stifling heat; when the temperature is low, they enter a dormant state, and when it is too low, they wither and die from cold damage.

(1) The optimal growing temperature for orchid rooting, sprouting and normal growth is 20-28°C; below 20°C, although they can grow, growth is slow; above 28°C, although growth is rapid, they are also easily forced into a dormant state because the temperature is too high. Therefore, whenever the temperature is above 32°C, measures should be taken to increase shading density, increase ventilation and raise air humidity, so as to ensure ecological conditions for rapid orchid growth.

(2) Suitable temperature for dormancy: the suitable temperature during the orchid dormancy period is 10-16°C during the day and 5-10°C at night. However, the suitable temperature during the dormancy period of Cymbidium goeringii should be controlled below 10°C and above 3°C, so that it can pass through the vernalisation stage and ensure normal flowering. If the temperature during dormancy is too high, although dormancy can be broken, the germination rate increased, and the number of germinations increased, there are drawbacks such as easy premature ageing and shortened lifespan.

(3) The lowest temperatures orchids can tolerate: Cymbidium goeringii is -4°C, Cymbidium ensifolium is -2°C, and Cymbidium sinense is 2°C.

According to China's geographical location, it is difficult for all parts of the country to have ideal temperatures year-round, and temperatures vary from place to place. Therefore, according to the temperature needs of orchids, necessary artificial regulation should be carried out to create temperatures suitable for orchid growth and dormancy. When the orchid-growing site has temperatures unfavourable to orchid growth, and lower temperatures are encountered, artificial heating is needed. If the orchid site is small, air conditioners, electric heaters, radiators, etc. can be used for heating. If the orchid site is large, heating equipment can be installed, using heating to raise the temperature. In summer, when the temperature of the orchid site is over 30 degrees, paying attention to ventilation generally means there is not much problem, and orchids can also resist a certain degree of high temperature. If the temperature is especially high, then artificial cooling measures must be taken, using air conditioners, electric fans, exhaust fans, spraying water on the ground, placing water in basins, cold air, etc. to lower the temperature. (Sanlian Reading

To make orchids grow well and bloom abundantly and gorgeously, fertilising is extremely important in the process of orchid cultivation. Orchids like light feeding; when fertilising, it is better to be thin than concentrated. During the vigorous growth period of orchids, more fertiliser should be applied; during dormancy or weak growth periods, no fertiliser may be applied. The most important thing in fertilising orchids is not to be impatient for quick results. If fertiliser is applied excessively, it will burn roots and leaves and cause irreparable loss. Modern orchid growing mostly emphasises foliar feeding, that is, spraying fertiliser on the leaves. Thin fertiliser can also be poured at the roots. Dilute fertiliser should be applied frequently. During the seedling stage of orchids, nitrogen fertiliser can be the main type, to promote rapid growth of orchid seedlings, producing shoots and roots; when the new shoots have grown to about 5-6 cm, phosphorus and potassium fertilisers can be the main type, to promote stout and strong orchid shoot heads. This improves the immunity of orchid seedlings against diseases and pests. During the vigorous growth period of large seedlings and strong plants, nitrogen fertiliser should be applied frequently, once a week. For plants being rejuvenated, the frequency should be appropriately reduced, once every half month or a little longer. As for weak plants, rootless plants, and leafless pseudobulbs, they absolutely must be grown plainly without fertiliser. Otherwise, haste makes waste and they will suffer harm instead. Fertilising should be done on cloudy days or in the evening when the temperature has dropped, and water should be applied again the next morning, commonly called returning water. This can wash away residual fertiliser and benefit orchid growth.

Orchid requirements for water

Controlling water is the most fundamental condition for growing orchids well. Orchid leaves are relatively thick and protected by a cuticle on the surface, so orchid leaves do not consume large amounts of water. The pseudobulbs and fleshy roots of orchids can store a certain amount of nutrients and water, so they are fairly drought-tolerant. Except during the root-producing and sprouting stages and the rapid growth period, when more water is needed, at other times they consume relatively little water. If there is too much water, causing waterlogging in the soil and blocking root respiration, the roots rot easily. Too much water can also cause the cell walls of orchid leaves to become water-filled, opening the stomata on the leaf surface, resulting in diluted nutrients and further causing weak tissues, poor growth, and disease. Orchids "like rain but fear flooding, like moisture but fear wetness". Because air humidity differs in spring, summer, autumn and winter, and orchid growth rates differ, the water requirements also differ.

At the same time, the bodies of orchids and cymbidiums are on the acidic side. Because the vast majority of orchid and cymbidium flowers are based on green tones, the water used should meet the slightly acidic requirement. Generally, a pH value of 5.5 to 6 is best. Water with a high pH value cannot be used for growing orchids. You should have a clear idea of the pH of the water. If the alkalinity is too high, you can put a little ferrous sulfate, nitrite or rice vinegar into the water, and after it meets the requirement, then pour it at the roots or spray the orchids. Water that is too acidic also cannot be used; after watering, it is also harmful to orchid growth.

Generally speaking, for watering orchids, water once a day in summer, once every 3-4 days in spring and autumn, and once every 5-7 days in winter. However, orchid watering cannot be generalised; with different pots, different growing media, different sites, different seasons and different regions, the strength of water absorption by orchid plants differs, so one cannot mechanically apply a fixed rule; watering should be based on the actual situation. In summer, watering should be done at the lowest temperature; in spring and autumn, watering in the morning is better; in winter, watering can be done at noon. The temperature difference between the water temperature and the air in the orchid-growing site should not be too great. If necessary, add a little hot water to cold water to raise the water temperature; this is beneficial to orchid growth.

How to water orchids

Water is the source of life for orchids

First, water is an important component of orchid plant protoplasm. The water content of orchid plant protoplasm is generally above 80%. If the water content decreases, life activities are affected. If the protoplasm loses too much water, it will cause the destruction of the protoplasm and lead to plant death.

Second, water is a raw material in the metabolic process of orchid plants. The assimilation and dissimilation processes in orchid plants all require the participation of water molecules, such as photosynthesis, respiration, hydrolysis reactions, etc.

Third, water is the medium of the metabolic process of orchid plants. The nutrient elements in the growing medium can only be absorbed by orchid roots after dissolving in water, and various metabolic products must also be transported with water to all parts of the orchid plant.

Fourth, water can keep orchid plants in their inherent form. Only when the cells of orchid plants contain a large amount of water can the cells expand, the plant stand upright, and light reception and gas exchange be facilitated. Once an orchid plant loses water, it will wilt.

Fifth, water can regulate the body temperature of orchid plants. Water has a very high heat of vaporisation and specific heat, and also relatively high thermal conductivity, which helps orchid plants maintain body temperature and dissipate heat. One important function of watering orchids is to regulate the body temperature of orchid plants.

In short, water is the source of life for orchids and the foundation of orchid growth. Appropriately meeting the water needs of orchid plants is the most important condition for orchid growth.

Two ways to supply water to orchids

There are two ways to supply the water needed by orchid plants: one is absorption of water from the growing medium by the roots, transported to the whole plant through the vascular system; the other is absorption of water from the air by orchid leaves, to supply what is needed for orchid plant metabolism. Understanding this principle means knowing how to supply water to orchid plants.

Methods of watering orchids

The methods of supplying water to orchid roots are: pouring, sprinkling (drenching), and soaking. "Pouring" means using a watering can to pour water along the edge of the pot. The advantage of this method is that water will not get into the leaf centre; the disadvantage is that watering is slow and difficult to make thorough, and repeated pouring is needed to achieve a thorough watering effect. "Sprinkling" means using a spray can or shower head to sprinkle water, wetting the entire orchid-growing environment, letting water seep from the soil surface to the orchid roots and moisten the orchid pot. The advantage of this method is that the water can thoroughly wet the entire orchid pot; the disadvantage is that water easily splashes into the leaf centre, so it must be used carefully, otherwise the centre will rot. "Soaking" means immersing three quarters of the orchid pot together with the growing medium into water. The advantage is that the water can soak through; the disadvantage is that it easily spreads bacteria and is labour- and time-consuming. Expert orchid growers often combine these three methods, with very ideal results.

The methods of supplying water to orchid leaves are: spraying and humidifying. "Spraying" means using a sprayer to spray out fine mist that directly settles on the orchid leaves, allowing the orchid leaves to absorb it through the stomata. "Humidifying" means increasing air humidity for the orchid leaves to absorb. There are also several humidifying methods: first, using a humidifier to create mist and increase spatial humidity; second, increasing water surface area by placing more water basins under the orchid stand, relying on water evaporation to increase spatial humidity; third, artificially simulating rainfall, splashing up water mist to increase air humidity; in addition, some also use an oxygen pump placed in a water basin to help volatilise water vapour, and so on.

Water quality for watering orchids

Wild orchids grow relying on rainwater, so the water used for cultivating orchids should be natural and pure, preferably clean and slightly acidic (pH value around 5.5). Usually rainwater is best, river water is excellent, tap water is next, and well water must not be used. "Rainwater" contains many and complete fertiliser components, among which spring rain is especially good, thunder showers are relatively better, autumn rain is next; artificial rain must not be used, and acid rain is harmful. "River water and pond water" are formed by collected rainwater and are beneficial to orchids, but river water polluted by industrial wastewater must not be used; "tap water", if taken from underground, must not be used; if taken from a river, its essence is still rainwater, but after processing by the waterworks, disinfecting and clarifying agents are present, which are harmful to orchids and cannot be applied directly. There are two solutions: first, fill several vats with tap water, expose them to the open air and sun, store them for many days, and use them in rotation; second, put in a small amount of fruit peel such as orange peel, apple peel, etc., store for one or two days, and then use; this has a practical effect on changing the water quality of tap water. "Well water" belongs to groundwater: first, its temperature is low, and sudden watering is unfavourable to orchid growth; second, it is on the alkaline side, and well water contains more calcium and magnesium salts, and frequent watering is harmful to orchids.

Timing of watering orchids

Orchids "like moisture but fear wetness, like dryness but fear parchedness". This saying of the ancients is very scientifically reasonable. "Wetness", "moisture", "dryness" and "parchedness" differ in degree. Excessive moisture is wetness; "wetness" means too much water, which will suffocate orchid roots and cause them to rot and die; excessive dryness is parchedness; "parchedness" means too little water, which will cause orchid plants to wilt, growth to be checked, and even drying up to death; while "dryness" and "moisture" mean moderate water, which is the state that orchids like for growth. To understand the key issues of "dryness" and "moisture", one must observe and experience carefully in practice and gradually accumulate experience before one can truly master it. There is no quick method; it takes no less than "three years of skill". Generally speaking, when the growing medium on the pot surface is dry but not parched, and the hole at the bottom of the pot is moist but not wet, that is the best time to water orchid plants. There is no need to wait until the potting soil is completely dry before watering, otherwise it will have an adverse effect on orchid growth and development.

Watering orchids should be based on natural factors

When watering orchids, different water management measures should be made according to various natural factors affecting the transpiration of orchid plants, such as humidity, temperature, light, wind, season, and weather.

First, look at humidity. If the air humidity is relatively low and transpiration is strong, water more; conversely, if the air humidity is high or even saturated and transpiration almost stops, water less or even do not water.

Second, look at temperature. When the temperature is high, transpiration accelerates and the water requirement is large, so the watering frequency should also increase correspondingly; conversely, when the temperature is low, water molecule activity is slow and diffusion is weak, so the water requirement is small.

Third, look at light. When light is strong, transpiration accelerates, speeding up water molecule diffusion, and the water requirement is greater; conversely, the water requirement is smaller. Therefore, with different light and different shading degrees, water management also differs: those receiving more sun should be watered more, and those facing away from the sun should be watered less.

Fourth, look at wind. When the wind is strong, water evaporates quickly; when the wind is weak, water evaporates slowly; dry southwest wind will enhance evaporation, while on the contrary humid southeast wind will cause transpiration to weaken relatively; orchid pots placed at a wind inlet receive more wind and evaporate water quickly, while orchid pots in sheltered places receive less wind and evaporate water slowly.

Fifth, look at the season. Different seasons have different temperatures, humidity and light, and the transpiration of orchid plants also differs greatly. In the hot, dry summer, water more; in the plum rain season, water less or not at all; in the low-temperature, cold, overcast winter, do not water; in early spring when the temperature is relatively low, water less; in late spring when the climate is mild and it is the sprouting period, water more; in the dry autumn, water more.

Sixth, look at the weather. Weather in the natural world is changeable; different weather has different light, temperature and humidity, and the transpiration of orchid plants also varies greatly. The basic practice is: water more on sunny days, water less on cloudy days, do not water much when rain is imminent, and do not water on rainy (snowy) days.

Accordingly, it is very difficult to have an accurate and unified management method for watering orchid plants. The saying "water once every few days" lacks a scientific basis.

Precautions for watering orchids

First, pay attention to water temperature. In winter, do not water with cold water; the water temperature should be close to room temperature, preferably 8-10°C. In summer, do not water with hot water. If water is stored in a water tower, beware of water temperature being too high and harming orchid plants and roots; the water temperature must not exceed 25-28°C, and cold water must not be used suddenly for watering, so as not to harm orchid plants.

Second, pay attention to humidity. When air humidity is too high, reaching 90-100 degrees, absolutely do not water or spray. During the day, humidity of 70-90 is suitable. Too much humidity will weaken the root's role in absorbing water, affect the number of roots produced, and cause orchid plants to lose their driving force.

Third, pay attention to protecting new shoots. During the new shoot splitting period, it is suitable to water at the roots and to minimise sprinkling and spraying, otherwise water poured into the leaf centre causes waterlogging and rotting, resulting in losses.

Fourth, be careful not to give half-hearted watering. Some people mistakenly believe that orchids cannot be watered much, so they do not dare to water and often give half-hearted watering, leaving the potting medium wet on top and dry below for a long time, causing the roots to dry up and wither from lack of water.

Fifth, be careful to water less with standing water. If water is stored in a water tower for too long, water molecules form chain-like bodies, and the longer the time, the harder they are to break apart, making it difficult for them to participate in metabolic activities and unfavourable for absorption by orchid plants.

Sixth, be careful to water with "soul-returning water". After fertilising in the evening, orchid plants absorb through a whole night and can effectively absorb most of the nutrients. At this time they most need water, just as people need tea after a meal, so the next morning "soul-returning water" needs to be applied. It has two functions: first, to wash off fertiliser liquid splashed onto the leaves; second, to wash away residual fertiliser in the pot to prevent fertiliser burn.

Seventh, be careful not to water too frequently. Orchids have a very large tolerance for water and are relatively drought-tolerant plants, so being a little dry has little effect. On the contrary, being wet is not acceptable; waterlogging for 24 hours will cause suffocation. In daily cultivation, the vast majority of people love orchids too much and water too frequently, causing root rot and even plant death.

Eighth, be careful of "acid rain". If using rainwater, there are two kinds that cannot be used. First, acid rainwater cannot be used to water orchids. So-called "acid rain" is formed when sulfides, fluorides and other acidic substances suspended in the air fall with rainfall. This water absolutely must not be used to water orchids. Second, water from artificial rainfall cannot be used; rain shells contain chemical substances, and these substances dissolve in rainwater; using it to water orchids will also corrode orchid roots.

Ninth, be careful not to spray water arbitrarily. "Spraying water" is necessary; besides supplementing water, it can also keep orchid leaves fresh, which is beneficial to orchid leaf respiration and photosynthesis. However, water cannot be sprayed arbitrarily: do not spray under strong sunlight; do not spray in high-temperature weather; spray less when there is no wind and it is difficult to dry; do not spray water containing impurities; do not spray when rain makes humidity too high, and so on.

How can orchids be grown so that they bloom?

1. Site

The place where orchids are placed is very important; it directly affects the growth and development of orchids. Orchids are generally placed in the open in spring, summer and autumn (in summer, placed in a shaded open area), and indoors in winter. Outdoors, it is best to have open space all around and moist air. Indoors, there should be sufficient light, preferably facing south. In this way, orchid growth is favoured. Orchid pots are best placed on wooden stands or tables, not on the ground.

2. Shading

Most orchids belong to semi-shade plants, and most species fear direct sunlight, so appropriate shading is needed. In early to mid-April, orchids can receive more sunlight to promote growth. After late April, appropriate shading is needed. Among summer orchids and autumn orchids, varieties with upright leaves are best placed on the south side of a shaded area so that they receive appropriately more sunlight; for drooping-leaf autumn orchids and Cymbidium goeringii, receiving two hours of light per day is best. From the beginning of June to September, shading should be started earlier each day; for example, with reed curtains, dense curtains or two layers of sparse curtains can be used. After October, the weather turns cooler and sunlight is weaker, so shading can be delayed, but around noon attention should still be paid to doing the shading work well.

3. Rain protection

Orchids can be exposed to light rain, but must be protected from plum rain, showers, or continuous rain. In the plum rain season, rain protection work must be done especially well. From late June to mid-September, there are often showers. If the rain lasts a short time and the rainfall is small, more water should be given in the evening to let the hot air in the pot escape; otherwise orchids will be harmed and may even rot at the roots and die. If a shower is followed by sunshine, shading should be done in time, so as to prevent heat rising from the ground from affecting orchid growth.

In rainy seasons, which coincide with the stage when orchids send up leaf buds, if the potting soil is too warm it will cause poor leaf bud growth or invite disease. At this time, a small amount of plant ash can be scattered to regulate the humidity of the potting soil.

4. Watering

A floral proverb says: "dry orchids, wet chrysanthemums"; there is some truth in this. Generally speaking, orchids are best kept eight parts dry and two parts moist. If too wet, the flowers easily rot at the roots and die. The principle of watering should be: water when dry, stop when wet, and appropriately lean dry. In specific practice, generally note: during the growing period (from May to the end of June), water appropriately more; during the leaf bud emergence period (about March-April) and flowering period (about March-April), water appropriately less; during dormancy (winter), water even less or not at all. If the flower pot is large and the orchid plant is small, water less; if the pot is small and the plant is large, water more. In hot, dry weather, water appropriately more; in cool, damp conditions (such as the plum rain season, etc.), water less or not at all. For orchids newly dug from the mountains, if the root system is sparse or many roots are broken, water less and keep the potting soil a little dry; this will prevent root rot and help send up new leaves.

How to grow orchids in summer

Watering methods:Orchids like loam that is dry but not parched. In summer, water evaporates relatively quickly and the soil dries easily. The usual watering method is to water once in the morning, with a large amount of water, which we call thorough watering, that is, making all the soil in the pot moist. After noon, depending on the degree of dryness or moisture of the soil, decide when to water; when the surface soil appears slightly dry and hard, water once, with a small amount of water, just moistening the surface layer.

Fertilising methods:The fertilising method for potted orchids is to fertilise less or even not at all after the temperature exceeds 25 degrees, because when the temperature is too high, orchid transpiration strengthens and water is lost too quickly; if fertiliser is applied at this time, it easily causes the plant to lack water and wither. If you think fertilising at high temperature is very necessary, try to use leaf fertiliser. If you use liquid fertiliser, you can reduce the concentration; generally fertilise once every twenty-five days, with the concentration below one twentieth.

Temperature control:The suitable temperature for orchids is 25-30°C. If the temperature is too high or too low, orchids will stop growing. In summer, when the temperature is too high, if orchids are placed outdoors, direct sunlight will make them listless, so you can set up a sunshade net to prevent excessive temperature, maintain ventilation, and spray water mist at any time to cool them down.

Control of scale insects and aphids:In summer, if orchids have scale insects, they can be seen with the naked eye, and you can just catch them by hand or with tweezers. Aphids are relatively small, and are generally treated by scattering pesticide; there are many pesticides that kill aphids. My mother's method is to use soap powder mixed with 500 times water as an insecticide, and after spraying, spray clean water again 12 hours later. Continuous spraying for 5 days is enough.

Control of root rot:Orchids like soil that is dry but not parched, so overly wet soil will cause root hypoxia, turning aerobic respiration into anaerobic respiration and producing a large amount of alcohol, causing the roots to rot. The way to prevent root rot is to frequently turn the soil to ensure the amount of air in the soil, and not to water too much; several small waterings are best.

Watering methods

Orchids like loam that is dry but not parched. In summer, water evaporates relatively quickly and the soil dries easily. The usual watering method is to water once in the morning, with a large amount of water, which we call thorough watering, that is, making all the soil in the pot moist. After noon, depending on the degree of dryness or moisture of the soil, decide when to water; when the surface soil appears slightly dry and hard, water once, with a small amount of water, just moistening the surface layer.

Fertilising methods

The fertilising method for potted orchids is to fertilise less or even not at all after the temperature exceeds 25 degrees, because when the temperature is too high, orchid transpiration strengthens and water is lost too quickly; if fertiliser is applied at this time, it easily causes the plant to lack water and wither. If you think fertilising at high temperature is very necessary, try to use leaf fertiliser. If you use liquid fertiliser, you can reduce the concentration; generally fertilise once every twenty-five days, with the concentration below one twentieth.

Temperature control: The suitable temperature for orchids is 25-30°C. If the temperature is too high or too low, orchids will stop growing. In summer, when the temperature is too high, if orchids are placed outdoors, direct sunlight will make them listless, so you can set up a sunshade net to prevent excessive temperature, maintain ventilation, and spray water mist at any time to cool them down.

Control of scale insects and aphids

In summer, if orchids have scale insects, they can be seen with the naked eye, and you can just catch them by hand or with tweezers. Aphids are relatively small, and are generally treated by scattering pesticide; there are many pesticides that kill aphids. My mother's method is to use soap powder mixed with 500 times water as an insecticide, and after spraying, spray clean water again 12 hours later. Continuous spraying for 5 days is enough.

Control of root rot

Orchids like soil that is dry but not parched, so overly wet soil will cause root hypoxia, turning aerobic respiration into anaerobic respiration and producing a large amount of alcohol, causing the roots to rot. The way to prevent root rot is to frequently turn the soil to ensure the amount of air in the soil, and not to water too much; several small waterings are best.

Requirements for growing medium

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The complete guide to orchid growing and cultivation techniques

"Three parts planting, seven parts caring" - this is the ancients' experience in growing orchids. The quality of care determines whether orchids flourish and whether they can bloom, so it makes sense that the predecessors attached great importance to this. Below is a specific introduction to the methods of caring for and managing orchids.

I. Location

The location where orchids are placed is very important, as it directly affects the growth and development of the orchids. Generally, orchids are placed outdoors in spring, summer, and autumn (in summer, placed in a shaded spot outdoors), and indoors in winter. Outdoors, it is best to have open space on all sides and humid air. Indoors, there should be plenty of light, preferably facing south. This is beneficial for orchid growth. Orchid pots are best placed on wooden stands or tables, not on the ground.

II. Shading

Orchids mostly belong to semi-shade plants, and most species are afraid of direct sunlight, so they need appropriate shading. In early to mid-April, orchids can be given more sunlight to promote growth. After late April, appropriate shading is needed. For summer orchids and autumn orchids with upright leaves, it is best to place them in a shaded spot facing south so they receive appropriately more sunlight; for autumn orchids and spring orchids with drooping leaves, two hours of light per day is best. From June to September, shading should be started earlier each day; if using reed blinds, use dense blinds or two layers of sparse blinds. After October, when the weather turns cooler and sunlight is weaker, shading can be delayed, but around noon, shading work still needs attention.

III. Rain Protection

Orchids can tolerate light rain, but must be protected from plum rain, showers, or continuous rain. During the plum rain season, rain protection work must be especially well done. From late June to mid-September, there are often showers. If the rain duration is short and the rainfall is light, more watering should be done in the evening to let the heat inside the pot escape; otherwise, the orchids will be damaged, or even root rot and die. If a shower is followed by sunshine, shade must be provided promptly to prevent ground heat from rising and affecting orchid growth. In rainy seasons, which coincide with the stage when orchids are sprouting leaf buds, if the potting soil is too warm, it will cause poor leaf bud growth or invite disease. At this time, a small amount of plant ash can be sprinkled to regulate the moisture of the potting soil.

IV. Watering

There is a floral proverb: "Dry orchids, wet chrysanthemums," and this saying has some truth to it. Generally speaking, for orchids, eight parts dry and two parts wet is best. If too wet, the flowers are prone to root rot and death. The principle of watering should be: water when dry, stop when wet, and appropriately lean toward dry. In specific practice, generally note the following: during the growth period (May to the end of June), water appropriately more; during the leaf bud sprouting stage (about March to April) and the flowering period (about March to April), water appropriately less; during the dormant period (winter), water even less or not at all. If the pot is large and the orchid plant is small, water less; if the pot is small and the plant is large, water more. In hot and dry weather, water appropriately more; in cool and humid conditions (such as the plum rain season), water less or not at all. For orchids newly dug from the mountains, if the root system is sparse or many roots are broken, water less to keep the potting soil a bit dry; this prevents root rot and helps new leaves sprout. The ancients' experience that "do not let them dry in autumn, do not keep them wet in winter" is a very good summary of how to water spring orchids and summer orchids. However, in some northern regions, because the climate in winter and early spring is too dry, orchids should not be allowed to become too dry either. Watering time: in summer and autumn, watering after sunset is best so the orchid leaf surfaces dry before nightfall; watering in the early morning is also acceptable; in winter and spring, watering around sunrise is best. Do not suddenly water with cold water after scorching sun exposure, to avoid lowering soil temperature, affecting root water absorption, and disturbing physiological balance. The amount of water should not be too large, to help suppress the occurrence of disease.

Watering method: Water should be poured in from the edge of the pot, and must not be poured into the flower buds, to avoid causing rot.

Predecessors had very good summarized experience on watering orchids. For example, Yu Zhao in "Record of Orchid Cultivation in the Capital" proposed different watering methods according to the twenty-four solar terms within a year. The following is excerpted for reference. But two points need attention: first, "Record of Orchid Cultivation in the Capital" uses Beijing's climate as the standard; second, the months in the text refer to the lunar calendar rather than the Gregorian calendar, for example, "the first month" is actually February in the Gregorian calendar.

1. Start of Spring, Rain Water: Spring orchids have already flowered, so the soil should not be too dry; slightly moisten along the edge of the pot; if the autumn orchid pot has not dried to the bottom, do not water.

2. Awakening of Insects: When the spring orchid pot has dried halfway (dry on top, firm below), it can be moistened, but not much; autumn orchids same as above.

3. Spring Equinox: Spring orchids have finished flowering and should avoid dampness; when the pot is half dry, it can be moistened.

4. Clear and Bright, Grain Rain: Do not let the potting soil become too dry; moisten with water every 5 days.

5. Start of Summer: Orchids begin to be brought out of the room; it is suitable to water thoroughly once.

6. Lesser Fullness: Do not let the potting soil become too dry or too wet. If spots appear on the leaves, it is too wet; if the tips of new buds wither, it is too dry. Water one sheng (about one dry teacup) every 4 days, so that the lower 2/3 of the potting soil from bottom to top is moist.

7. Grain in Ear: The climate is dry, so pay even more attention to avoiding excessive dryness or wetness.

8. Summer Solstice: The potting soil must not be too dry. If heavy rain occurs, it can only be endured for one day; if there are continuous overcast and rainy days, the pot needs to be moved to a ventilated place.

9. Lesser Heat: At this time the air is too humid, so the potting soil must not be too wet; the pot should be placed in a ventilated place. If it is hot and dry with little rain, water one sheng every 2 days. After heavy rain or one heavy wetting, you must wait until 2/3 of the potting soil has dried; otherwise, it is not suitable to water again.

10. Greater Heat: The potting soil easily dries all the way through, so note that each day only one heavy rain or one heavy wetting is suitable.

11. Start of Autumn: Orchids need water at this time; water 2 sheng every 3 days, and it is suitable to provide wind protection.

12. End of Heat: Water once every 5 days; except during continuous hazy rain, they can be allowed to receive rain and dew.

13. White Dew: Autumn orchids need frequent watering even more than spring orchids, but after being wet, they must dry greatly before they can be wet again.

14. Autumn Equinox: If autumn orchids have already produced flowers, water slightly less; if they have not produced flowers, water slightly more.

15. Cold Dew: Autumn orchids should be watered thoroughly; spring orchids should not be watered thoroughly but should be moistened.

16. Frost Descent: Orchids should be brought indoors; watering time changes to midday, and after watering they need to be placed in midday sun for 1-2 hours.

17. Start of Winter: Only moistening with water is suitable, about half a sheng every 5 days.

18. Lesser Snow: The flower room should avoid warmth and should not be too wet. If too damp, it can cause root rot, scarred leaves, and even withering. If the pot has not dried to the bottom, only slightly moisten the soil surface.

19. Greater Snow: Autumn orchids do not need water; spring orchids should be slightly moistened.

20. Winter Solstice: Neither should be irrigated.

21. Lesser Cold: Watering is taboo for both.

22. Greater Cold: Autumn orchids still do not need water; spring orchids can be slightly moistened with water.

V. Fertilizing

Whether to fertilize orchids should be decided based on the orchids' growth condition. Those growing luxuriantly and without disease can be fertilized; those growing poorly should not be fertilized or should be fertilized only lightly. For orchids newly dug from the mountains, before new roots have developed, fertilizing is strictly forbidden; they need 1-2 years of cultivation, and only when new roots are vigorous can they be fertilized; otherwise, they are prone to withering and dying.

Generally speaking, in June-July, when orchid leaf buds have extended to about 1.5 cm, 1-2 applications of thin, fully rotted liquid fertilizer can be given (chemical fertilizers are not suitable), but fertilizing is not suitable in high-temperature seasons. In August-September, apply 1-2 more applications of rotted, thin liquid fertilizer. For plain-hearted orchid varieties, 1-2 applications of plant ash extract can be used, with very good results. Fertilizing in the evening is best, and the next morning water once with clear water.

A relatively simple way to determine whether orchids need fertilizing is to look at the depth of leaf color. If the leaves appear yellow and thin, it is a lack of fertilizer and topdressing should be applied; if the leaves appear dark and the leaf tips are scorched, it is excessive fertilizing and fertilizing should be stopped.

For fertilizer, the various methods introduced above can be used to make homemade fertilizer. When applying these fertilizers, they need to be diluted with 8-9 times water, and must not be too concentrated. When fertilizing, apply it to the root zone of the plant, and never apply it to the leaf surface. The main fertilizing times and dates for orchids: Times Date Category First time Second time Third time Fourth time Remarks

Spring orchid type: Late June, Mid-July, Mid-August, Early September. The fourth time should be especially thin.

Summer orchid type: Late June, Mid-July, Mid-August, Early September. The fourth time should be especially thin.

Autumn orchid type: Early June, Late June, Late July, Mid-August. The fourth time should be especially thin.

VI. Pruning

During orchid cultivation, pruning must be carried out continuously. When old leaves turn yellow and withered, they should be cut off promptly to facilitate ventilation, and some leaves whose tips have dried should also be cut off. In particular, leaves damaged by pests and diseases must be removed promptly to prevent contagion. When cutting off leaves with viral disease, the scissors used should not be used again to cut healthy leaves, to prevent virus transmission. If the same pair of scissors is used, it must be disinfected. For precious orchids, after flower buds emerge from the soil, if there are too many flower buds, keep the strong buds and remove the remaining thin, small flower buds; per pot, keeping 1-2 flower buds is suitable. If there are too many flower buds, not only will the flowers of the current year not open well, but too much of the mother plant's nutrients will also be consumed, affecting flowering the following year. Generally, orchids do not need to have their flower buds cut off. The flowers of spring orchids bloom for about half a month, after which the flowers need to be cut off; for summer orchid flowers, when the last flower on the inflorescence has been open for one week, the inflorescence should also be cut off. Precious varieties should not be allowed to be pollinated and set seed; otherwise, flowering the next year will be affected. If used for hybrid breeding, then they need extra careful cultivation so that the fruit becomes full and mature.

VII. Cold Protection

Autumn orchids should have cold protection work done early; for example, when the temperature is 2-3°C, they can be moved indoors. Cymbidium kanran, growing in the south, needs cold protection even earlier. Spring and summer orchids have relatively strong cold resistance, but if freezing occurs, they must also be moved indoors promptly. If the room temperature can be kept at 1-2°C, they can survive the winter. If a severe cold wave strikes and the room temperature drops below zero, heating must be provided promptly; generally, it is enough to keep the room from freezing. Indoors, autumn orchids should be placed on the south-facing side, and spring and summer orchids on the other side. Around noon, windows on the south and southeast sides should be opened for ventilation (for autumn orchids, on overcast days at 1-2°C, windows must not be opened, to prevent cold wind from blowing in and freezing the leaves). Autumn orchids prefer somewhat dry conditions in winter, while the potting soil of other orchids should be kept moist.

VIII. Flower Removal

For orchids growing poorly, with few leaves per clump, or with poor roots, flower removal should be carried out. For better varieties, spring orchids can appropriately have 1-2 flower buds removed; for summer orchids, when the flower buds have extended, keep 1-2 flower buds and remove the rest; in this way, the flowers can last longer, more new leaves can sprout, and old leaves are less likely to wither and die. Precious spring orchid flowers should be removed after 3-5 days of blooming, so that leaf buds grow robustly; for summer orchids, when the topmost flower has opened, they can also be cut off at a distance of several cm from the pot surface.

IX. Wind Protection

If the cultivation site is open on all sides and the terrain is relatively high, wind protection work should be done in summer when strong winds or typhoons pass through, to prevent the leaves of summer orchids or Cymbidium kanran from being broken and damaged.

X. Mist Spraying

In dry seasons, spray mist every evening on the balcony where the potted flowers are placed, mainly to make the ground moist and increase air humidity. The surface of the orchid pots should also be misted. When misting, spray upward so that the mist droplets fall finely and evenly and the leaf surfaces become moist; this can promote good orchid growth and make the leaf surfaces glossy.

XII. Pest and Disease Control

Sterilization treatment should be carried out (exposure under the scorching sun is sufficient) to prevent disease occurrence. Orchids are most prone to southern blight in rainy and high-temperature seasons, and thiophanate-methyl 800x solution or Bordeaux mixture can be sprayed for prevention. If the disease is severe, thiophanate-methyl can be used at 500-750x dilution, sprayed once every 7-10 days. Among insect pests, scale insects occur most frequently; these insects attach to the base of the leaves, and if scale insects are found, they should be removed promptly. To avoid scale insect infestation, starting in April, "1059" at 2000x solution can be used for control. In order to suppress the occurrence of orchid diseases, in addition to appropriately controlling the dryness and wetness of the potting soil at ordinary times, clay pots should also be used as much as possible and glazed pots used less when choosing flower pots. Especially for poorly growing orchids newly dug from the mountains, clay pots must be used for planting. Doing so makes the potting soil dry easily, can promote orchid growth, and reduce disease occurrence.

How should orchids be grown well?

1. Potting soil requirements: A neutral to slightly acidic soil containing large amounts of humus, loose, and well-drained is best, with a pH generally around 5.5 to 6.5. In Sichuan, Emei Xiantu and "Xinghong Brand" refined orchid growing medium are often used, and more commonly, "bamboo root soil" and leaf mold from broad-leaved forests in mountainous areas are used to cultivate orchids.

2. Placement location: Orchids can be cultivated outdoors and on balconies in spring, summer, and autumn, and a place with good ventilation, humid air, and no environmental pollution should be chosen. Being near ponds and riversides is of course good, but at least there should be tall trees or bamboo groves and shade nets to reduce sunlight exposure and lower temperature. Orchid pots are best placed on wooden stands (or steel stands); if placed on the ground, bricks should be used underneath. Household balconies can also use small galvanized iron water troughs to store water, with bricks placed on top for cultivation, increasing humidity.

3. Appropriate shading: Orchids mostly belong to semi-shade plants, and most species are afraid of direct sunlight, so appropriate shading is needed. In early to mid-April, the net can be removed and windows opened to give more sunlight to promote growth. In May, except for the midday sun, they can receive 6 hours of sunlight; starting in June, shade all day; after October, except at noon, they can be kept fully open for cultivation. Remember the proverb: "More shade makes good leaves, more sun makes good flowers."

4. Reasonable fertilizing: Orchids are naturally "vegetarian," and fertilizing should be decided according to the selected potting soil and growth condition. Those growing luxuriantly and without disease can be fertilized; those growing poorly should not be fertilized or should be fertilized only lightly. Newly potted orchids whose roots have not fully developed need 1-2 years before they can be fertilized. Generally, in June-July, when orchid leaf buds have extended to about 1.5 cm, apply a rotted liquid fertilizer once every three weeks (a thin concentration of 10% is suitable). Chemical fertilizers are taboo; in high-temperature seasons, fertilizing is not suitable. In August-September, apply diluted liquid fertilizer once every two to three weeks. Each fertilizing of orchids should be done in the evening, and in the morning water with clear water, called "return water."

5. Appropriate watering: For watering orchids, rainwater and spring water are best; tap water or rice-washing water needs to be left overnight before use. When watering, pour from the edge of the pot, and do not pour into the flower buds. The amount of water should be determined according to air temperature, the degree of dryness and wetness of the potting soil, and the growth condition of the orchid. If the leaves are large, water more; if the leaves are fine, water less. In April-May, when new buds have not yet emerged from the soil, the potting soil should be somewhat dry; if too wet, new buds easily rot; June-September is the growth period for new orchid buds, and the amount of watering should be increased; on clear days, water once each morning or evening, and never water under the scorching midday sun. In autumn, reduce the amount of water as appropriate; leaf surface misting can be used, and keeping the potting soil moist is best; in winter, the amount of water should be controlled even more, keeping it at "eight parts dry, two parts wet" as suitable.

6. Evening misting: Orchids originally grow in a humid environment, so in dry seasons, in addition to shading, misting must also be done in the evening to increase air humidity and lower temperature; water can also be poured onto the ground (table surface) where the orchid pots are placed; "one cold and one hot" can even more stimulate orchid growth.

7. Wind and rain protection: "February ghost wind" causing old leaves to yellow and fall is a normal phenomenon, and withered branches and fallen leaves can be cut off. Orchids can tolerate light rain, but must avoid plum rain, torrential rain, or continuous rain; otherwise, the heart and leaves easily rot. In rainy seasons, a small amount of plant ash can be sprinkled appropriately.

8. Pruning and flower removal: During orchid cultivation, withered, yellowed, broken leaves and diseased leaves should often be cut off to facilitate ventilation. For precious orchids, if there are too many flower buds, keep only the strong buds; per pot, 1-2 flower buds is suitable. Spring orchid flowers should be removed half a month after blooming; precious orchid flowers should be removed after 7 days, so that spring orchid leaf buds grow robustly and bloom better the following year. For summer orchids, when the last flower on the inflorescence has been open for one week, cut it off at a distance of 3 cm from the pot surface.

9. Cold protection and warmth: Because orchid varieties differ, their places of origin vary, and their cold resistance also differs, so the time to bring them indoors in winter and their indoor placement are also different. Cymbidium kanran, autumn orchids, and Cymbidium sinense grow in the south and should be brought indoors when the temperature is 5°C (or windows closed and nets drawn), and placed as much as possible in a south-facing sunny spot. Spring and summer orchids have strong cold resistance and can be brought indoors only when the temperature reaches 0°C, placed on the northeast side. Around noon on clear, windless days, windows on the south or southeast side should be opened and nets drawn for ventilation. Autumn orchids should not have windows opened on clear days at 1-2°C. Of course, if there is a greenhouse, electric lighting can be used for heating.

10. Disease and pest control: The potting soil generally needs sterilization treatment (exposure under the scorching sun is also acceptable) to prevent disease occurrence. Orchids are most prone to southern blight in rainy and high-temperature seasons; for a small amount, a wet cloth can be used to wipe it off; if there are many pots, 500-800x Bordeaux mixture or thiophanate-methyl can be used, sprayed once every 7-10 days. Among insect pests, scale insects (commonly known as "orchid lice") occur most; during the hatching period, 1% omethoate and 25% phosmet emulsifiable concentrate at 1000x solution can be used, sprayed once a week. To treat the root cause as well as the symptoms, pots should be spaced appropriately, placed at varying heights, and ventilation increased, to reduce disease occurrence.

(II) Ecological habits of orchid cultivation

Orchids originated in China. They like warmth and humidity, and especially ideal is warm winters and cool summers; high temperature and dryness must be avoided. In winter, it is best that they do not freeze, and keeping 3°C-7°C is most suitable; in summer, 25°C-28°C is suitable. In their natural distribution, orchid habitats are near streams and gullies, receiving rain and dew year-round, and the annual rainfall requirement is above 1000 mm. They require deep upper soil, rich in humus, dark brown, loose and fertile, with good water permeability and water retention, and slightly acidic soil, pH 5-PH 6.5; waterlogging is taboo.

Orchids like shade and require short sunlight duration. In natural distribution, it is shown that spring orchids require tree canopy density of 0.7-0.95; Cymbidium faberi requires 0.5-0.8, with light duration slightly longer than that of spring orchids; Cymbidium ensifolium, Cymbidium sinense, and Cymbidium kanran also require large canopy density for shading. Cymbidium plants have a dormant habit in their places of origin, which depends on the rainy season and dry season. Usually the dry season is in winter, which is the dormant period for orchids, and the rainy season is in spring and summer, which is the growth period for orchids, when they can continuously produce buds and bloom.

(III) Propagation methods for orchid cultivation Orchids are commonly propagated by division, sowing, and tissue culture.

1. Division: This can be done in both spring and autumn, generally once every three years. Any plant growing robustly with dense pseudobulbs can be divided; after division, each clump must retain at least 5 pseudobulbs connected together. Before division, watering should be reduced so that the potting soil is relatively dry. When potting after division, first cover the drainage hole at the bottom of the pot with broken tile pieces, then spread coarse gravel, occupying 1/5 to 1/4 of the pot depth, then place coarse-grained soil and a small amount of fine soil, and then plant with sandy loam rich in humus. The planting depth should be such that the pseudobulbs are just buried in the soil; leave a 2 cm rim at the edge of the pot, spread Selaginella uncinata or fine gravel on top, and finally water thoroughly, place in a shaded area for 10-15 days, keep the soil moist, gradually reduce watering, and carry out normal maintenance.

2. Seed propagation: Orchid seeds are extremely fine, and the seed contains only one incompletely developed embryo, with very low germination ability. In addition, the seed coat does not easily absorb water, so sowing by conventional methods cannot germinate; therefore, orchid mycorrhizal fungi or artificial culture medium are needed to supply nutrients for germination. For sowing, it is best to select fruit that has not yet split; after sterilizing the surface with 75% alcohol, take out the seeds, soak them in 10% sodium hypochlorite for 5-10 minutes, take them out and rinse them 3 times with sterile water, then sow them in culture bottles containing medium, then place them in a dark culture room, keep the temperature at about 25°C, and after germination move them into the light, where they can form protocorms. From sowing to transplanting takes half a year to one year. Tissue culture has already been successful, and where conditions permit, this method can be used for propagation.

(IV) Orchid cultivation techniques

1. Site selection: The site should be open on all sides, well ventilated, close to water surfaces, with humid air and no coal smoke pollution. On the southwest side of the site, evergreen broad-leaved trees can be planted, with canopy density of about 0.7, which can reduce afternoon sunlight exposure and regulate humidity and temperature.

2. Watering: Rainwater or spring water is suitable; water containing salt and alkali should not be used. If tap water is used, it should be left standing for several days before use. Watering should depend on temperature conditions: in spring, the amount of watering should be less; in summer, more; the plum rain season coincides with orchids sprouting leaf buds, so the potting soil should be somewhat dry; after autumn when the weather turns cooler, the amount of watering should be reduced as appropriate, keeping it moist is enough. In winter indoors, it should be dry, with fewer waterings, and watering should be done at noon. Orchids can tolerate light rain, but continuous rain or torrential rain easily causes heart and leaf rot, so attention must be paid to rain protection.

3. Fertilizing: For planting orchids, cake fertilizer is suitable. Mix 4 parts plant ash, 10 parts bean cake, and 10 parts bone meal evenly, place in a vat, add water several times until the bean cake is soaked and swollen, then cover and seal, and after one year of decomposition, make it into dry granules. When using, place it on the pot surface. If whole manure is used, it should also be decomposed for one year, diluted with water, filtered, and then used. Generally, fertilizing starts in May and stops at the Start of Autumn, with the principle of thin fertilizer applied frequently. Fertilizing should be done in the evening, and the next morning water once with clear water.

4. Shading and cold protection: Except in early spring and winter, they should be placed under open-air sheds. The shade shed requires good ventilation. When orchids are first brought out in March-April, they can receive more sunlight, and afterward the shading time gradually increases. In winter, orchids must be moved indoors for cold protection, and room temperature kept at 1°C-2°C is sufficient. In addition, after orchids are brought out in spring and before they are brought indoors in autumn, attention must also be paid to frost protection.

5. Pest and disease control: The main pests and diseases of orchids are:

(1) Southern blight: Mostly occurs in the plum rain season. Attention should be paid to ventilation and light transmission, and good drainage of the potting soil for prevention. After onset, remove the infected potting soil and sprinkle pentachloronitrobenzene powder or lime.

(2) Anthracnose: Occurs year-round, and is even more rampant in high-temperature and rainy seasons. In addition to improving environmental conditions, during the onset period, 50% methyl thiophanate wettable powder at 800-1500x solution can first be sprayed for treatment, once every 7-10 days, and then supplemented with 1% equal-amount Bordeaux mixture, once every half month.

(3) Scale insects: They reproduce fastest under high temperature, high humidity, and poor air circulation. Use conventional methods for control.

In summary, to grow orchids well, one must master their natural growth environment conditions, adopt reasonable measures, and strengthen maintenance and management. According to "Orchid Cultivation Formula": "Do not bring them out in spring, do not expose them to sun in summer, do not let them dry in autumn, do not keep them wet in winter." This is a summary of China's orchid-growing experience.

A brief discussion of rational pesticide use for orchids

Fungicides are agents for preventing and controlling crop diseases. In ordinary times, when preventing and controlling orchid diseases, we must choose according to the different properties and modes of action of different categories of fungicides. One category is protective fungicides, whose role is to treat plants or the environment in which plants are located before pathogens invade. They need to be used before plants come into contact with pathogens or before disease occurs to achieve results, such as Bordeaux mixture, lime sulfur mixture, mancozeb, zineb, and so on. There is also another category, therapeutic fungicides. We often come into contact with this kind of fungicide; its characteristic is systemic activity. The use of this kind of fungicide is when the pathogen has already invaded the plant body or the plant is already infected, and at this time it is applied to reduce or eliminate plant disease. Applying the pesticide in the early stage of plant disease gives better results.

The early and peak stages of disease for different pathogens also differ, and are greatly influenced by the external environment, especially by the growth and development status of the infected crop and by temperature and humidity (therefore, we must grow strong orchid plants). When preventing and controlling diseases, it is better if everyone can be familiar with the living habits and epidemic patterns of the pathogenic pathogens, and can carry out disease control according to different seasons and temperature environments; this plays a huge role in the effective exertion of pesticide efficacy. Crop diseases caused by various pathogens are different, and disease symptoms are also obviously different. Therefore, when choosing fungicides, the pesticide must be suited to the disease. Moreover, the efficacy should be significant and lasting; one should not blindly pursue high efficiency, broad spectrum, or even "all-purpose" pesticides, as if no matter what the disease, I treat it with only one pesticide. This is definitely not acceptable. When using pesticides, attention should be paid to preventing the development of pathogen resistance, that is, the same fungicide cannot be used continuously, nor can the same category of fungicide be used continuously several times in one growth period. In particular, the number of uses of systemic agents should be limited; for example, in production, systemic agents can be used in combination or rotation with chlorothalonil, mancozeb, and so on.

In our daily pesticide use, we should adopt corresponding control measures according to the patterns of pathogen infection. When using fungicides to spray directly on orchid plants, attention should be paid to the influence of natural conditions, to prevent loss of efficacy or pesticide damage. When temperature and humidity are relatively high, the concentration of the pesticide used can be appropriately reduced; for pesticides that easily decompose or volatilize under strong light, application should be done on overcast days or in the evening. Different pesticides all have certain ranges of use. Only by deeply understanding them and mastering their usage characteristics can pesticides be selected correctly and achieve twice the result with half the effort. Carbendazim is a systemic fungicide commonly used by everyone, and can prevent and control dozens of fungal diseases. Ascomycetes and deuteromycetes are especially sensitive to this pesticide, but it is ineffective against bacteria and diseases caused by oomycetes among fungi. Therefore, when it is confirmed that a plant is infected with a fungal disease and repeated use of carbendazim is ineffective, consideration should be given to switching to phenylamide pesticides (such as metalaxyl). This type of pesticide is mainly used for downy mildew, phytophthora disease, and pythium disease caused by oomycetes, while its effect on diseases caused by other fungi and bacteria is very poor. Chlorothalonil is a non-systemic broad-spectrum fungicide with preventive effects on many plant fungal diseases. It can prevent pathogen spores from germinating, hinder mycelial development and spore formation, and can also control diseases that have developed resistance to carbendazim, but its control effect on diseases caused by soilborne Pythium is poor. Therefore, frequently change fungicides (Huakang is said to be able to kill all diseases; I do not know whether this is true or false. When I use it, I do not dare to be careless and still mix it with other fungicides), striving for the greatest possible protection of orchid plants and sparing them from the torment of disease. When orchids grow healthily, orchid friends are happy too.

Figure 1 Ring spot disease + anthracnose (Colletotrichum)

Ring spot disease + anthracnose (Colletotrichum) ordinary preventive pesticide use:

Pesticide name: 77% Kocide wettable powder; mode of action: broad-spectrum protective fungicide; method of use: 1000x solution / 3-4 times / interval 7 days, spray / underside of leaves, upper surface of leaves; can also prevent: brown spot disease, anthracnose, leaf spot disease, ring spot disease, bacterial brown spot disease;

Pesticide name: 25% Sportak emulsifiable concentrate; mode of action: broad-spectrum fungicide; method of use: 1500x / 2-3 times / interval 8 days, spray / underside of leaves, upper surface of leaves; can also prevent: anthracnose, leaf spot disease, sooty mold, black spot disease, round spot disease, ring spot disease;

Pesticide name: 80% mancozeb wettable powder; mode of action: broad-spectrum protective fungicide; method of use: 800x / 3-4 times / interval 6 days, spray / underside of leaves, upper surface of leaves; can also prevent: anthracnose, leaf spot disease, sooty mold, black spot disease, round spot disease, ring spot disease;

Ring spot disease + anthracnose (Colletotrichum) supplementary notes:

1. Because most of the control prescriptions for anthracnose are emulsifiable concentrates or mancozeb types, pesticide use must pay attention to weather temperature and ultraviolet index.

2. When the temperature exceeds 30 degrees, avoid emulsifiable concentrates and copper-based pesticides as much as possible; when the weather ultraviolet index is too high, choose as much as possible to apply pesticides before 5 a.m. or after 6 p.m.

3. It is recommended that during normal pesticide use, two prescription fungicides can be selected for mixed use, so that multi-faceted treatment and defense can be achieved.

Picture 2 Ring spot disease + leaf spot disease

Ring spot disease + leaf spot disease ordinary preventive pesticide use

Pesticide name: 80% mancozeb wettable powder; mode of action: broad-spectrum protective fungicide; method of use: 800x / 3-4 times / interval 6 days, spray / underside of leaves, upper surface of leaves; can also prevent: anthracnose, leaf spot disease, sooty mold, black spot disease, round spot disease, ring spot disease;

Pesticide name: 77% Kocide wettable powder; mode of action: broad-spectrum protective fungicide; method of use: 1000x solution / 3-4 times / interval 7 days, spray / underside of leaves, upper surface of leaves; can also prevent: brown spot disease, anthracnose, leaf spot disease, ring spot disease, bacterial

Ring spot disease + leaf spot disease supplementary notes: Before the leaves of diseased orchids dry up and wither, if not carefully observed, ring spot disease is often mistaken for ordinary leaf spot disease or leaf blight. Treatment is often controlled as leaf spot disease, which is also a disease relatively easy to control.

2. It is recommended that during normal pesticide use, two prescription fungicides can be selected for mixed use, so that multi-faceted treatment and defense can be achieved.

Picture 3 Mild nutrient deficiency disease (zinc, magnesium, iron)

Mild nutrient deficiency disease (zinc, magnesium, iron) ordinary preventive pesticide use: Although this is a diseased state, it is not contagious. At ordinary times, fertilize to supplement some trace elements and fertilizers containing zinc, magnesium, iron, and calcium. Mild nutrient deficiency disease (zinc, magnesium, iron) supplementary notes: At ordinary times, fertilize to supplement some trace elements and fertilizers containing zinc, magnesium, iron, and calcium.

Picture 4 Soft rot + black spot disease

Pesticide name: 72% agricultural streptomycin sulfate wettable powder; mode of action: antibiotic fungicide; method of use: 800x / 2-3 times / interval 7 days, spray, root drench; can also prevent: bacterial brown spot disease, soft rot;

Soft rot + black spot disease supplementary notes: Because this is a disease condition occurring simultaneously from fungi and fine particles, two different fungicides must be mixed for use. Because the mixing of two fungicides each has its own pesticide concentration multiple, this often brings confusion to beginner orchid friends. Here is a renewed supplementary explanation: ratio: need 100 jin of water, use the bacterial one, streptomycin sulfate 500x mixed with the fungal one, carbendazim, 1000x.

1. 100 jin of water at streptomycin sulfate 500x equals streptomycin sulfate needing to be added in an amount of 100 grams.

2. 100 jin of water at carbendazim 1000x equals carbendazim needing to be added in an amount of 50 grams.

3. That is, using 100 grams of streptomycin sulfate equals "500x" + 50 grams of carbendazim equals "1000x", simultaneously put into 100 jin of water and mixed for use; only then is it considered correct pesticide amount preparation.

Picture 5 Leaf tip anthracnose + leaf blight

Leaf tip anthracnose + leaf blight ordinary preventive pesticide use

Pesticide name: 25% propiconazole emulsifiable concentrate; mode of action: broad-spectrum systemic fungicide; method of use: 1500x / 2-3 times / interval 8 days, spray / underside of leaves, upper surface of leaves; can also prevent: brown spot disease, round spot disease, anthracnose, leaf spot disease, leaf tip blight;

Pesticide name: 10% Score water-dispersible granules; mode of action: broad-spectrum systemic fungicide; method of use: 3000x / 2-3 times / interval 8 days, spray / underside of leaves, upper surface of leaves; can also prevent: brown spot disease, leaf spot disease, black spot disease, round spot disease, leaf blight, ring spot disease, leaf tip blight, sooty mold;

Leaf tip anthracnose + leaf blight supplementary notes: Because this is a cross symbiotic occurrence of two pathogens, it is recommended to use two fungicides for relatively simple control. The method of mixing the two fungicides is repeated here once. When two disease conditions occur simultaneously, two different fungicides must be mixed for use. Because the mixing of two fungicides each has its own pesticide concentration multiple, this often brings confusion to beginner orchid friends. Here is a new supplementary explanation: ratio: need 100 jin of water, use the bacterial one streptomycin sulfate 500x mixed with the fungal one carbendazim 1000x.

1. 100 jin of water at streptomycin sulfate 500x equals streptomycin sulfate needing to be added in an amount of 100 grams.

2. 100 jin of water at carbendazim 1000x equals carbendazim needing to be added in an amount of 50 grams.

3. That is, using 100 grams of streptomycin sulfate equals "500x" + 50 grams of carbendazim equals "1000x", simultaneously put into 100 jin of water and mixed for use; only then is it considered correct pesticide amount preparation.

Picture 6 Leaf margin black spot disease

Leaf margin black spot disease ordinary preventive pesticide use

Pesticide name: 80% mancozeb wettable powder; mode of action: broad-spectrum protective fungicide; method of use: 800x / 3-4 times / interval 6 days, spray / underside of leaves, upper surface of leaves; can also prevent: anthracnose, leaf spot disease, sooty mold, black spot disease, round spot disease, ring spot disease.

Pesticide name: 10% Score water-dispersible granules; mode of action: broad-spectrum systemic fungicide; method of use: 3000x / 2-3 times / interval 8 days, spray / underside of leaves, upper surface of leaves; can also prevent: brown spot disease, leaf spot disease, black spot disease, round spot disease, leaf blight, ring spot disease, leaf tip blight, sooty mold;

Pesticide name: 25% Sportak emulsifiable concentrate; mode of action: broad-spectrum fungicide; method of use: 1500x / 2-3 times / interval 8 days, spray / underside of leaves, upper surface of leaves; can also prevent: anthracnose, leaf spot disease, sooty mold, black spot disease, round spot disease, ring spot disease;

Pesticide name: 50% Shibagong wettable powder; mode of action: broad-spectrum fungicide; method of use: 2000x / 2-3 times / interval 8 days, spray / underside of leaves, upper surface of leaves; can also prevent: anthracnose, leaf spot disease, sooty mold, black spot disease, round spot disease, ring spot disease;

Supplementary note on leaf-edge black spot disease: In fact, many of the fungicides used for orchid leaf diseases have similar properties, but as our professional introduction, we have no choice but to present all the disease conditions to orchid enthusiasts for their understanding. In general, the best choice of fungicides is broad-spectrum and systemic pesticides of both types.

Experience-based reminder: In my experience, the key work in purchasing pesticides is choosing manufacturers with good reputation and checking the labeled ingredients, to avoid the psychological comfort of thinking you have a fungicide when it turns out to be fake ingredients, causing the disease to go uncontrolled and missing the golden time for treatment.

Experience-based reminder: The second cause of harm is: thinking these pesticides may not have sufficient active ingredients, so you increase the concentration or reduce the dilution ratio, only to find out this time you bought genuine pesticide, and as a result the increased concentration caused severe pesticide damage. Haha! All you can do is silently ask heaven.

Image 7: Blight disease

Preventive fungicide use for blight disease in normal times

Pesticide name: 72% Kelu wettable powder; Mode of action: systemic fungicide; Usage: 1500x dilution / 2-3 times / 10-day interval, drench root and stem; Also prevents: blight disease

Pesticide name: 50% Anke wettable powder; Mode of action: systemic fungicide; Usage: 12500x dilution / 2-3 times / 10-day interval, drench root and stem; Also prevents: blight disease

Supplementary note on treating blight disease after infection:

1. During peak disease periods, continuous preventive fungicide application is essential. Having understood the characteristics of stem rot, we can only use targeted fungicides.

2. 72% agricultural streptomycin sulfate soluble powder at 800x dilution, 77% Keshade powder at 1000x dilution, spray on leaf undersides, leaf surfaces, and crown.

3. Mifen'an (emulsifiable concentrate) at 1500x + tetracycline (powder) at 2000x + dimethomorph (powder) at 2000x dilution, spray on leaf undersides, leaf surfaces, and crown.

4. Antaisheng at 500x + Mifen'an at 1500x + streptomycin sulfate at 500x dilution, spray on leaf undersides, leaf surfaces, and crown. (When applying fertilizer or pesticide, you must spray the leaf undersides, because plants absorb through the stomata on the leaf undersides.)

5. Every 20 days or so, use Dexon at 800x + tetracycline at 3000x dilution to thoroughly drench the roots.

6. Fungicides must be rotated and alternated to prevent resistance from developing and delaying treatment.

Basic Principles of Orchid Cultivation and Management Techniques - Orchid Cultivation Techniques

1. Preparation of growing medium. Planting orchids requires a specially prepared growing medium, also called orchid soil. The growing medium for orchids should be loose and breathable, well-draining, with adequate nutrients, and free from hidden pests and diseases. The composition of the growing medium is made from one or several basic components (substrates). These basic components include soil, fertilizer, and other materials, with many types available. Some components may seem unrelated to soil, but they are all substrates on which orchids depend for stabilizing the plant and for growth and development.

(1) Growing medium formulas.

In East China, orchid growers generally prefer orchid soil from Shaoxing, Yuyao, and other places. In recent years, Emei He Wang Pai Xiantu has also become popular, but these growing media are limited in quantity and expensive, and can only be used for repotting. Large-scale ground planting requires hundreds or thousands of tons of growing medium, so only local materials can be used. After years of practice and repeated screening, we determined the best formula: 4 parts yellow sandy soil, 4 parts sawdust, 2 parts river sand; or for yellow loam soil, 1 part river sand, 1 part sawdust, 1 part yellow loam soil. All are thoroughly mixed. The pH of the prepared growing medium should be between 6.5-6.8, loose and breathable, with excellent water retention and drainage, and comprehensive nutrition. River sand and sawdust serve for water drainage and aeration; sawdust is decomposed by bacteria and can slowly release nitrogen, phosphorus, potassium, etc. Yellow loam soil also contains various trace elements. After years of observation, this formula is very suitable for orchid growth. It is especially suitable as a substrate for domesticating and cultivating wild orchids. It is suitable for Cymbidium goeringii (spring orchid) and Cymbidium faberi (Huilan), and also ideal for Cymbidium ensifolium (Jianlan) and Cymbidium kanran (Hanlan). Regardless of flowering rate or stress resistance, there are significant increases.

(2) Bamboo root soil.

This refers to the soil at the base of bamboo clumps that have been growing for many years. Due to the spreading of bamboo rhizomes and roots, as well as the decomposition of bamboo leaves and sheath husks, this soil becomes loose in structure, well-draining, and has a certain fertility without being excessively fertile, making it suitable for orchid growth. The quality of bamboo root soil depends on three factors: first, the original soil quality, which is the predecessor and foundation of the bamboo root soil, with sandy loam being the best; second, the age of the bamboo clump planting, the longer the time, the more thorough the effect of bamboo roots, leaves, and rhizomes; third, the distance from the bamboo stump, the closer to the bamboo stump, the better the soil.

(3) Vetch chaff soil.

Vetch chaff is made by harvesting, sun-drying, and crushing the plants of green manure (Chinese milk vetch). Mix vetch chaff with bamboo root soil or ordinary sandy loam, pile up, and compost to make vetch chaff soil. The preparation method is: choose a rain-sheltered site, spread a layer of soil, then a layer of vetch chaff, pour a round of *manure water, and pile up layer by layer; after piling, sprinkle water on the surface to moisten, then cover with thin mud to seal. After piling and fermenting for half a year, it is ready for use.

When using, mix in proportion with other growing media.

(4) Leaf mold.

Use fallen leaves or green grass and tall stalks, pile up, water or apply fertilizer, cover with thin mud to seal, and after composting and screening, it is ready. It is best to use green grass that has not set seeds, and after full composting, kill pests, diseases, and weed seeds, otherwise there will be many weeds in the orchid pot later.

(5) Mountain soil.

This is the forest soil where wild orchids originally grow. It is formed by years of accumulation and decomposition of dead branches and fallen leaves mixed with soil. Naturally formed leaf mold contains rich humus, is loose and breathable, and is very suitable for orchid growth. When transportation is convenient, digging large amounts of mountain soil for planting orchids is relatively simple and economical, and even better for domesticating wild orchids. The humus soil under broadleaf forests, especially the leaf mold under chestnut trees, is an ideal soil for orchids.

(6) Pond mud.

When repairing ponds and fish ponds in winter, dig out the mud, sun-dry it, then break it into fine particles. It can be used to cultivate all flowers, including orchids.

(7) Field soil.

Select loose topsoil from fields, mix in a little sandy soil or a small amount of rice hull ash, then add some composted manure or fermented organic fertilizers such as soybean cake and rapeseed cake, to improve soil structure and enhance fertilizer efficiency. After turning and mixing evenly several times, then screen. This soil is nearly neutral, not as good as humus soil. So it is only used reluctantly when there is no suitable humus soil or mountain forest sandy loam, and is mostly used for cultivating coarse orchid varieties.

(8) Cow dung soil.

Crush and grind fermented dry cow dung into fine powder, mix into sandy soil or field topsoil at a 1:3 ratio. It is best to select cow dung from cattle fed dry feed in winter, because after rumination through the cow's stomach, although the fiber is finely broken, it still retains some elasticity, and being plant fiber, it contains certain nutrients. This cow dung soil is soft and fertile, extremely suitable for the aerial roots of orchids. In Taiwan, China, orchid growers often use this cow dung soil as a filling material for cultivating terrestrial orchids, with good results. Abroad, for cultivating terrestrial orchids, generally 5 parts leaf mold or humus soil plus 1 part sand; or 3 parts peat soil plus 1 part river sand, mixed with crushed dry cow dung, thoroughly mixed before use. For epiphytic orchids, the growing substrate is mainly moss and ferns, with a small amount of tree leaves, small pieces of charcoal, and crushed dry cow dung added. Before using soil to plant orchids, expose the soil to sunlight for disinfection and sterilization. In summer, spread the soil out and let the sun expose it for more than 3 days, which can kill pathogens and insect eggs. Before use, the growing medium should be tested and its pH adjusted. For overly acidic soil, lime can be used to adjust. For overly alkaline soil, use superphosphate, ferrous sulfate, etc., mixed into the soil. In short, it is best to control soil pH to slightly acidic neutrality (i.e., pH 5.5-7). Using organic fertilizers, such as composting green grass and tree leaves, and adding them to the soil to change the soil pH is a better approach. In addition, before planting orchids, the nutrient soil should be screened and graded, separating large particles from small ones.

When planting orchids, place large particles at the bottom of the pot to facilitate drainage. At the same time, the moisture level of the soil should be properly adjusted, neither too wet nor too dry. Preferably, squeeze the soil in your hand with force, and the soil can form a ball; release your hand and shake it, and the soil breaks apart into granules again. This moisture level is appropriate.

2. Preparation of the orchid growing site. 1. Productive ground planting. The original environment for terrestrial orchids is growing in mountain forests and secluded valleys, with high and spacious terrain, shaded by trees, forming a moist microclimate. Small temperature differences, clean air.

When introducing and domesticating, one should first simulate their wild environment to achieve lush flowers and leaves. Currently, with industrial development and urban modernization, greening work cannot keep up correspondingly for the time being, and is affected by pollution from factories and vehicles. Therefore, orchids cultivated in cities are not as robust as those grown in suburbs. There is a gap with the original environment of wild orchids, and a great difference from the meteorological factors of the original habitats of Cymbidium kanran and Cymbidium ensifolium. Therefore, careful design and practical arrangements for environmental factor regulation were made for the domestication and planting site.

The orchid nursery covers about 1.5 hectares (approximately 15,000 sq m), rectangular in shape, with a rectangular pond for storing rainwater. Within the nursery, every 2.5 m or so, a 2.5 m tall moso bamboo pole is fixed, with bamboo poles horizontally tied on top to form a frame, used to lay the first layer of shade netting. At 20 cm below the first layer of shade netting, another horizontal thin bamboo pole is placed to lay the second layer of movable shade netting. The first layer of shade netting is basically fixed from spring to autumn, and the second layer can be retracted or extended as needed. Carefully regulate light and temperature. The seedling bed width is 1.2 m, length 12-16 m (depending on terrain), height about 30-40 cm (5-7 bricks high), with 50 cm between seedling beds, and pathways 130 cm wide. This facilitates daily management. In winter, every two beds are covered with a plastic greenhouse for warmth. On snowy days, pay attention to clearing snow to avoid excessive snow crushing the plastic greenhouse. Approximately every mu (1 mu ≈ 667 sq m) of land, two water tanks with a storage capacity of 1 cubic meter are built to treat tap water. In winter, 100-150 watt light bulbs are placed about every 4 m inside the plastic greenhouse, mainly for heating.

2. Open-field cultivation

(1) Ground planting of orchids under tree shade.

This is for ornamental purposes, using sparse tree shade in front of houses, wall corners, or scenic areas to plant appropriately in the ground, but the original poor clay soil must be dug out and replaced with loose humus soil or good field topsoil.

When winter arrives, spread some rice straw on the soil surface around the roots to prevent frost damage to orchid roots. If there is severe cold, also lay straw curtains or other soft coverings over the leaf clusters to prevent frost damage. This type of ground-planted orchid cultivation generally can be extensive and left to grow naturally, except during the hottest summer when management and protection need to be strengthened. Orchids planted in the open field are all coarse varieties without petal-type classification. In the following spring, after the weather warms up, the cold-protection coverings can be removed. After years of growth, as long as timely watering and fertilizing are done, its adaptability is still relatively strong, and it can bloom abundantly year after year, with delicate fragrance drifting far, making it a fine item for embellishing the countryside.

However, when arranging ground-planted orchids, besides considering the tranquility of the layout

(2) Pot cultivation of orchids.

This refers to cultivating orchids under a shade shed.

For pot cultivation of orchids, it is best to use clay pots, i.e., unglazed earthenware pots, which have good breathability, can drain water, and are inexpensive. They are economical and practical for orchid cultivation. But clay pots are relatively rough and not attractive, unsuitable for exhibition. Porcelain pots or glazed pots are attractive in appearance, but have very poor breathability and drainage. If used for long-term orchid cultivation, they can easily rot orchid roots, making it difficult for orchids to grow vigorously. So when using porcelain or glazed pots for orchids, more drainage tiles or shell fragments must be placed at the bottom of the pot; and watering should be controlled, not excessive. If using clay pots to grow orchids, they can be placed inside larger porcelain or glazed pots for exhibitions. Yixing purple clay pots are attractive and elegant in appearance, and have a certain breathability, making them quite suitable for orchid cultivation. Newly purchased orchid pots must be soaked in water for several days, especially newly fired clay pots, which must absorb enough water to completely eliminate their fiery dryness. For general orchid cultivation, newly planted orchids mostly use new pots, and repotting mostly uses old pots. For potted orchids, it is best not to place them directly on the ground, because they are susceptible to pest damage and weed overgrowth. Especially in hot summer, when the blazing sun heats up and ground temperature rises, harming orchid plants; during thunderstorms and plum rain season, the humid heat rises even more, easily steaming orchid roots; and because they are close to the ground, ventilation is poor. This is unfavorable for aerial root growth. To reduce these effects, place orchid pots on orchid benches made of cement boards, facilitating vertical air convection, continuously supplying fresh air, promoting orchid respiration, enhancing metabolic function, accumulating nutrients and energy production, making orchids grow robustly, and also avoiding ants, slugs, and other pests damaging orchid roots. If conditions are limited, use an empty clay pot turned upside down on the ground, and place the potted orchid on top.

3. Orchid room cultivation. The orchid room is mainly for overwintering terrestrial orchids.

Different orchid species have different ecological habits, so the time for moving indoors for winter and the room temperature requirements also differ. Terrestrial orchids can generally be cultivated outdoors as long as the temperature is not below 7°C-8°C. In Jiangsu and Zhejiang areas, it is customary after the Start of Winter to move Cymbidium ensifolium, Cymbidium kanran, and Cymbidium sinense (Baosui orchid), which require slightly higher temperatures, indoors for cultivation, and move some Cymbidium goeringii and Cymbidium faberi with flower buds to corridors or cold-protected areas to avoid early frost damage affecting flower bud development. After Minor Snow, gradually move potted orchids grown from pseudobulbs and weak small plants, especially those with pure-color petals, indoors, placing them on orchid shelves near windows to receive sunlight. After Major Snow, move all potted orchids indoors for maintenance. Before orchids enter the orchid room, first wash the area around the orchid pots clean, which can prevent mud from contaminating insect eggs and mold, and also looks clean and elegant. When placing orchid pots, pay attention to reasonable arrangement, facilitating both sunlight penetration and ventilation. When terrestrial orchids overwinter indoors, the key is to manage temperature and humidity well. Generally, room temperature should be maintained above 7°C-8°C, and for Cymbidium sinense, ideally 10°C-15°C. After orchid pots are moved indoors, if the weather is not yet severely cold and freezing, open the south-facing windows around noon, and open small ventilation windows on the north side, to facilitate indoor air circulation. In the evening, if the indoor temperature is still above 5°C, the small ventilation windows on both south and north sides can be slightly opened; if below 5°C, all windows should be closed. In deep winter, only on windless sunny days at noon, slightly half-open windows for a little ventilation, and close doors and windows when the sun shifts; in the evening, hang straw curtains or cotton cloth curtains. If the temperature continuously drops below 3°C-5°C, a coal stove with a chimney pipe can be used for heating. After the Start of Spring, the climate gradually warms up, and on clear noons, all doors and windows of the orchid room can be opened, but pay attention to temperature changes; in the afternoon when temperature gradually drops, the south windows should be half-opened; before nightfall, close everything again.

During this period, the orchid room temperature should preferably be maintained around 10°C. If the temperature is too high, it will cause early-flowering varieties of Cymbidium goeringii to bloom prematurely, and the flowers will also wilt easily. In early spring, be especially careful to prevent late spring cold, which affects flower bud growth and can even freeze orchid roots.

After Awakening of Insects, all Cymbidium goeringii and Cymbidium faberi without flower buds can be moved out, placed on open-air benches, and at night, reed curtains should be added on the shed frame to prevent frost damage. All orchids with flower buds should still remain in the orchid room for maintenance, and can only be moved outdoors after Qingming; but at night, still pay attention to preventing late frost. During indoor orchid cultivation, especially in severe cold seasons, special attention must be paid to the moisture level of potted orchids. Pot soil should be dry. When to water can be determined by looking at the pot surface: if the surface soil is in a powdery loose state, while the soil below is still slightly moist, do not wait until the pot soil is completely dry before watering. When watering, first move the orchid pot down and place it on the ground, water along the pot rim groove, and never let water soak into the leaf cluster. Alternatively, place the orchid pot in a water tank for a few minutes of shallow soaking, with water limited to reaching the middle of the pot. When watering, if water soaks into the leaf sheaths, promptly wipe off the water marks with a dry cloth, or let sunlight dry it before moving back indoors. Since orchids are placed indoors for long periods, many dust particles often accumulate on the leaf surfaces, hindering metabolism. Choose clear warm weather, around noon, move the pots outdoors in the sunlight, use a fine-nozzle sprayer to spray and clean the leaf surfaces, washing away dust, and after the water dries, move back indoors. If the water marks are not dry, the wet parts of orchid leaves are prone to turning black and wilting. For indoor orchid cultivation during heating periods, indoor temperatures are often too high, the leaf clusters appear dry, the pot soil surface is dry and loose, or the moss on the pot surface looks withered. Then promptly spray some water on the pathways and walls, letting it evaporate, to regulate temperature. In short, for indoor orchid cultivation, both the orchid plants in the pot and the moss on the pot surface should maintain green vitality. For hobbyist orchid growers, due to limited conditions, they can use an outdoor south-facing sunny spot along a wall, leaning against the wall on one side, and building a single-slope ground box with bricks on the other three sides. The size can be determined by the number of pots. On the sloped surface of the ground box, install wooden-framed glass windows or plastic film windows that can be opened and closed. For orchids with long and tall leaves, place them in higher positions near the wall, on inverted empty flower pots, or on stacked bricks, wooden strips, or cement boards at appropriate heights. Short orchid pots are arranged in rows forward, and all leaf tips or the tops of curled leaves must not touch the glass or plastic film of the window. In severe cold seasons, whenever the temperature is too low or on snowy and windy days, the sloped windows must be covered with sufficient straw curtains or other coverings to prevent cold air from entering. On clear and mild days, especially after the Start of Spring, when sunlight shines, the cold-protection straw curtains can be removed; at noon when sunlight is strong and temperature is slightly higher, the window cover can be lifted to create a gap for fresh air. After the sun shifts, immediately close the window cover. Daily attention should be paid to not letting excessive water droplets condense on the window glass, to prevent them from dripping into the leaf clusters, as wet parts often turn black and rot, or even die.

3. Planting Orchids. 1. Planting timing. Whether repotting or new planting, the choice of timing has a great impact on the survival, growth, and development of orchids. Therefore, it is very important. Generally, the more suitable time is during the orchid's dormancy period, i.e., March-April, before new shoots emerge; by seasonal terms, it is between the Spring Equinox and Qingming. If after new shoots have emerged, operation is very inconvenient, and a little carelessness can break or damage new shoots. When the orchid's dormancy period is about to end, and new shoots and new roots are about to grow but have not yet grown, planting at this time is best. Shortly after planting, they can grow roots and shoots and resume normal growth. If planted too early, orchids are not easy to recover after planting, and if encountering low temperatures, cold waves, late frost, or spring thunder, frost damage is often caused. In the Yangtze River basin, orchid rooms are rarely heated in winter. Winters are very cold, so dividing in severe winter is not advocated. To facilitate operation during division, the soil can be appropriately dried before division, making roots turn white and produce inconspicuous shrinking, making the originally brittle and easily broken fleshy roots soft, so that during division and potting, not too many roots are broken. For larger orchid nurseries, the planting workload is large, and the time spent is long. Precious varieties should be arranged for planting at the best time. Ordinary varieties can be postponed or advanced as appropriate.

2. Using orchid seedlings for propagation. Orchid seedlings used for propagation should be selected from well-grown, pest-free and disease-free plants.

After 2-3 years of cultivation, orchids need soil replacement or repotting, and at this time, division propagation should be combined. When repotting, support the bottom of the pot with the left palm, extend the right fingers carefully into the orchid leaf cluster to block the pot soil, then lay the orchid pot on its side, tilting the pot sideways facing the person, with the lower edge of the pot mouth touching the ground. At this time, lift the pot slightly with both hands, gently tap the lower edge of the pot against the ground, loosening the pot soil, rotate the pot, change the contact point of the pot's lower edge against the ground, so that the pot soil gradually loosens evenly and separates from the pot. Support the orchid plant with the right hand, remove the pot with the left hand. If the orchid plant is too tall, tap the lower edge of the pot against the edge of a wooden chair or cement platform, letting the orchid leaves hang in the air without being injured or broken. After the orchid pot soil separates from the pot, lay the orchid seedling and pot soil flat, so that the soil ball does not suddenly loosen and crack, causing orchid root breakage. Then carefully pat the soil ball loose, gradually shake off the old pot soil. Carefully grasp the pseudobulbs, to avoid damaging leaves and tender shoots, especially protecting root tips. Cut off already yellowed and withered leaves, decayed bracts on pseudobulbs, and rotted, dried, hollow old roots. But for pseudobulbs with new shoots, the leaves should be retained as much as possible to promote good growth of new shoots. For the larger clumps that have been selected and cleaned, find the natural gap where two pseudobulbs are relatively far apart and easily loosened when shaken by hand, cut apart the two pseudobulbs, which predecessors called "opening the road," then hold the bases of the two clumps with both hands, gently shake and slowly pull along the road to divide into two clumps. Properly prune the divided orchid clumps, then soak in 800x water-diluted Topsin solution for 10-15 minutes, only soaking roots, not leaves; alternatively, disinfect with 1000x potassium permanganate solution. Note to only disinfect the wounded parts, then air-dry the orchids in a cool, ventilated place. When orchid roots become soft and easy to bend, they can be planted. Generally, on clear days, air-drying for half a day is sufficient, but of course, not too dry.

3. Planting procedure. For divided orchid clumps, do not divide too sparsely; each clump should have at least 3-5 seedlings, preferably keeping one-year-old, two-year-old, and three-year-old plants in the same clump.

(1) Pot padding.

Cover the drainage hole at the bottom of the pot with a piece of tile, then gradually fill with bricks, tiles, or shells, filling large gaps with mud particles or pea gravel, generally about 1/2-1/3 of the pot's internal height. The remaining clear height is about 10-15 cm, reserved for the growing medium layer. The specific height should be determined according to the orchid species, the length of orchid roots, and the height of the pot. The padding should not be filled too densely or too solidly; some gaps should be retained. Practice has proven that some new roots can grow well in the gaps of the padding layer.

(2) Planting.

On the padding layer, first fill 2-3 cm of growing medium, press lightly with the hand, then place the orchid upright on it. Depending on the plant and pot size, you can plant several individual plants, 2 clumps, 3 clumps, or more clumps in one pot. 3 clumps should be planted in a tripod arrangement. 4 clumps can be planted in a square. 5 clumps should be arranged in a plum blossom pattern. Orchid roots should spread naturally, and leaves should spread in all directions. Slowly place the orchid roots into the pot, letting them spread naturally, trying not to rub against the inner wall of the pot. After the orchid plant is in the pot, gradually fix the plant's posture. For one clump per pot, the old pseudobulbs should be positioned to one side, leaving room for new shoots to develop. For multiple clumps per pot, the old pseudobulbs of each clump should be relatively gathered toward the center of the pot, so that new roots and new shoots have sufficient space to develop outward.

(3) Filling soil.

When planting, hold the leaves with one hand, add nutrient soil with the other, hold the base of the orchid plant and lift slightly upward to spread the root system, while shaking the orchid pot. Let the growing medium go deep into the root zone; continue adding soil and shaking the pot, adjusting the position and height of the orchid plant. Press with the hand along the pot edge, but never too hard to damage roots. Continue adding soil and pressing until the pot surface soil is 2-3 cm above the pot rim, slightly mound-shaped. The growing medium should cover all orchid roots, up to the base of the pseudobulbs. Regarding the depth of soil filling, tradition holds: Cymbidium goeringii should be shallow, Cymbidium faberi should be deep, but generally not burying the leaf base on the pseudobulbs is the standard. When newly collected orchids grow in the wild, they leave clear markers on the plant at and below the soil surface, which can be used as a reference. The size of the flower pot should also match the size and number of plants; neither a large pot with few small plants, nor a small pot with many large plants. Generally, the number of plants should be such that after 2-3 years, they will just fill the pot. Plant size should match pot height. This is beneficial for growth and meets ornamental requirements.

(4) Top dressing.

After planting is completed, spread a layer of small stones or green moss on the pot soil surface, preferably high-quality moss from under trees. It is both attractive and helps regulate moisture, and also protects leaf surfaces from mud contamination, and prevents new shoots from being infected by pathogens in the soil and rotting at the core; in addition, it can reduce rainwater erosion of the pot soil and keep the pot soil loose.

(5) Watering.

After planting is completed, water for the first time. The pot soil must be thoroughly wet. Water droplets should be small, and the force should not be too strong. If placing in a water basin to soak, never soak too long. Once the pot soil is soaked, immediately take out the orchid pot, then move it to a shaded place for maintenance.

4. Post-planting care and management. Mastering orchid planting techniques is certainly important, but managing and caring for orchids well is even more difficult, hence the saying "three parts planting, seven parts care." Orchid care requires understanding the environment, accumulating care experience, and patience and carefulness. The most important thing is to understand the growth and development patterns of orchids: when they sprout, when they grow leaves, when they bloom, and when they go dormant. Then carry out care and management from the aspects of temperature, humidity, watering, fertilizing, ventilation, plant protection, cherishing leaves, and protecting flowers, and you will certainly be able to grow orchids well.

1. Cherishing leaves. Orchid leaves are soft and beautiful but not weak, upright but not stiff.

Orchids are moving and lovely, but good flowers do not bloom often, and when flowers fall, there is nothing to be done; but orchid leaves remain evergreen through all four seasons, forever full of vitality, giving people year-round enjoyment. The elegance of orchids is displayed in the flowers and also carried by the leaves.

And lush leaves are the prerequisite for good flowers. When leaves are healthy and lush, they produce abundant nutrients themselves, resulting in more and more beautiful flowers. If leaves are damaged while flowers are many, it is merely a sign of rapid decline. The key to cherishing leaves is first to control shade density, air humidity, appropriate water and fertilizer, and maintain good ventilation. Make orchid leaves lush and healthy, green and glossy. Also strengthen pest and disease control, prevent wind, rain attacks, and mechanical damage. In addition, preserve the leaf tips. The tips of orchid leaves are like sword tips, brush tips, and eyebrow tips, able to convey meaning and spirit. Losing leaf tips makes them appear abrupt and dull. The key to preserving leaf tips is to ensure the water and nutrients orchids need, with loose and breathable pot soil, so the root system is well-developed and intact, the plant grows vigorously, and no scorched tips occur. Some say that the sign of well-cultivated orchids is that the leaf tip can pass through the eye of a needle, meaning the leaf tip is intact and the tip is undamaged. Different orchid species have different leaf tip shapes: some are acuminate, some are obtuse and rounded, some are notched, some are upturned. Regarding leaf color, some orchid varieties have gold or silver tips (i.e., leaf tips are yellow or white), showing their preciousness and rarity. This is another layer of interest in leaf appreciation. In daily care, pay attention to protecting orchid leaves, be gentle and careful during operations, do not bump orchid leaves, and maintain their natural posture.

Carefully clean contaminated leaves, and spray water should not accumulate in the center of the leaf cluster. Promptly cut off withered yellow old leaves and diseased leaves. For partial cutting of orchid leaves, make a slanted cut at an appropriate spot, with the cut angle less than 30 degrees. Some also cut twice, but do not cut into a flat top.

2. Protecting flowers. After flower buds emerge, if there are too many, they consume excessive nutrients from the mother plant, hindering leaf bud formation and robust growth. Remove excess thin and small flower buds early, leaving one flower bud per orchid seedling.

Each pot should retain 3-5 flower buds. Appropriately retain flower buds based on orchid variety, pot size, and number of seedlings. To protect and develop precious varieties, all flower buds can be removed to let them multiply profusely. During the period from flower bud elongation to flowering, maintain moderate light, so that flower colors are bright and full, rich in luster and full of fragrance. If light is too weak, the flower colors will be pale and lack luster. Flowers that stay too long consume nutrients, hindering sprouting, leaf growth, and flowering the following year. Cymbidium goeringii flowers bloom for about half a month; after they fade, promptly cut off the flower scape. For Cymbidium faberi flowers, when the last flower of the inflorescence has been open for 1 week, cut off the inflorescence. When breaking off flower scapes, stabilize the leaf base with one hand, press the flower scape to one side with the other, and it can be broken off from the base and pulled out, or cut off. The removed flower stems can be placed in a vase and enjoyed for many days. Generally, orchids are not allowed to be pollinated and set seed after flowering, especially not very robust and precious varieties, otherwise it affects flowering the following year. If conducting hybrid breeding, carry out artificial pollination at the appropriate time. And carefully manage the mother plant to make its seeds full and mature.

3. Temperature. Most of China is in the temperate and subtropical zones, and orchids generally originate in places with mild and humid climates, relatively high annual average temperatures, and long frost-free periods. In Northeast and Northwest China, orchids are rarely cultivated, mainly due to temperature constraints. The northernmost distributed Cymbidium species in China are Cymbidium goeringii and Cymbidium faberi. Their distribution line has winter frost or short-term snow cover, and relatively high summer temperatures. But since orchids mostly grow in mixed broadleaf and coniferous forests or in bamboo forests, the trees block the summer sun and resist the winter cold wind; even in places covered by snow, the impact on orchids is not great, because snow actually protects orchids for overwintering, and the ground temperature under snow is generally not below 0°C. Our introduction and domestication of Cymbidium ensifolium and Cymbidium kanran has moved them 600-1000 km north from their original habitats, and on a large-scale ground planting basis. This shows that the survival ability and adaptability of orchids are still relatively strong. In Northeast, Northwest, and most of North China, winters are too cold, and outdoor orchid cultivation is unsuitable. From mid-to-late October to late April of the following year, about half a year, orchids need to be moved indoors or into greenhouses for cultivation. In the lower Yangtze River region, orchids also need to be moved indoors in winter or heated in sheds. In Fujian, Guangdong, Guangxi, Yunnan, Sichuan, Taiwan, China, and other provinces and regions, Cymbidium kanran and Cymbidium ensifolium generally do not need indoor overwintering in winter. In Jiangxi, Hunan, and parts of Sichuan, certain measures are still needed to protect orchids in winter.

Temperature requirements for orchids: The temperature for orchid seed germination is: 21°C-25°C during the day, 15°C-18°C at night. The temperature required for grown terrestrial orchid plants is 20°C-22°C during the day, 13°C-0°C at night.

During the winter dormancy period of orchids, the temperature can be lowered. For example, Cymbidium goeringii and Cymbidium faberi require a minimum nighttime temperature of 4°C-6°C in winter, and can even drop to 0°C. The plant leaves can even tolerate minus 2°C-3°C under dry conditions. Orchid flowers develop from flower buds, and flower bud differentiation is closely related to temperature and light. Predecessors did much research on orchid flower bud differentiation, concluding that: a low temperature of 12°C-13°C is sufficient for flower bud differentiation, and the relationship with day length is not very significant. But the more light orchids receive, the more pronounced the effect of low temperature on flower bud formation. Therefore, from late spring to autumn, placing orchids outdoors for cultivation is better for growth and development than indoors. The purposes of temperature regulation are mainly 3 aspects: winter cold protection, summer heat protection, and changing the flowering period. When winter temperatures are below 0°C, orchid leaves and flower buds are susceptible to frost damage, with leaves showing water-soaked black spots and flower buds wilting. If the temperature drops suddenly and sharply or there is an especially severe frost, the damage is even greater. But winter temperatures being too high is also not good, because orchids are in a dormant state in winter, and too high temperatures will interfere with dormancy. In summer, if the temperature is too high, orchids suffer from heat, leaves turn yellow, become rough and lack luster, and are susceptible to disease attacks, often with leaf bases beginning to rot. The flowering period of orchids is clearly affected by temperature. Under general conditions, appropriately raising the temperature can make them bloom earlier. For example, the flowering period of orchids under plain and urban cultivation conditions is often 15-30 days earlier than under original wild conditions. Using this biological characteristic, the temperature can be appropriately adjusted to advance the flowering period by half a month to one month. Especially for species that bloom in spring, flower buds are generally already formed in July-September of the previous year, and after passing through the winter dormancy stage, appropriately raising the temperature can make them bloom early, in time for the Spring Festival holiday. But it must be pointed out that raising the temperature must be done gradually. Experiments show that rapidly raising the temperature actually produces an inhibitory effect, delaying the flowering period.

Methods of temperature regulation:

Temperature has a great impact on orchid growth and development. Too high temperatures accelerate respiration, increasing nutrient consumption; too low temperatures decrease enzyme activity, reducing synthesis, and slowing growth and development. The important thing is that daily temperature differences and seasonal temperature differences must form, so that they can sprout and bloom. In temperature regulation for domestication and cultivation, we adopt the principle of approximating the original orchid habitat. In summer, double-layer shade netting is used to shade the orchid nursery, with obvious cooling effects. When the air temperature reaches 35°C, the temperature in the orchid nursery is only 31°C-32°C. In winter, plastic greenhouses are used for warmth. When the air temperature drops to 0°C, the inside of the plastic greenhouse can still maintain 6°C-8°C. The winter temperature difference is smaller than in the open field, which is beneficial for nutrient storage and prevents frost damage. Besides building soil orchid sheds and orchid rooms, temperature regulation can also be achieved by planting trees, shrubs, vines, and lawns around the orchid nursery. In summer, they can absorb part of the solar radiation heat, and in winter, they can slow the loss of heat from the ground and air. Taking lawns as an example, according to measurements, in winter, the air temperature over grassland is higher than over bare ground, with a maximum daytime difference of up to 4.4°C, helping to avoid frost damage; while in summer, the air temperature over grassland is much lower than over cement ground, beneficial for heat protection and cooling. In summer, spray or sprinkle clean water in the air, on the ground, on benches, and on orchid leaves. Because water absorbs some heat when evaporating, it can play a role in cooling and heat protection; similarly, expanding water surfaces nearby also has this effect, such as ponds, reservoirs, ditches, and water tanks. In greenhouses, curtains need to be hung on the glass to block light and heat. In hot weather, pay more attention to ventilation and strengthening air convection for heat dissipation, partially lifting shed coverings; in orchid rooms, open doors and windows to avoid heat accumulation. In temperature regulation, besides air temperature, also pay attention to soil temperature. Orchid roots grow in soil, and the temperature of the pot soil has a direct impact on their physiological functions. Under general conditions, soil temperature is positively correlated with air temperature. When air temperature is high, pot soil temperature also rises, but the change process is relatively slow. First, prevent direct sunlight from hitting the flower pots, which heats the soil and pot and burns orchid roots near the pot wall; also pay attention to ensuring water temperature is close to soil temperature when watering, not too different. There is another issue worth exploring, namely the relationship between artificial protection and the orchid's own adaptability. Like all plants, orchids have their adaptability to the external environment. They are not inherently delicate. Therefore, when orchid growers protect orchids from heat and cold, their measures should be moderate. Covering too densely and for too long will inevitably weaken their stress resistance. Our orchid nursery has introduced and domesticated Cymbidium kanran and Cymbidium ensifolium from 600-1000 km to the south. Besides taking protective measures, we also gradually let them enhance their stress resistance and adapt to the new environment.

4. Humidity. Humidity generally refers to relative humidity, commonly expressed as a percentage.

Orchids have no fibrous roots and even less root hairs, so their water-absorbing surface is small; on the contrary, orchid leaves grow in clusters. Leaf surface transpiration is relatively large, and only when the air is humid can the balance between water absorption and transpiration be maintained. In the growing season of orchid native habitats, rainfall is abundant, the air is humid, and relative humidity is above 80%; especially Cymbidium sinense grows beside streams, often with dense water mist, and relative humidity is around 90%. One important reason why orchid cultivation in the north is difficult is dry air. Generally, urban households and balconies are not easy places to successfully cultivate orchids, and insufficient humidity is also a major factor. When air humidity is low, orchid leaves are rough and dull; when air humidity is suitable, leaf surfaces are moist and green. Generally, the humidity required during the orchid growing season should not be lower than 70%, and in winter dormancy about 50%; nighttime air humidity should be higher than daytime. Humidity and ventilation are two relatively contradictory factors. Too much ventilation lowers humidity. In northern winter and spring, dry winds blow frequently and humidity cannot be maintained, which is unfavorable for orchid growth, so ventilation should be appropriately reduced.

Methods of regulating and increasing air humidity:

Plant many trees, bamboo, and grass around the orchid nursery. The root systems of these plants can absorb large amounts of water from underground, then evaporate it from the leaf surfaces above ground. They can also retain surface moisture, gradually transpiring it, increasing the water molecule content in the air, thereby increasing air humidity. When the ground is dry, sprinkle water on the ground, benches, and walls, which also has the effect of lowering temperature. You can also spray or sprinkle water in the air space or on leaf surfaces of the orchid growing area. But for leaf surface sprinkling or spraying, it is not suitable to do it at night. If leaf surfaces need sprinkling in the evening, make sure the leaf surfaces can dry before nightfall. In southern China, there are sometimes continuous rainy days, especially during the plum rain season when humidity is too high. Doors, windows, and coverings should be opened for ventilation. Orchids prefer warmth and moisture. When humidity is high and ventilation is good, orchids grow robustly; but when temperature is low and there is no ventilation, water vapor condenses into droplets, which is harmful to new shoots and easily causes disease, so low-temperature high-humidity conditions should be avoided. In our large-scale ground-planted orchid seedling beds, bricks are laid around, with green moss planted on top. Bricks and moss have strong water absorption and moisture retention capacity. This economical and convenient natural humidification measure is very effective.

5. Watering. Watering should pay attention to water quantity, water quality, water temperature, watering time, watering methods, and other issues.

In the classification of xerophytes, hydrophytes, and mesophytes, orchids belong to mesophytes and do not need excessive water, so pot soil should not be too wet. This is determined by the structural characteristics of orchid rhizomes. Orchid pseudobulbs are enlarged, with a cuticle layer on the surface, and epidermal cells are thickened to form stone cells, with vascular bundles scattered throughout the stem. Pseudobulbs can store nutrients and water and are not easily evaporated. Orchid roots are mostly fleshy, with the outermost layer being velamen tissue. The cells of the velamen tissue are elongated and polygonal. When velamen tissue cells mature, the protoplasm disintegrates, and the cell walls develop thickened stripes. The function of velamen tissue is to protect the cortex, absorb water, and reduce and protect against water loss from inside the cortex. Therefore, orchids should not be watered too frequently, and pot soil should not be too wet, to avoid root rot. In addition, from the perspective of orchid native habitats, orchids mostly grow on hillsides, both sides of ridges, and rock crevices. These places have good drainage and no water accumulation. It is precisely to adapt to such an environment that orchid rhizome structures are suited for storing and retaining water and nutrients.

Principles of watering orchids:

Must be based on the following conditions:

(1) Orchid species.

Epiphytic orchids and those with aerial roots can be watered less. For example, Cymbidium hookerianum has aerial roots and can absorb water from the air, so watering need not be excessive. Also, those with thick cuticles on leaves should be watered less. For example, Tiegu Su has a thick leaf cuticle, low water evaporation, and watering should be strictly controlled.

(2) Orchid growing season.

In spring, temperatures gradually rise, and it is the season for new shoots to sprout, so watering should be timely. Water once a day or every other day to keep the pot soil moist. During this period, water shortage will delay flowering and make shoots weak. In summer, temperatures are high, water evaporation is large, and it is the period of leaf expansion, root emergence, and root and leaf elongation. Water once every morning, and in the evening if the pot soil is dry, add some water to moisten the pot soil, thoroughly moisten the leaves, lower the temperature, reduce nutrient consumption, and facilitate growth and development. Entering autumn, temperatures gradually drop, orchid growth slows, and observe the pot soil moisture daily: water when dry, leave alone when moist. In winter, orchids enter dormancy. Pot soil should be slightly dry, and watering should be reduced or omitted, but pay attention to the pot soil, preventing the pot soil from losing too much water and instead drawing water from within the roots. At the turn of winter and spring, after Cymbidium goeringii buds form, flower buds begin to elongate, so the pot soil should also maintain a certain humidity. If the pot soil is too wet in winter, the water content of the orchid plant increases, which easily causes frost damage.

(3) Orchid growth condition.

Orchids with strong growth and good roots can be watered more; conversely, reduce as appropriate, and for diseased plants, control water even more. When orchids are sprouting and growing, water can be more; after sprouting, gradually reduce. As new shoots gradually mature, water should again be less; when flower buds appear, slightly more water; but during the flowering period, water should not be too much, to extend the flowering period. After flowers fade, stop watering for several days, letting the pot soil become slightly dry, letting the orchid rest briefly, then water again.

(4) Pot and plant conditions.

That is, water according to the texture and size of the flower pot. Clay pots and large pots get more water; porcelain and glazed pots get less. Potted plants with many plants or densely planted ground orchids get more.

(5) Pot soil moisture condition.

The basis for watering, including season, plant, weather, flower pot, and soil quality, can all be comprehensively reflected by the degree of pot soil moisture, so pot soil moisture is the direct and intuitive basis for watering.

This can be judged by observation and touch. If the potting soil becomes hard, its color turns lighter, and the moss on the surface of the pot is dry and wilted, it indicates that the soil is dry. Water should be given immediately. If the potting soil is dark in color, feels damp, and the moss grows mold, this indicates that the soil is too wet and should not be watered. Generally, a soil moisture content of 15%-20% is appropriate.

(6) Watering time.

Generally speaking, in spring and autumn it is best done in the morning; during the hot midsummer period it is best done around sunrise and around sunset; in early winter and early spring, water after the sun is directly overhead and the temperature has warmed slightly. During the period when the plants are brought indoors to overwinter, watering must be done at noon on clear days. However, care should be taken to avoid wetting the leaf surface or letting water seep into the leaf sheaths. Among the folk there are some very valuable experiences regarding watering orchids; for example, for Cymbidium goeringii (spring orchid) and Cymbidium faberi (Faber's cymbidium) there is the experience of "not dry in autumn, not wet in winter, fond of moisture in spring, fond of slight dampness in summer and autumn, and needing moisture with a touch of dryness in winter." This shows that orchids have different water requirements at each stage of growth and development, and management should be adapted to local conditions and carried out flexibly. Generally, after the Beginning of Spring, the climate gradually warms, the flower buds begin to swell, and the soil should be kept moist, with a spraying of water every 2-5 days. After the Awakening of Insects, for flowerless Cymbidium goeringii and Cymbidium faberi grown in the open, the wind and sun tend to dry out the water in the pots, so daily watering should be frequent, but the amount of water should not be too much; water once every 2-3 days or a small amount once a day. After the Beginning of Summer, for all orchids that have finished flowering (including Cymbidium kanran and Cymbidium sinense), the soil should be slightly drier, because after flowering most have a brief dormant period, grow slowly, and evaporate less water from the leaves. From June onward, as the weather gradually heats up, the daughter plants (that is, young shoots) grow faster, and at this time more attention should be paid to soil moisture; often spray the orchid leaves and the orchid bench with clean water to create a small moist microclimate, which is beneficial for the daughter plants to elongate and unfurl their leaves. During the plum rain season, watering should be controlled to reduce the occurrence of disease; leaf-art varieties and some petal-type seedlings are even more prone to disease, so even more attention should be paid. During the dog days the climate is hot, so in addition to strengthening shading, the soil moisture must also be carefully maintained, and clean water should be sprayed on the leaves and the pot surface every day around sunrise and sunset. After White Dew it gradually turns cooler, and with the nourishment of night dew, the growth of new plants pauses and the orchid buds break through the soil and grow slowly; at this time the amount of irrigation can be reduced; but when the potting soil is found to be dry, it must be watered until moist. In late autumn, the new plants have turned from fresh green and tender green to deeper and darker shades. The flower buds and their sheaths are all visible, and it is necessary to prevent prolonged rain and excessive moisture to reduce sheath rot (that is, rotting of the bud sheaths); measures should be taken to shelter from rain and to receive more sunlight.

(7) The water quality and water temperature for watering.

For watering orchids it is best to use collected rainwater, which is the cleanest and also neutral; river water is next; well water contains minerals and is mostly alkaline, so it is relatively poor; tap water contains disinfectants and is the least suitable for orchids. If tap water must be used, it should be stored in a reservoir for more than 24 hours, and exposure to sunlight is even better, so that after the disinfectants settle out or decompose, the clear water on top can be taken to water the orchids. Besides this storage treatment, there is also an activation treatment, which is to keep fish, algae, chlorella, rhodophyta and other aquatic organisms in the reservoir where tap water is stored, in order to improve the water quality. But care must be taken as to whether the fish have diseases, to prevent them from contaminating the water quality. The temperature of the potting soil can directly affect the water-absorbing function of the orchid roots. Therefore, the temperature of the irrigation water should be very close to the potting soil temperature and the air temperature. In hot summer, after the flower pots and soil have been heated by direct sunlight, if cold water is suddenly poured on them, the temperature difference between the two is too great, which will disrupt the normal absorption function of the root system and affect the physiological balance. So in summer, when watering orchids, it is best to do so in the morning and evening, when the water temperature is close to the soil temperature. The reservoir or water tank is best half buried in the soil, and with shading added, the water temperature in summer will not become too high.

(8) Watering methods.

The commonly used orchid watering methods include pouring, spraying and soaking. Usually a watering can, a ladle or a hose is used for watering; when watering, pour slowly from the edge of the pot so that the water gradually seeps downward and toward the center, and never pour it abruptly into the center of the leaf cluster, nor let the water splash up the potting soil and dirty the leaves. Spraying should soak through the whole pot, and one should not give only a half watering, that is, with water only in the surface layer while the lower layer gets none; if half waterings are given for a long time, then the surface is wet while the interior is dry, causing some orchid roots to be unable to absorb water for a long time and to shrivel, while the upper orchid roots instead turn upward and grow, sprawling and curling in disorder in the surface soil. To save trouble and effort, many people connect a rubber hose directly to the tap and irrigate the orchid pots, which is very harmful: first, the tap water has not been treated, and the bleaching agent is harmful to orchids; second, the water temperature and soil temperature differ greatly; third, watering cannot be differentiated according to different situations. The spraying method is to spray water on the leaf surface with a spray can, which can both increase air humidity and soil moisture and wash away dirt on the leaf surface; this method is often used during the orchid growing season. Do not spray too much each time; the standard is that the leaf surface is wet but water does not run off. If too much water is poured into the heart of the leaves and remains there for a long time, it will rot the new shoots. The nozzle holes of the spray can should be fine and dense, and the water droplets fine and even. The soaking method, also called seep-watering, is to place the bottom of the orchid pot into shallow water and let the water gradually moisten the potting soil. The soaking time must not be too long; as soon as the surface soil is seen to be moist, immediately take the orchid pot out. This method can keep the orchid leaf surface clean. In dry seasons, the orchid pot can also be placed in a shallow water tray, and the flower pot absorbs the accumulated water in the tray, which then infiltrates the potting soil, thus maintaining relatively stable soil moisture. The disadvantage is that the bottom hole of the flower pot is blocked by water, and air permeability is affected to a certain extent.

6. Light and sunshine. Light refers to the quality and quantity of sunlight, including the wavelength of light, spectral composition and light intensity. Sunshine refers to the duration of sunlight; generally, irradiation of more than 14 hours is long-day, and less than 14 hours is short-day. Among plants, those that need long days to flower are called long-day plants; conversely, those that need short days to flower are called short-day plants. Light and sunshine are closely related to the growth and development of orchids.

Orchids' requirements for light:

A floral proverb says: shade for camellias, sun for peonies, half shade and half sun for the four-season orchid. This shows that different flowers and trees have different sunshine requirements, and orchids need half-shade, half-sun light conditions. The effect of light on leaf color -- orchids have long grown in mountain forests and have developed a shade-tolerant habit, and do not like direct strong light. When light is too strong, the leaf color turns pale green; if suddenly exposed to strong light, the leaf color quickly turns yellow, the leaf surface becomes rough, and the leaves may even scorch. With moderate light, the leaves are green with a fine texture and luster; with too weak light, the leaf color is dark green and loses its luster. The effect of light on sprouting -- the strength of light has a direct impact on the number of leaf buds and flower buds, the time they emerge from the soil, and their growth condition. With too weak light, orchids produce many leaf buds and few flower buds, and their growth is poor. Therefore, appropriately increasing light for a period before flower bud formation can promote flower bud differentiation and achieve the goal of more flowering. The effect of light on flower color and flowering -- the flower color of orchids is mainly determined by flower pigments, and the violet light and ultraviolet light in light are the main light energy forming orchid pigments. Therefore, when light is strong the flower color is deeper and more vivid; when light is excessively weak the flower color is extremely pale, and compared with normal it may be mistaken for another variety. For example, in ancient times in Ningbo, Zhejiang, there was a kind of snow orchid produced on shaded, north-facing slopes; if planted in a pot and given a little sun, it would turn green, and so it was regarded as rare and precious, yet today it is often encountered during collection in the wild, and can also be obtained through artificial cultivation. Some people use this to commit fraud and pass it off as a new variety, and those with insufficient experience are often deceived. If other conditions are the same, then orchid pots placed in a position with stronger light bloom first; this is because the accumulated illumination and accumulated temperature first reach a certain value. Some people have experimented and found that prolonging the light duration to 14-16 hours can promote earlier flowering of medium-sized plants and small seedlings; but for mature orchid plants, a light duration of no more than 8 hours can promote flowering. For orchids that bloom in winter, short days and long nights and low-temperature conditions must be provided to promote flowering. For orchids that bloom in summer, long days and short nights and high temperatures are required to promote flowering. For orchids with flower buds, to promote earlier flowering, light can be appropriately prolonged and temperature increased. In a small room, a 100-watt bulb can raise the room temperature by 3°C-5°C, which can promote earlier flowering. The relationship between light and leaf art -- leaf art refers to the cultivation technique in which lines or spots appear on the leaves. Leaf art is related to light. Changes in light can be used to promote changes in leaf art. The method is to use robust growing orchid seedlings, with more than three plants connected together; before 9 o'clock in summer and before 10 o'clock in winter, expose the orchid pot to sunlight, insert a thermometer into the pot, and when it has been sunned to 30°C move it into the shade. When it drops to 25°C, move it out again into the sunlight. Repeat this over a long period. One shade and one sun, one cold and one hot, is beneficial for the appearance of variable factors within the leaves; over the years, hard work pays off, and variegated leaves may appear. But this must be premised on the existence of recessive factors for leaf art within the orchid leaves; the change in sunlight merely promotes their manifestation.

Basis and methods for regulating orchid light:

Liking half-shade and half-sun light is a common characteristic of most Cymbidium plants, but there are also differences among species. Spring-blooming species, such as Cymbidium goeringii, Cymbidium goeringii var. longibracteatum and Cymbidium goeringii 'Songchun', need relatively weaker light, and the shading degree should be controlled at 70%-80%. Summer- and autumn-blooming species, such as summer cymbidium and autumn su, need slightly stronger light, and their shading degree should be controlled at 60%-70%; Cymbidium sinense needs about 85%. The light duration and intensity of the four seasons, spring, summer, autumn and winter, are all different, and should be treated separately and the shading degree adjusted well. Within a single day, morning and evening sunlight can be allowed to shine on them, while the fierce midday sun must be blocked and regulated, and on cloudy days the shading degree should be reduced. It is worth noting that after summer rainstorms, or when it first clears after long rain, orchid pots must absolutely not be exposed to the sun; the experience of predecessors: if exposed to the sun right after rain, the water in the pot is hot, and it will scald the leaves and injure the roots. Although orchids are relatively shade-tolerant, they also have phototropism; in the same cultivation site, the flowers and leaves on the sunny side are always somewhat more luxuriant. Over time this makes the growth of flowers and leaves uneven, and they lean to one side. For symmetry and beauty, the direction of the orchid pots should be rotated and adjusted at intervals. If for a special need of modeling or composition, in order to express a particular poetic feeling and artistic conception, the position of the light source can also be used to strengthen the tendency of flowers and leaves, achieving the beauty of dynamic balance, which can satisfy appreciation needs. To regulate the shading degree and light duration, there are usually the following methods: Buildings -- establish greenhouses, orchid pavilions, waterside pavilions and orchid corridors to place orchids, and use the light-transmitting and sun-shading properties of such buildings to regulate light. As long as the orchid pots are placed appropriately, the expected effect can be achieved; in the sunny places of these buildings, bamboo blinds or shade nets can be hung for regulation. For potted orchids kept on balconies, light is regulated by carrying them in and out; although this is hard and tiring, it also cultivates enjoyment, and growing flowers combined with fitness is a pleasure within it. Building sheds -- shade sheds can be built with bamboo, wood, angle steel and the like as frames, covered with bamboo blinds, plastic film, shade nets, etc. Our method of regulating light intensity is to use bamboo to build frames in the orchid nursery, on which are set double layers of shade nets with a 50%-70% shading rate; the upper layer is relatively fixed and is only rolled up in winter, while the lower layer can be put down or taken up. In midsummer use the double layer; in spring and autumn use a single layer; at noon on clear days in summer and autumn use the double layer, and on cloudy and rainy days a single layer. In winter it depends on the situation; on clear days put down the lower layer, and on cloudy days roll up the lower layer, because in winter the light change inside the plastic greenhouse must not be too great, as too great a change will cause temperature and humidity to change accordingly, which is unfavorable for orchid dormancy. In addition, before the orchid flower buds are ready to bloom, they must receive moderate scattered sunlight, otherwise the flower color will be dull and not show its beauty. Building trellises -- on the orchid cultivation site, build bamboo trellises, wooden trellises or reinforced concrete trellises, and let grape, honeysuckle, morning glory, trumpet creeper, cypress vine and other vines climb and spread over them, which can both shade and be beautiful and practical. Deciduous vines shade in summer and let light through in winter, which is a natural regulation. Planting trees -- around the orchid nursery, select and plant evergreen trees of different heights, deciduous trees, bamboos, etc. in matching arrangement to regulate light intensity.

7. Fertilization. Orchid roots have no fibrous roots, and within the roots there is a symbiotic fungus.

The root fungus absorbs mineral nutrients from the outside and supplies them to the orchid, while the orchid root cells provide water and organic nutrients to the root fungus, forming a mutually beneficial symbiotic relationship in which they coexist. But a stable balance must be maintained between them for lush growth. Preparing suitable nutrient soil and fertilizing appropriately to maintain the balance between the two can promote vigorous orchid growth. Previously some people thought that since orchids grow in the mountains and are naturally refined, clear water and fresh air would be enough to sustain them. Others loved orchids too deeply and were too impatient, often applying heavy fertilizer with high potency and high concentration, producing results contrary to their wishes. Therefore we must seriously explore scientific and reasonable fertilization.

(1) Types of fertilizer.

Fertilizers can be classified by their effective components, their nature, and their method of use. By effective components, fertilizers are mainly nitrogen, phosphorus and potassium fertilizers. Nitrogen is a major component of the cell nucleus and proteins, and is also an indispensable element in forming chlorophyll. Nitrogen fertilizer can make orchid leaves luxuriant and robust; conversely, the leaves droop and soften, sprouting is difficult, and the reproduction rate is low. Commonly used nitrogen fertilizers include compost, human and animal manure and urine, urea, green manure, ammonium sulfate, ammonium nitrate, etc. Phosphorus is also a major component of the cell nucleus, and within plant cells directly affects cell division, chlorophyll formation and protein synthesis and transformation; it can promote flower bud differentiation and growth, and bring about larger flowers, fresher color and stronger fragrance. Commonly used phosphorus fertilizers include superphosphate, monopotassium phosphate, phosphate rock powder, bone meal, rice-washing water, etc. Potassium directly participates in photosynthesis, can make cell physiology normal, and is also related to the synthesis of carbohydrates, proteins and fats. Potassium fertilizer can make orchid stems, leaves and roots grow robustly, make the leaves tough and not easily broken, and enhance cold resistance and disease resistance, and can also increase the fragrance of the flowers. Commonly used potassium fertilizers include plant ash, potassium sulfate and monopotassium phosphate, all of which are fertilizers relatively rich in potassium. Besides the three main elements nitrogen, phosphorus and potassium, orchids also need various trace elements such as calcium, magnesium, iron, boron and zinc; these can be satisfied in the prepared culture soil and generally need not be added separately. But the demand for nitrogen, phosphorus and potassium is relatively large and must be solved through fertilization, repotting and changing soil. By the nature of the fertilizer, it can generally be divided into organic and inorganic fertilizers. Organic fertilizers include compost, green manure, barnyard manure and cake fertilizer. Before use, organic fertilizer must be fully fermented, and the fermentation time must be at least more than one month. Organic fertilizer can improve soil structure, increase soil humus, make the soil well aerated and water-retentive, and its fertilizer effect is also long-lasting, continuously decomposing long-acting nutrients for the orchid to absorb. Inorganic fertilizer is also called chemical fertilizer; its nutrient content is high, it is clean and odorless, it does not need fermentation and can be diluted for use immediately, it is convenient and its fertilizer effect is quick, but it does not last long, and long-term use can deteriorate soil structure. Generally orchid growers oppose the use of chemical fertilizers. In fact, if orchids are mainly given organic fertilizer and chemical fertilizer is used in combination, the effect is still very good. By method of use, fertilizers can be divided into base fertilizer and topdressing. Base fertilizer is the fertilizer added to the soil when preparing the culture soil or before planting, such as leaf mold, grass compost, and sweet potato chaff soil; these are both the substrate for cultivating orchids and base fertilizer. Silkworm droppings, human manure, cow manure, bone meal, hair, cake fertilizer and the like can all be used as base fertilizer added to the bottom of the pot or turned under the soil as base fertilizer, but chicken manure and human waste are taboo.

(2) Topdressing is fertilizer applied after the orchids are planted, during their growing season.

Generally orchids are only repotted and the soil changed after 2-3 years of planting, and nutrients must be replenished in the meantime, so topdressing should be applied.

Time of fertilization:

During the spring and summer growing period of orchids, to make the orchids grow robustly and vigorously, more nitrogen fertilizer can be applied. If it is a leaf-art variety, then apply less nitrogen fertilizer or none, because a dark green leaf color will affect the appreciation effect of the leaf art. Do not fertilize when the summer temperature is above 30°C, because the potting soil temperature is relatively high, water evaporates too quickly, and the concentration of residual fertilizer increases, which is harmful to growth. If fertilizer is applied too frequently in summer, it easily stimulates autumn shoots, and the plants that grow later will be short and weak, and the next year's spring shoots will be inhibited as a result. Do not fertilize when the temperature is below 10°C, because at this time the plant is in a semi-dormant state and does not absorb nutrients. Fertilizer should be applied only when sunlight and temperature are suitable and photosynthesis is vigorous. In winter orchids are in a dormant state, so there is even less need to fertilize. From before the orchid's new shoots grow to half-maturity from the pseudobulb, and around the time the leaf buds emerge from the soil and during their extension period, this is the vegetative growth stage of the orchid, and slightly more nitrogen fertilizer should be applied, while phosphorus and potassium fertilizer should be less. After vegetative growth comes reproductive growth; the nutrients produced by photosynthesis are stored in the pseudobulbs and leaves for use in flowering or new shoot growth. At this time more phosphorus and potassium fertilizer is needed; applying appropriate phosphorus and potassium fertilizer can promote the pseudobulbs to become plump and mature, and to produce shoots and flowers. If the orchid leaves are pale and yellowing and the plant is weak, it is mostly caused by a lack of fertilizer, and topdressing should be applied in time. But sometimes leaves also turn yellow due to excessively strong sunlight. Diseased plants should not be fertilized; wait until the disease is cured and the plant has recovered before fertilizing. Robust orchid seedlings can be helped to grow by applying more fertilizer.

Ancient orchid growers had this experience:

Never suddenly fertilize a thin orchid. Never leave a fat orchid thin for long. This means that a thin orchid that has never been fertilized cannot suddenly be given strong fertilizer, for it cannot absorb it and it will be harmful. For orchids that are regularly fertilized, one also cannot go a long time without fertilizing. In short, uneven fatness and thinness is not beneficial to orchids. Usually Cymbidium goeringii, Cymbidium faberi and Cymbidium ensifolium begin to be fertilized in early May. In summer during the dog days, and in winter from December to early February of the following year, no fertilizer is applied. From May onward, apply a dilute fertilizer once every 2-3 weeks until the end of September. In early September apply a dilute fertilizer once to Cymbidium goeringii, and in late September fertilize Cymbidium ensifolium once. After each fertilization, clean water must be added the next morning, which facilitates absorption by the orchid and also prevents damage to the orchid roots from improper concentration. Generally, fertilization is not suitable around the time of flowering.

(3) Fertilization methods.

Fertilization must mainly use organic fertilizer, which can make the soil loose with good structure and is beneficial to orchid growth. One should also apply thin fertilizer frequently, that is, the experience of predecessors that it is best to be frequent and dilute, and one must absolutely avoid sudden and heavy application, which is what today's people mean by small amounts and many meals. When applying, dilute the water and fertilizer appropriately, then pour it around the roots with a watering can, and do not contaminate the orchid leaves. If chemical fertilizer is used, the concentration must be even lower. During the orchid growing season, a water solution of 2‰ urea and 2‰ monopotassium phosphate can be used as topdressing 2-3 times.

8. Ventilation.

Ventilation is also very important in orchid cultivation and management, yet it is often neglected by people. 146 Zhuhong Xinsu (Beijing). Good ventilation, continuously supplying orchids with sufficient fresh air, can promote photosynthesis, increase nutrient production, promote metabolism, and make orchids luxuriant. Ventilation in the orchid room and shade shed can regulate their temperature and humidity, making them beneficial to orchid growth, and can also reduce the occurrence of pests and diseases. Orchid brown spot disease and southern blight often occur in poorly ventilated environments. The orchid planting site must be open, the terrain should be slightly high, the flower bench should not be too low, and attention should always be paid to ventilation. Orchids like gentle and mild breezes and do not like sharp winds; excessively cold or strong winds should be avoided by every possible means. Orchid pots should be placed sparsely rather than densely, and sufficient distance should be kept between pots so that the leaves are not damaged by friction when the wind blows. If the site is small, the flower bench can be built into a stepped shape, which facilitates ventilation and is also convenient for management and viewing. Each orchid pot should not contain too many or too densely packed plants. If the plants have multiplied too densely, they should be repotted and divided in time. Often clear away weeds in the orchid pot, diseased leaves and fallen leaves from trees and other debris, in order to facilitate ventilation within the pot. Daily work for ground-planted orchids throughout the four seasons: in spring, around Qingming, remove the plastic film from the greenhouse, then water thoroughly once; several days later apply once a 15-20 times diluted duck feather water or fertilizer water made by fermenting cake fertilizer. At the same time, spray once with 1‰ omethoate (containing 40% effective ingredient) to kill insects. From May to July, apply once a month a fertilizer water made with 5% duck feather water or cake fertilizer. In August apply once a 3‰-5‰ compound fertilizer. After the beginning of autumn, no more fertilizer is applied. Autumn management is extremely important; we summarize it in two words: autumn tempering. That is, after the beginning of autumn, orchids are no longer fertilized, water is controlled, and light is increased, to prompt early maturity. Generally potted orchids should follow the golden rules of orchid growing: do not take them out in spring, do not expose them to the sun in summer, do not let them dry out in autumn, and do not let them get wet in winter. But ground-planted orchids are not necessarily so; in autumn it is better to keep them dry than wet. The reason is: although the air is dry in autumn, there is still ground warmth rising in the soil, so there will not be severe water shortage; moreover, drought can exercise the orchid's cold resistance and prepare it for overwintering. Autumn tempering can prompt nutrients to gather toward the pseudobulbs, increase the protoplasm concentration of the pseudobulbs, lower the freezing point, and prevent freezing injury. If the orchid seedlings grow vigorously in autumn, and then a cold wave comes and the temperature drops sharply, they will inevitably suffer freezing injury. Ground-planted orchids cannot be moved indoors before the severe winter arrives, so only through autumn tempering can they survive. November is a relatively busy season in the orchid nursery; the main work is to prepare for the orchids' overwintering. First, remove the upper shade net, then install the plastic greenhouse; do not close the two ends of the greenhouse at first, and only close them when the temperature drops obviously, and open them for ventilation at noon on clear days. This month, spray once with 1:1 Bordeaux mixture. When the severe winter season arrives, first, one must not water easily; second, moderately increase light. Moderate means that in winter some clear days have relatively high temperatures, especially with the warm winter phenomenon in recent years; at this time the lower shade net should be spread down so that the temperature in the greenhouse does not rise or fall abruptly. If the shade net is not put down, and the temperature in the greenhouse reaches 18°C-22°C for several consecutive days, some new shoots will begin to sprout, and once a cold wave arrives and the temperature drops sharply, they will certainly be frostbitten. Therefore, in winter a dormant environment must be created for orchids, and dormancy must not be easily broken. In early spring, cold and warm air masses are frequently active over the land, and management must be even more careful, otherwise orchid seedlings that have consumed nutrients through the winter are very likely to turn yellow and wither. Gradually and moderately increase light; the plastic film must not be removed too early, and it can only be removed after the weather in early April has become clear and stable.

1. Potting soil requirements: a neutral to slightly acidic soil containing a large amount of humus, loose and well drained is best, with a pH generally around 5.5 to 6.5. In Sichuan, Emei Xiantu and "Xinghong brand" refined orchid potting medium are mostly used, and more commonly "bamboo root soil" and leaf mold from moist broadleaf forests in mountainous areas are used to cultivate orchids.

2. Placement site: orchids can be cultivated outdoors and on balconies in spring, summer and autumn, and a place with good ventilation, moist air and no environmental pollution should be chosen. Being near a pond or riverside is of course good, but at least there should be tall trees or bamboo groves and shade nets to reduce sunlight exposure and lower the temperature. Orchid pots are best placed on wooden frames (or steel frames); if placed on the ground, bricks should be used as a base. In a home balcony, a small galvanized iron water tank can also be used to store water with bricks placed on top for cultivation, increasing humidity.

3. Appropriate shading: most orchids belong to semi-shade plants, and most species are afraid of direct sunlight and need appropriate shading. In early to mid-April, the net can be removed and windows opened, giving more sunlight to promote growth. In May, apart from the midday sun, they can receive 6 hours of sunlight; from June onward, shade all day, and after October, apart from the midday sun, they can be kept fully open. Remember the proverb: "More shade, better leaves; more sun, better flowers."

4. Reasonable fertilization: orchids are naturally "vegetarian," and fertilization should depend on the chosen potting soil and growth condition. Those growing luxuriantly and without disease can be fertilized, while those growing poorly should not be fertilized or only lightly fertilized. Newly planted orchids whose roots have not fully developed should only be fertilized after 1-2 years. Generally in June-July, when the orchid leaf buds have extended about 1.5 cm, apply a decomposed liquid fertilizer once every three weeks (the concentration should preferably be dilute, about 10%). Chemical fertilizers are taboo; do not fertilize in high-temperature seasons. From August to September, apply a diluted liquid fertilizer once every two to three weeks. Each fertilization of orchids should be done in the evening, and clean water should be poured in the morning, called "return water."

5. Appropriate watering: rainwater and spring water are best for watering orchids; tap water or rice-washing water should be left overnight before use. When watering, pour from the edge of the pot, and do not pour into the flower buds. The amount of water should be determined according to the temperature, the dryness and wetness of the potting soil, and the growth condition of the orchid. Water more when there are many leaves, and less when the leaves are fine. In April-May, when the new buds have not yet emerged from the soil, the potting soil should be somewhat dry, as too wet will easily rot the new buds; June-September is the growing period for orchid new buds, and the amount of water should be increased, watering once every morning on clear days or once a day, and absolutely avoid watering under the fierce midday sun. In autumn, reduce the amount of water appropriately; leaf-surface misting can be used, and keeping the potting soil moist is best. In winter, the amount of water should be controlled even more, keeping it at "80% dry, 20% wet" as appropriate.

6. Evening misting: orchids originally grow in an environment with moist air, so in dry seasons, in addition to shading, evening misting must also be done to increase air humidity and lower the temperature; water can also be poured on the ground (bench surface) where the potted orchids are, as "one cold and one hot" can further stimulate orchid growth.

7. Wind and rain protection: the "February ghost wind" causing old leaves to yellow and fall is a normal phenomenon, and dead branches and withered leaves can be cut away. Orchids can be exposed to light rain, but must avoid moldy rain, rainstorms or continuous rain, otherwise the heart and leaves are easily rotted. In rainy seasons, a small amount of plant ash can be appropriately scattered.

8. Pruning and flower removal: during orchid cultivation, withered, yellowed and broken leaves and diseased leaves should often be cut away to facilitate ventilation. For precious orchids, if there are too many flower buds, keep only the strong buds, with 1-2 flower buds per pot as appropriate. Cymbidium goeringii flowers should be removed half a month after blooming, and precious orchids should be removed after 7 days, so that the spring leaf buds grow robustly and bring better flowering the following year. For summer orchids, when the last flower on the inflorescence has been open for a week, cut it off 3 cm above the pot surface.

9. Cold protection and warmth: because orchid varieties differ and their places of origin vary, their cold resistance also differs, so the time to bring them indoors in winter and the position to place them indoors also differ. Cymbidium kanran, autumn orchids and Cymbidium sinense grow in the south and should be brought indoors (or have windows closed and nets drawn) when the temperature is 5°C, and placed as far as possible in a south-facing sunny spot. Spring and summer orchids have strong cold resistance and can be brought indoors only when the temperature reaches 0°C, and placed on the northeast side. Around noon on clear, windless days, windows should be opened on the south or southeast side, and nets drawn for ventilation. Autumn orchids must not have windows opened on clear days at 1-2°C. Of course, if there is a greenhouse, electric light can be used for heating.

10. Disease and pest control: the potting soil should generally be sterilized (exposure to the hot sun can also work) to prevent disease. Orchids are most prone to southern blight in rainy, high-temperature seasons; for a small amount, it can be brushed off with a damp cloth, and for many pots, 500-800 times Bordeaux mixture or thiophanate can be used, sprayed once every 7-10 days. Among pests, scale insects (commonly known as "orchid lice") occur most; during the hatching period use a 1000 times solution of 1% omethoate and 25% phosmet emulsifiable concentrate, spraying once a week. To treat the symptoms one must also treat the root cause; pots should be placed at appropriate density, arranged high and low, increasing air circulation and ventilation, to reduce the occurrence of disease.

However, different orchids have different cultivation methods.

Several aspects to note in orchid cultivation

Our country has a long history of orchid cultivation, and our predecessors have accumulated rich experience in orchid growing for us. We should thoroughly understand the experience of our predecessors, absorb its essence, and deeply recognize that: cultivation environment, potting medium, watering, fertilization, and the prevention and control of pests and diseases are the five major links in orchid cultivation and management.

1. The choice of environment is relatively important. Cymbidium faberi mainly grows under shrubs in subtropical mountain forests, and has developed the growth habit of liking half shade and half sun and liking moisture and ventilation. As long as the growth rules of orchids are mastered and environmental conditions close to those of orchids are provided or created, all parts of the country are suitable for cultivating Cymbidium goeringii and Cymbidium faberi.

2. Use of potting medium. According to cultivation experience in various places, as long as it is slightly acidic, no matter what potting medium is used (including soilless cultivation), orchids can be well grown; the problem is that different potting media should be managed by different methods. Flower pots are best made of earthenware pots or Yixing clay pots, because orchids are aerial-root plants and air permeability of the pot is very beneficial to orchid growth.

3. Reasonable watering is the key to growing orchids well. The water for watering orchids must be clean and slightly acidic, and water containing disease-causing bacteria must never be used. The watering method should vary with different plants. Loose mountain soil holds sufficient water, and granular soil plus porous volcanic rock also absorbs water relatively fully without accumulating water. After different potting media have been given one thorough watering, when the pot surface is seen to be dry and about one centimeter of the potting medium has turned white, water can be sprayed on the pot surface to increase air humidity, increasing the moisture in the upper part of the potting medium so that the orchid and pseudobulbs maintain a certain moisture; then when the whole pot is not yet dry from top to bottom, water heavily and thoroughly again.

4. Fertilization: on the basis of mastering watering well, in order to promote better growth of the orchid, fertilization becomes even more important. Organic fertilizer, that is, farmyard manure, should be dilute and can be applied once every ten-odd days; other inorganic fertilizers (chemical fertilizers) should be used according to the instructions. During the orchid growing season, foliar fertilizer can be applied as a topdressing outside the roots. Base fertilizer is also very important; when repotting and changing soil, an appropriate amount of base fertilizer can be added as long as the fertilizer does not touch the orchid roots. Too much fertilizer easily burns the orchid roots and causes black spots; if fertilization is proper, it can produce strong seedlings and good flowers. The general requirement for fertilizing orchids is a small amount, clear, dilute and light, truly achieving thin fertilizer applied frequently.

5. Pest and disease control: insect pests are easy to prevent, while fungal diseases are hard to cure. If scale insects and other pests are found on the orchid, omethoate or decis can be used for spraying according to the instructions, and it is best to use them in combination, 2-4 times a year. General fungal diseases such as black spot can also be treated; fungicides such as copper hydroxide, thiophanate-methyl and chlorothalonil can be used according to the instructions, with regular alternating treatment and preventive spraying every 15-20 days during the growing season. If ophistoma soft rot (rot coccus disease) is found, it is an incurable disease in orchids and cannot be cured at all; once found, remove it in time. Therefore, when purchasing orchids, one must pay attention and absolutely not buy lower-priced diseased plants and bring them home, thereby affecting other precious orchids.

Different orchid species have different temperature requirements. For Chinese orchids, the most suitable temperature for vegetative growth is 20-30 degrees, the adaptive temperature is 5-35 degrees, and the temperature during the reproductive period is generally between 5-15 degrees. At night it is 3-5 degrees lower than during the day. When the summer temperature is above 30 degrees, the higher the temperature, the more orchid growth is hindered. But under ventilated conditions, Chinese orchids are not harmed by short periods of high temperature up to 35-42 degrees. When the temperature is below 12 degrees, growth is slow. When the temperature is below 12 degrees, Chinese orchids shift to reproductive growth. Cymbidium sinense originally grows in subtropical mountain forests; in summer, the daytime temperature can reach about 32 degrees, while at night it is cooler, with the temperature generally not exceeding 20 degrees, and the winter temperature does not drop below 10 degrees. Cymbidium kanran and Cymbidium ensifolium originally grow in mountain forests transitional in the subtropics. Cymbidium goeringii and Cymbidium faberi mostly grow in temperate mountain forests; in temperate regions, the summer temperature can reach as high as about 38 degrees, but in shaded mountain forests the daytime temperature does not exceed 30 degrees, and at night it is around 18 degrees. In winter, under short-term snow cover, the surface temperature still exceeds 5 degrees, and flowering is not affected. Indoors they can also overwinter at around 0 degrees. The suitable growth temperature for Cymbidium goeringii var. longibracteatum is 18-28°C, not exceeding 35°C in summer, not lower than minus 2°C in winter, and the reproductive growth temperature is 8-18°C. The temperature requirements for Cymbidium tortisepalum are generally not lower than minus 12°C in winter; during the reproductive period in spring and autumn, the temperature should not be lower than 12°C; during the summer growing period, the temperature is mostly suitable between 15°C-32°C, with above 35°C being the critical line for growth, and beyond this limit growth stops again.

The driving force of orchid life -- light

"All things grow relying on the sun." This sentence highly summarizes the enormous role of light in the growth and development and generational continuation of living things, especially plants. The orchid itself relies on the photosynthesis of green leaves to obtain energy to maintain and continue life and to carry on the line, and sunlight is the driving force of orchid life. But for orchids, which require half-shade and half-sun habits, excessively strong light is also harmful to orchid growth, and light suitable for orchids must be regulated and controlled according to the temperature and humidity of different seasons and the growth habits formed under the ecological environments of various orchids, so as to satisfy and benefit the survival and growth of orchids. Below, regarding the close relationship between light and orchids, I will discuss a somewhat immature view and explore it somewhat with fellow orchid enthusiasts, which may be of some use for growing orchids well:

Below we explore from five aspects:

One, the relationship between light and orchid growth.

Two, the effects of light on orchid leaves, buds and flowers:

Three, the role of light in orchid fertilization and sterilization.

Four, the light intensity for orchids.

Five, artificial regulation of light.

One, the relationship between light and orchid growth.

Suitable light can promote normal orchid growth: orchid growth relies on the photosynthesis of green leaves to obtain energy to maintain and continue life, and light's effect on the photosynthesis of Cymbidium plants is accomplished through light quantity and light quality.

① "Light quantity." That is, the intensity of light. Plant photosynthesis changes with changes in light intensity, and photosynthetic intensity is in direct proportion to light intensity. That is, when light intensity doubles or halves, photosynthetic intensity also doubles or halves. Light, through the chemical action of chlorophyll in orchid leaves, absorbs carbon dioxide and releases oxygen to increase the nutrients needed by the orchid body. The corms and roots carry out digestion and decomposition at night, converting carbon dioxide into sugar, and then into various needed proteins, which are transported to all parts of the plant by the flow and pressure of water and air, so that the potted orchid can grow shoots and bloom. Photosynthesis has a heat limit and a cold limit, that is, the maximum temperature and the minimum temperature, also called the critical points of photosynthesis. Too much and too strong sunshine, exceeding the critical point, will cause leaves to become dwarfed and yellowed, and even to age prematurely and stop growing, gradually declining and dying; conversely, if light is insufficient, although the plant still grows, the nutrients produced are not enough, which is likewise unfavorable to the healthy growth of orchids. Therefore, the levels of the plant's light compensation point and light saturation point directly affect the accumulation of organic matter and healthy growth of orchids. To make crops grow well, attention should be paid to lowering the light compensation point and raising the light saturation point. The usual measures are: sun plants should be reasonably densely planted, controlling population development and ensuring the plants have enough light; if natural light is insufficient, increase artificial light; shade plants should be moderately shaded on the premise of satisfying their photosynthetic intensity as much as possible. Letting orchids have relatively abundant light of sufficient duration is beneficial.

② "Light quality." The regulation of light should consider not only light quantity but also light quality. The intensity of plant photosynthesis differs according to light quality. Sunlight contains seven kinds of visible light as well as invisible light such as ultraviolet. But orchid leaves respond only to the red, orange, yellow and blue-violet series of light. The different colors of sunlight produce differences in the intensity of plant photosynthesis; red light and blue-violet light are more efficient, while yellow-green light is lower. Not only does the intensity of photosynthesis differ, but the photosynthetic products are also not entirely the same; for example, when plants grow under blue-violet light, the amount of protein and fat in their photosynthetic products increases, while under red light more carbohydrates are formed. Infrared light irradiation is beneficial to plant cell division, showing as thickening in plants; far-infrared light irradiation is beneficial to plant cell elongation, showing as growing taller in plants; ultraviolet light irradiation is beneficial to shortening the nodes of orchids, showing as dwarfing in plants. Therefore, supplemental lighting for orchids should set different light qualities according to the specific growth conditions and requirements of the orchid seedlings (ordinary incandescent lamps have less blue-violet light and more infrared light than the sun; fluorescent lamps have more blue-violet and green light and less red light; the visible part of xenon lamps is close to sunlight, but their ultraviolet and infrared light are greater than the sun's). Orchid cultivation generally uses mostly red light and blue-violet light. Experts suggest that supplemental lighting for Chinese orchid cultivation should use more red light. Of course, if conditions permit, choosing plant lights specially designed for orchid supplemental lighting is even better.

In short, one should, according to the type of photosynthetic products needed as described above, consider comprehensively, make up for deficiencies by drawing on strengths, and select suitable light sources to promote the normal growth of orchids.

Two, the effects of light on orchid leaves, buds and flowers:

1. The effect of light on orchid leaves.

① Orchid leaves under different light: orchids have long grown in mountain forests and developed a half-shade, half-sun habit, liking scattered light and not liking direct strong light. When light is too strong, orchid leaves tend to be shorter, thicker and stiffer, with a rough leaf surface, and the leaf color turns pale green. If suddenly exposed to strong light, the leaf color quickly turns yellow, the leaf surface becomes rough, and the leaves may even scorch. With moderate light, the leaves are green with a fine texture and luster, and grow robustly. With too weak light, the leaf color is emerald green, and the leaf texture is thin and long without luster. In short, the stronger the light, the more yellow the leaf color; the weaker the light, the deeper green the leaf color. Too strong or too weak will both affect the perfect growth of the orchid.

② Changes in light can promote the manifestation of leaf art. Plants with the possibility of variable art can receive a longer light duration, and for line-art orchids the sunlight from 6 to 9 in the morning is best. Someone did an experiment with this method: before 9 o'clock in summer and before 10 o'clock in winter, expose the orchid pot to sunlight, insert a thermometer into the pot, and when it has been sunned to 30°C move it into the shade. When it drops to 25°C, move it out again into the sunlight. Repeat this over a long period. One shade and one sun, one cold and one hot, is beneficial for the appearance of variable factors within the leaves; over the years, variegated leaves may appear. But this must be premised on the existence of recessive factors for leaf art within the orchid leaves; the change in sunlight merely promotes their manifestation, and there is no inevitable connection. White-spotted cells are the decisive factor and play the decisive role in changes in orchid line art.

2. The effect of light on sprouting. Light can increase the sprouting rate of orchids. Orchid sprouting cannot rely solely on water and fertilizer management; appropriately increasing light is very crucial. The sprouting rate of those receiving strong sunlight is generally high; strengthening light can not only increase the sprouting rate but also make new shoots stronger.

① Shallow planting of orchids produces more sprouts. Orchid growers generally believe that "deep planting is not as good as shallow planting" for orchids. This is because when orchids are planted deep, the corms are buried deep and receive little light; under the same fertilizer, water and management conditions, deeply buried corms are small and sprout less in spring. When planted shallowly (with half the corm exposed above the soil), the corms are large and sprout more in spring. This is closely related to the spectrum and the length of light duration. It also demonstrates the principle that light can increase the sprouting rate of orchids.

② Light can promote flower bud differentiation and achieve the goal of more flowering. This is because light is the source of nutrients for flower bud differentiation and growth. The strength of light has a direct impact on the number of leaf buds and flower buds, the time they emerge from the soil and their growth condition. Orchids with sufficient light produce more nutrients through photosynthesis, have more flower bud differentiation, bloom more, have deeper flower color, and have large, good flower shapes. Conversely, with too weak light, although the orchid plant grows luxuriantly, the nutrients produced are not enough, and it grows many leaf buds and few flower buds. Even if it flowers, the flower color is on the pale side, the flower shape is also poorer, and the growth condition is poor. Therefore, appropriately increasing light for a period before flower bud formation can promote flower bud differentiation and achieve the goal of more flowering.

3. The effect of light on flowering:

① The strength of light and changes in flower color. Sunlight is the fundamental source of color for all things in the world. The seven colors of the rainbow can change in countless ways, and the original colors of orchids are composed of ever-changing original light. The violet light and ultraviolet light in light are the main light energy forming orchid pigments. Therefore, sunlight has a direct effect on the colored flowers of orchids. When light is strong the flower color is deeper and more vivid; when light is excessively weak the flower color is extremely pale. For example, to make the flower color of the red-flower series beautiful, sunlight can be slightly strengthened; to make the blue series produce beautiful flowers, sunlight should be reduced. Colored flowers should be appropriately shaded during the flowering season, because under sunlight red light and green light are not absorbed, while petal-type flowers should be on the more sunny side to thicken the petals. In cultivating colored flowers, paying attention to and controlling light well during cultivation can make the flower color more beautiful. Green and white flowers should have reduced light; red, yellow, pink and purple flowers need increased light. For example, if Cymbidium goeringii blooms in shade, the flower quality and flower color are better than when it blooms in sun (except for colored flowers), and the flower stalk is also longer. For Cymbidium faberi and Cymbidium ensifolium, stronger light is beneficial to flowering, and the flowers are large with good color and fragrance. Therefore, controlling and regulating reasonable light is a maintenance technique that must be mastered to fully express the best flower color.

② The effect of light on orchid opening.

For orchids with flower buds, early or delayed flowering can be achieved by regulating the length of the light period. Appropriately extend the light and increase the temperature. For example, using a 100-watt bulb or infrared lamp in a small room to raise the room temperature by 3°C-5°C can promote earlier flowering. Similarly, orchids with flower buds placed in a location with weak light and low temperature can have their flowering delayed. For orchids that have already formed flower buds, appropriately extending sunlight exposure and raising the temperature, or using a 100-watt bulb or infrared lamp in a small room to raise the room temperature by 3°C-5°C, can accelerate the flowering period and bring flowering earlier. Conversely, reducing light under a low-temperature environment can delay the flowering period, because raising or lowering the temperature can accelerate or slow down the physiological activities within the plant. Using this biological characteristic, some people have experimented and found that extending the light period to 14-16 hours can promote earlier flowering in medium-sized plants and small seedlings; but for mature orchid plants, a light period of no more than 8 hours is sufficient to promote flowering. Appropriately adjusting light intensity can make orchids bloom at the right time, especially species that bloom in spring. Generally, flower buds have already formed by July-September of the previous year, and after they pass through the winter dormancy stage, appropriately increasing light and raising temperature can bring flowering earlier, in time for the Spring Festival holiday. Conversely, appropriately reducing light and lowering temperature can also delay flowering, in time for orchid exhibitions. In short, regulating light intensity can make orchids bloom at the right time.

III. The role of light in fertilizing and sterilizing orchids.

1. The relationship between light and fertilization. Generally, how to shade and supplement light for various orchids in different seasons and at each growth stage so that they receive appropriate light intensity is a concern for everyone. However, in the process of orchid cultivation, how to correctly handle the relationship between fertilization and light may not necessarily receive attention. In fact, this is equally important for the vegetative growth of orchids. The strength or weakness of light will lead to the strength or weakness of assimilation. If the light is too weak, the assimilation of the leaves will also be insufficient. This leads to poor digestion of nitrogen fertilizer during the day, less accumulation of carbohydrates and starch, and therefore less decrease at night. Over time, the leaves will become very long while the roots remain very short. If the light is too strong, the assimilation of the leaves will also be too strong. The respiration of the orchid plant increases, consuming excessive nitrogen fertilizer, causing the leaves to become short, small and yellowed. At the same time, abundant carbohydrates and amino acids cause excessive elongation of the pseudobulbs and roots. There may be multiple reasons for these two adverse growth conditions; light is not the only factor (such as long-term dryness of the orchid pot, excessive stem fertilizer, high-carbon growth, small day-night temperature difference, nitrogen deficiency, etc., can also cause these problems). Failure to correctly handle the relationship between fertilization and light is also one of the important reasons, and must be given attention. The maintenance measures for such situations are: when orchids show a "long leaves, short roots" condition, light intensity must be gradually strengthened, organic nitrogen continuously supplied, and water supply reduced. After new roots grow out, they will slowly return to normal. When orchids show a "small leaves, strong roots" condition, light should be reduced and sufficient inorganic nitrogen continuously supplied. This can both lower the carbohydrate content and promote protein synthesis, and the new growth will return to normal.

Practice has proven that only under conditions of sufficient light can orchids absorb nutrients, so when fertilizing orchids there must be moderate sunlight. The best time to fertilize is on a morning with good weather. When applying chemical fertilizers, the light intensity should be relatively higher; when applying organic fertilizers, it should be relatively lower.

2. Sunlight is a good weapon for sterilizing orchids and preventing disease. Light not only increases temperature; the ultraviolet rays in the spectrum can kill and prevent the growth of fungi, pathogens and viruses. Pathogenic bacteria generally find it very difficult to survive under intense sun exposure. Therefore, through sun exposure, pots and planting media can be sterilized and disinfected. However, for the sterilization and disinfection of orchid plants, the use of sunlight must be timed. For example, sun the orchids in winter, letting the entire plant bathe in ample sunlight; in summer, avoid the intense sun exposure at noon and in the west-facing afternoon sun. Light can also close the stomata of orchid leaves, blocking pathogenic fungi that easily invade through the stomata. We have found that orchid plants in good light have strong disease resistance, while orchid plants in poor light, because their stomata are often in an open state, are prone to infection by invading pathogens. Orchid plants with insufficient light are prone to pests and diseases. Using sunlight for sterilization and disinfection has always been advocated by orchid growers. The photosynthesis of orchids, like other biochemical processes, cannot exist in isolation, and is also constrained and influenced by external environmental conditions. These external factors are: light intensity, carbon dioxide and oxygen concentrations, wind speed, temperature, water supply, inorganic nutrients, and pollutants in the atmosphere and soil, etc. In addition, photosynthesis is also affected by internal factors of the plant itself, such as chlorophyll content, degree of stomatal opening, and the physiological state and structure of the leaves themselves. By improving these internal and external factors, the goal of increasing the plant's photosynthetic efficiency can be achieved, promoting healthy development, growth and flowering of orchids. In summary, according to the growth habits of orchids, giving appropriate light can improve fertilization efficiency, enhance disease resistance, and benefit the healthy growth of orchid plants. For this reason, for orchid plants that are weak, do not bloom, and are prone to pests and diseases, light must be strengthened.

IV. Light intensity for orchids.

1. Orchids grow in mountain forest areas, and their ecological environment has cultivated a need for semi-shade, semi-sun light conditions. There is a folk flower saying: "Shade for camellias, sun for peonies, half shade half sun for Cymbidium ensifolium." This shows that orchids have a semi-shade, semi-sun light habit, and the growth of all types of orchids cannot be separated from light. This is also a "common characteristic" of orchid plants.

2. The light requirements of various orchids are not exactly the same. Due to differences in ecological environments, various orchids differ in their light requirements, ranging from strong to weak. Generally speaking, Cymbidium faberi and Cymbidium ensifolium need more light for growth and can be shaded less. However, in the vigorous growing summer and early autumn, strong direct light will still scorch some leaves, causing the leaves to turn brown, and even causing the leaves to become scorched yellow and withered. At this time, shading is necessary, blocking 70%-80% of sunlight. Cymbidium kanran and Cymbidium sinense relatively need less light, and in summer should be shaded from 80%-85% of sunlight. For newly potted plants, diseased and weak seedlings, old plants, particularly delicate plants, and plants that have not been hardened and have long been in semi-shade semi-sun conditions, shading must be provided during the growing period. For variegated-leaf orchids, striped orchids, crystal orchids, and transparent-bodied types, they cannot receive relatively strong direct light. Shading must be provided when sunlight is strong. The amount of shading is also a rough estimate, because different varieties under the same species do not have absolutely identical light requirements. For example, variegated orchids, colored-flower orchids, and strong versus weak plants of the same species all differ in their light requirements. This is the "individuality" of orchid plants, and growers need to observe carefully to correctly grasp the appropriate light level for each type of orchid.

3. Orchids can be roughly divided into three categories: sun-loving, semi-shade, and shade types. As well as long-day and short-day types. Long-day orchids bloom as the days gradually lengthen and the nights gradually shorten; such as Cymbidium ensifolium and summer Cymbidium kanran that bloom in late spring and summer. Short-day orchids are the opposite, blooming as the days gradually shorten and the nights gradually lengthen, such as Cymbidium goeringii, Cymbidium tortisepalum, Cymbidium faberi, and Cymbidium sinense that bloom in late autumn and winter.

4. Reference values for optimal light intensity for various orchids (unit: LUX)

Orchid species Light range Optimal light intensity Variegated orchid light intensity

Cymbidium ensifolium 10000-14000 **** 10000

Cymbidium faberi 9000-13000 11000 9000

Cymbidium goeringii 8000-**** 10000 8000

Cymbidium tortisepalum 8000-**** 10000 8000

Cymbidium lianpan 8000-**** 10000 8000

Cymbidium kanran 8000-**** 10000 8000

Cymbidium sinense 4000-**** 5000 4000

"Fairburn and Prill point out: no one can propose the best light quality and light quantity for orchid growth and development, because this involves complex factors, including light, temperature, different times, carbon dioxide concentration, day length, nutritional conditions, humidity, and the day-night temperature difference, etc." -- Excerpted from Wu Yingxiang's "Chinese Orchids." Therefore, the light intensity values above are only reference values.

5. The light intensity for orchids changes with the seasons: Orchids should receive more sunlight in winter and spring, and basically can go without shading. In summer and autumn, they should get more sun before 8-9 in the morning, and must avoid the west-facing afternoon sun, otherwise orchids are prone to disease. Sunlight and temperature have a great influence on orchid reproduction. If there is no sunlight for a long time in winter and the temperature is relatively low, it will affect the formation of winter buds, leading to fewer and poorer-quality seedlings in spring, affecting the rate of plant increase for the entire year.

6. Orchids prefer light in a cool environment. Generally, shading begins when spring turns to summer and ends only after late autumn. In summer, shade 40-50%; in late autumn, winter and spring, they should receive full light. Generally speaking: at 20-25°C with direct sunlight, the chlorophyll in orchid leaves reacts quickly with light, and the plants grow vigorously. Above 30°C, the chlorophyll in the leaves automatically decreases, the leaf color fades, and a gray visible film gradually forms to reflect sunlight and prevent scorching. This condition can only be maintained for a relatively short time; if it lasts too long, it starts from the leaf tips first, and the entire plant gradually dies, especially older plants which first turn yellow and then become scorched and withered. Therefore, the length of time orchids receive light changes with high or low temperatures, in an inverse relationship.

7. Orchids prefer morning sunlight. When the morning sun first rises, the sunlight angle is low, and the orchid receives light over a large area. Also, because the morning sunlight is blocked by morning mist, the light is relatively soft, and direct exposure will not scorch orchid leaves. After orchids accumulate nutrients at night, their photosynthetic capacity is strongest in the morning.

V. Artificial regulation of light.

Light that is too strong or too weak is harmful to orchid growth, and orchid lighting varies greatly with season, weather, region, environment, etc. If light is too strong as a result, artificial shading must be used, adjusting the shade density to reduce the light for orchids. If light is insufficient as a result and affects the healthy growth of orchids, artificial lighting must also be used to appropriately supplement light for orchids, giving them relatively ample light of sufficient duration. In short, to give orchids appropriate light, it must be regulated artificially.

1. Basis for regulating orchid lighting:

① Regulate the appropriate light for each type of orchid according to differences in light requirements among species. Different orchid varieties will also differ in photosynthesis and optimal temperature. For example, different orchid species and variegation types will differ at different times and in different regions. On scorching days of midsummer and golden autumn, regarding shading requirements, Cymbidium ensifolium needs a shade density of 60%-70%; Cymbidium goeringii and Cymbidium faberi require 70%-80% shading in summer, while Cymbidium sinense needs about 80-85%. Ordinary striped variegated orchids can be at about 80%; high-grade striped variegated orchids, crystal variegated orchids, and patterned variegated orchids should be at about 90%. Flower-type orchids and ordinary striped variegated orchids can receive full light before 9 AM and after 4 PM on sunny days; high-grade striped variegated orchids, crystal variegated orchids and patterned variegated orchids should be half-shaded. In high-temperature "furnace" regions, the shading density should be increased by more than 5% accordingly. In winter and spring, appropriately increasing light by 20% is more beneficial for orchid growth.

② Adjust the shade density according to the light duration and light intensity of different seasons. From late spring to summer and autumn, shade 40%-50%; in winter and early spring, 10%-20% light. Insufficient light will make orchid leaves soft with a deep color, and cause the leaves at the rhizome area to bend downward or outward. Especially during the leaf-pulling period, it makes the leaves grow excessively fast. Conversely, too much light will make the leaves turn yellow or the chlorophyll be destroyed, causing cell death, and excessive light makes the leaves shorter and thicker and open prematurely or bend outward. Therefore, except in early winter and midsummer, move the orchids outdoors in the morning until 9-10 o'clock, so they can get sufficient light. As the angle at which sunlight strikes the earth shifts, the light duration, light intensity, etc. will all change. In the short and weak-light winter and spring seasons, except that high-grade striped variegated orchids, crystal variegated orchids and patterned variegated orchids need 60%-70% shading, all other orchids can receive full light, or be half-shaded daily from 10-14 o'clock on sunny days. In the long and strong-light summer and autumn seasons, the shading time and density for orchids must also be adjusted accordingly.

③ According to weather changes. With ever-changing weather such as sunny, partly cloudy, cloudy, overcast, and rainy or snowy days, light also changes frequently and correspondingly. Therefore, the shading degree must be appropriately adjusted as the weather changes and light strength varies. In particular, high-grade striped variegated orchids, crystal variegated orchids and patterned variegated orchids cannot tolerate strong light; if the shading degree is not adjusted in time, it often leads to sunburn damage. In addition, if a fixed shading density is maintained regardless of light strength, the sprouting rate and flowering rate of orchid plants will naturally be worse than with timely adjustment.

④ According to the daily changes in sunlight, such as clear turning to overcast, overcast turning to clear, clear turning to rain, and clearing after rain, the morning and evening sunlight can be allowed to shine freely, but the noon intense sun must be blocked and regulated, and on overcast days the shade density should be reduced. It is worth noting that after a summer rainstorm, or when it first clears after a long period of rain, orchid pots must absolutely not be exposed to the scorching sun. The experience of predecessors: "If exposed to the sun right after rain, the water in the pot is hot, which will scald the leaves and damage the roots."

⑤ Regulate specifically according to differences in climate, light intensity, etc. in different regions. China is vast, and climate cold and heat and light intensity vary greatly, but the standards for strong, weak and appropriate light for orchid growth are still unified and can be specifically regulated according to the local climate.

⑥ Regulate according to temperature. The photosynthesis of orchids is closely related to temperature. Generally speaking, Chinese orchids carry out normal photosynthesis at 5-36°C, with the optimal temperature being 18-28°C. At temperatures as low as 0°C and as high as 40°C, which are the limits, orchid photosynthesis is inhibited. Starting from the low limit, photosynthesis strengthens as temperature rises. Beyond the optimal point, photosynthesis declines; above 36°C photosynthesis is very weak, and when reaching the 40°C limit, photosynthesis stops. When the temperature is high, use shading to cool down; when the temperature is low, use heating equipment to raise the temperature, thereby achieving a relatively suitable temperature, promoting orchid photosynthesis, and ensuring healthy and rapid growth of orchids.

⑦ According to the phototropism of orchids. Orchids have phototropism, so the direction of the orchid pot should be rotated and adjusted at intervals, to prevent the plant leaves from leaning to one side. In particular, the side with new growth should face the direction of ample light during the budding period, to facilitate sprouting and healthy growth of the buds. If for special modeling or compositional needs, to express a specific poetic and artistic conception, the position of the light source can also be used to strengthen the tendency of flowers and leaves, achieving the beauty of dynamic balance, which can satisfy appreciation needs.

⑧ Regulate according to the growth condition of the orchid. Generally speaking, if the leaf color is light green, and the orchid leaves are thin and weak with excessive elongation, then the light is too strong. If they appear yellow-white or even scorched yellow and withered, it indicates that the light has exceeded the orchid plant's tolerance. Conversely, if the color is dark green or deep green without luster, it indicates that the light is too weak. Regulate shading well according to the growth condition of the orchid. In addition, if the stems and leaves are relatively dense and soft, with many leaf buds and few flower buds, then light is insufficient; conversely, if the stems and leaves are sparse and firm, with few leaf buds and many flower buds, then light is too strong. Neither is normal and both need timely adjustment.

⑨ Regulate light according to the growth period of the orchid. During the growing period, the light supplementation time should be longer; during the dormant period, less.

⑩ According to professional testing. (Excerpt)

⑴ The light intensity for well-growing orchids is 4000-5000 Lux (lux, the unit of light intensity), at which their sprouting rate, flowering rate, leaves and leaf color are all excellent.

⑵ From the practice of professional testing, it has been found that orchids have a saturation point for light requirements. After light reaches the saturation point, even better sunlight is harmful rather than beneficial to orchids.

⑶ Plants most easily absorb red and blue light, and a balanced combination of red and blue light is especially important for photosynthesis. Experiments have proven that red light can promote orchid growth, while blue light is indispensable for thickening leaves, accelerating plant development, and regulating stomatal opening. Green light should also not be ignored; it can promote oxygen production, thereby helping orchids better accumulate nutrients.

⑷ A certain intensity of long-wave ultraviolet light is also indispensable; it helps form anthocyanins and inhibit the elongation of branches and leaves.

2. Methods for regulating orchid lighting:

First, shading. In nature, orchids mostly grow in cool, shaded mountain forest environments with scattered sunlight, and semi-shade and shade types account for more than four-fifths of all orchid plants. Therefore, when light is too strong, shading must be used to reduce light.

(i) Plant shading. Imitating the natural environment, using plants for shading is one of the more ideal methods. The method is: on the orchid cultivation site, set up bamboo frames, wooden frames or reinforced concrete frames, and let grapevines, honeysuckle, morning glory, Chinese trumpet creeper, cypress vine and other climbing plants spread over them, which both provides shade and is attractive. Deciduous climbing plants provide shade in summer and let light through in winter, which is a kind of natural regulation. Trees can also be planted around the orchid garden, selecting evergreen trees, deciduous trees, and bamboos of different heights to plant in combination, to regulate light intensity.

(ii) Shade net shading. The shade shed can be built with bamboo, wood, angle steel, etc., covered with bamboo blinds, plastic film, shade nets, etc. On top, set up a double layer of shade net with 50%-70% shading rate; the upper layer is relatively fixed and only rolled up in winter, while the lower layer can be deployed or retracted. Use double layers in midsummer, single layer in spring and autumn; use double layers at noon on sunny days in summer and autumn, and single layer on cloudy and rainy days. In winter, it depends on the situation: on sunny days deploy the lower layer, on cloudy days roll up the lower layer. In addition, before orchid flower buds are about to open, they must have moderate scattered sunlight, otherwise the flower color will be dull and not showy. It is best to install the shade net in a movable style, so that the shade density can be increased or decreased as needed. The shade net should as much as possible not be placed tightly against the plastic film or glass on the top of the shed, and there should be a gap of about 30 cm between net layers. The shade net should be set outside the plastic film or glass, so that the shading effect is good. If set inside the shed, its shading effect is greatly reduced. When growing orchids on a balcony, during midday when direct sunlight is strong, and when walls have reflected light and radiant heat, and ventilation is also poorer than in a courtyard or orchid nursery, so in high-temperature seasons, a 50% shade net should be hung outside the security grille for 3-4 hours around midday to prevent scorching the orchid plants. When the sunlight slants and the temperature has also dropped, it should be rolled up in time to facilitate ventilation. Orchid shading requires a certain regularity. Generally speaking: large-leaf types need more than small-leaf types, low-altitude types need more than high-altitude types. More shading is needed in summer, less in winter; more shading at noon, less in the morning and evening; more shading at high temperatures, less when cool, etc.

Second, "light supplementation." Regulating light in orchid-growing sites is not just about shading. When natural light is insufficient, artificial lighting also needs to be added to appropriately supplement light for orchids, especially for indoor orchid growing and after the onset of winter when the light duration is short, which has a certain impact on orchid growth. Only by supplementing light to meet the light requirements of orchids can orchid plants develop soundly, with sturdy stems, and grow and bloom.

(i) Basis for light supplementation. How to supplement light appropriately, and what kind of light to supplement? There must be a scientific basis. Sunlight is a collection of continuous bands of light from red to violet, and artificial simulation of the plant growth environment should also start from this. In addition to considering the light quality and light intensity necessary for orchid growth, artificial light supplementation also needs to consider the physiological radiation characteristics of the light source. (Light waves that match the characteristic curve of plant chlorophyll synthesis are called physiological radiation light sources, i.e., photosynthetic light waves.) Under different light qualities, not only does the intensity of photosynthesis differ, but the photosynthetic products are also not completely the same. For example: plants absorb red light most strongly, followed by blue light. When plants grow under blue-violet light, the amount of protein and fat in their photosynthetic products increases, which is effective for thickening stems and leaves, accelerating plant development, and regulating stomatal opening. Under red light, more carbohydrates are formed, which can promote orchid growth. Violet light and ultraviolet light mainly form anthocyanins and inhibit the elongation of branches and leaves (ultraviolet light must not be too strong, as it will scorch orchid leaves). Green light should also not be ignored; it can promote oxygen production, thereby helping orchids better accumulate nutrients. In addition, a certain intensity of long-wave ultraviolet light is also indispensable; it helps form anthocyanins and inhibit the elongation of branches and leaves. Light supplementation must be based on the effects of the above spectra and the growth condition of the orchids to select a suitable light source.

(ii) Light source selection. Because light quality has a clear influence on the composition of photosynthetic products, people should select suitable light sources according to the type of photosynthetic products needed. Ordinary incandescent lamps have less blue-violet light and more infrared light than the sun; fluorescent lamps have more blue-violet and green light and less red light. Generally speaking, orchid cultivation can use a mixed light of red, blue and white tubes to supplement insufficient light. A complete combination of red and blue spectra can enable orchids to achieve optimal growth. Philips' tri-phosphor 6400K fluorescent lamp can basically meet the growth requirements of orchids, and is inexpensive. Of course, if conditions permit, it is best to choose plant lights specially designed for orchid light supplementation; they are a bit more expensive, but the effect is better. Using LED lighting, the plant growth rate and photosynthetic rate both increase by more than 20%. LED lamps have stronger durability than ordinary lamps and save electricity, reducing operating costs. When selecting a light source, one should consider not only light quality and light quantity, but also low power consumption, economy, durability and ease of use.

(iii) Light supplementation time. After installing artificial lighting equipment in the orchid room, the light supplementation time should be determined according to the actual light conditions of the orchid-growing site, the seasonal changes in light, weather changes, and the growth period of the orchids. According to the different growth periods of orchids and the orchid-growing environment, the light supplementation time also differs. Indoor orchid growing with weak light but able to receive scattered sunlight should have no less than 5 hours of light supplementation; balconies should have no less than 4 hours of artificial light supplementation; basements and indoor spaces without sunlight should have no less than 10 hours of artificial light supplementation. During the orchid growing period, the light supplementation time should be longer; during the dormant period, it should be less. On cloudy, rainy and foggy days, there should be no less than about 10 hours of artificial light supplementation. Light supplementation time involves many factors and needs to be tested in practice to arrive at a more correct light supplementation time.

(iv) Light distance. Light intensity is inversely proportional to the distance from the light source to the leaf surface, that is, the closer the distance, the stronger the light intensity. Therefore, the height distance of the light tube can be adjusted to regulate light intensity, to suit the appropriate light requirements of different orchid species. How to choose the light distance: the installation distance of the supplementary light should be set according to the power of the lamp and the height of the orchids. The closer the lamp is to the orchids, the higher the light utilization, but care should be taken to avoid the lamp being too close to the orchids, which causes excessive temperature and harm to the orchids. Fluorescent lamps and special plant light sources (40W) should be at a distance of 20-40 cm; incandescent lamps (100W) should be installed at a certain height from the plants, because the large amount of infrared radiation from incandescent lamps converts into heat energy, so 70 cm or more is preferable; high-pressure sodium lamps (120W-400W) should maintain a vertical distance of 1 m-1.5 m from the plants, which is more suitable. For LED supplementary light sources, because LED produces very little heat, they can illuminate at close range, and 10 cm is preferable.

(v) Light direction. To ensure the light supplementation intensity for orchids, the lamps should as much as possible be arranged directly above the orchids. Benefits: First, due to the phototropism of plants, with more overhead light, the orchid leaves will have stronger uprightness, which meets the aesthetic requirements of orchid lovers. Second, if the angle of the light is consistent with the growth angle of the plant stems and leaves, the light intensity received per unit area is higher, which helps improve light energy utilization efficiency.

(vi) Precautions for light supplementation.

① It is best not to supplement light at night, because orchid growth requires a certain period of darkness to regulate the respiratory function within the orchid plant and to carry out the transformation and synthesis of dry matter within the plant.

② Pay attention to ventilation. Most supplementary lights generate heat energy, especially in summer, which will raise the temperature of the orchid room or orchid shed and cause orchid diseases. Ventilation can reduce heat.

③ Comprehensive configuration of light sources. To obtain better light supplementation effects, light fixtures of different light sources need to be comprehensively configured, such as a combined configuration of fluorescent lamps and incandescent lamps, or a combination of low-pressure sodium lamps and incandescent lamps, to meet the orchid's needs for various spectra.

④ Pay attention to the installation safety of supplementary lighting fixtures to prevent accidents.

The above briefly describes the role of artificial light supplementation for orchids and some specific issues. In short, by appropriately supplementing light for orchids and ensuring they have relatively ample light, not only can the cold resistance of orchids during overwintering be improved, but the vigorous growth and abundant flowering of orchids in the coming year can also be ensured.

Third, "hardening." Orchids have relatively strong adaptability to light, which is also related to the number of generations of light intensity received. They will gradually change and adapt. For orchids that have always been shade-grown, if the plant's light conditions are artificially changed, after a period of time, the structure and function of their chloroplasts will undergo a certain degree of change to adapt to the new light conditions. For example, under weaker light conditions, the leaf structure and function of the plant will develop in a shade-tolerant direction, enabling them to maintain relatively high photosynthetic efficiency under weaker light; conversely, under stronger light conditions, plants can also adapt to a certain extent, effectively using ample sunlight for photosynthesis. The folk term "hardening" roughly means this -- letting orchids adapt to different environments -- including light, temperature, etc. Through "hardening," plants can be made stronger generation by generation.

Fourth, display. In the display of potted orchids, according to the habits of each type of orchid, those with high light requirements should be displayed in places that receive light most often. Those with low light requirements should be displayed in positions with less light. In addition, orchids have phototropism, so it is best to adjust the pot direction once or twice a month, to prevent the plant leaves from leaning to one side. In particular, the side with new growth should face the direction of ample light during the budding period, to facilitate sprouting and healthy growth of the buds.

In summary, light plays a crucial role in the growth, development, flowering and reproduction of orchid plants. Although orchids prefer shade, if all things in heaven and earth had no sunlight, they could not carry out photosynthesis to produce nutrients. And thus could not survive. Therefore, light is the driving force of life for orchids. Photosynthesis is also a rather complex issue. The photosynthesis of orchids, like other biochemical processes, cannot exist in isolation, and is also constrained and influenced by external environmental conditions. These external factors are: light intensity, carbon dioxide and oxygen concentrations, wind speed, temperature, water supply, inorganic nutrients, and pollutants in the atmosphere and soil, etc. At the same time, light is also affected by internal factors of the plant itself: for example, different orchid plants have certain differences in light duration, intensity and requirements. Another example is the influence of chlorophyll content, degree of stomatal opening, and the physiological state and structure of the leaves themselves. Only by improving these internal and external factors can the goal of increasing the plant's photosynthetic efficiency be achieved, promoting healthy development, growth and flowering of orchids.