Which orchid species are suitable for growing at home
According to the different flowering seasons, Chinese orchids can be divided into: 1. Spring-flowering types (Chunlan, Cymbidium goeringii). The main cultivars include: Songmei, Xishenmei, Longzi, Cuiyipin, Wangzi, Cuigaihe, Yingchundie, Xiaodie, Wentunsu, Yuepeisulü, etc. 2. Summer-flowering types (Xialan). These include Huilan (Cymbidium faberi), Tailan, etc.
Lan, etc. 4. Winter-flowering types. These include Molan (Cymbidium sinense) and Hanlan (Cymbidium kanran), etc.
Orchids suitable for growing at home:
1. Chunlan (Cymbidium goeringii). Chunlan's flower color is not showy, but its fragrance is rich, its flowering period is also long, and it is easy to care for.
2. Huilan (Cymbidium faberi). Huilan's leaves are glossy and bright, its flowers are elegant and strongly fragrant, and its flowering period runs from summer to autumn.
3. Jianlan (Cymbidium ensifolium). Jianlan has strong adaptability, is easy to cultivate, and has long and numerous flower stems, with sword-like upright leaves.
4. Tiger-head orchid types. The plants are robust, the flowers are large and brightly colored, the flowering period is also long, and they are easy to manage.
5. Molan (Cymbidium sinense). Molan's leaves are slender, and its flower stems reach as high as 60 cm, standing upright above the leaves. Its petals have purple-brown stripes and are very beautiful.
How to grow Tillandsia and what to pay attention to
Tillandsia is suitable for potted decoration indoors, and can be placed on balconies, windowsills, desks, etc. It can also be hung in living rooms, tea rooms, and can also be used as an accompanying material for flower arrangements. It has a strong ability to purify the air and is used to beautify the environment, novel and elegant. So what are the growing methods and precautions for Tillandsia? Let's take a look below!
I. Growing methods for Tillandsia
1. Best propagation time: The best propagation time for Tillandsia is in early spring.
2. Best growing soil: Tillandsia is best cultivated in loam soil with good drainage.
3. Humidity requirements for growth: Tillandsia needs a relatively high humidity environment. During the growing period, water should be sprayed on the plant frequently to increase air humidity. If the air humidity is above 90%, it can grow completely on its own without any care.
4. Best growing temperature: The suitable growth temperature for Tillandsia is 15°C to 25°C.
5. Best growing light: Place Tillandsia in a spot with bright light but no direct sunlight.
II. Precautions for growing Tillandsia
1. Fertilizer application: Although Tillandsia can grow without fertilizer, it grows slowly and blooms sparsely. In order to make it grow robustly, spray flower fertilizer once every 20 to 30 days during the growing period, and stop spraying in winter and during the flowering period. Of course, some varieties of Tillandsia do not need fertilizer.
2. Key points for watering:
(1) During the growing period, Tillandsia should be sprayed with water frequently to increase air humidity. The best time to spray is at night or early in the morning before the sun comes out. Do not spray water under the blazing sun. When spraying, spray until the leaf surface is completely moist; do not let water accumulate in the center of the plant, so as to avoid “heart rot”.
(2) During the growing season, keep the potting soil moderately moist for Tillandsia. In hot weather, spray the plant twice a day. When the temperature is low, water less and just keep the potting soil moist.
Pruning essentials: After the flower spike of Tillandsia and similar plants withers, the flower spike needs to be cut off so that new shoots can grow better.
Repotting: As long as there are no major problems during planting, Tillandsia does not need repotting.
Propagation essentials: Home cultivation of Tillandsia can be propagated by the method of separating basal offsets. When the basal offset grows to 8 cm long, detach it and plant it.
Pest and disease control: Tillandsia is easily harmed by red spider mites and scale insects. Control method: spray with 40% dimethoate emulsifiable concentrate at 1500 times dilution to kill them.
III. Tips for growing Tillandsia
1. In hot seasons, Tillandsia should be shaded and watered thoroughly. In winter, it should be placed indoors in a spot with plenty of sunlight, and water should be controlled. The temperature must not be lower than 10°C.
2. Spray the leaves of Tillandsia with liquid fertilizer once every 2 weeks.
3. Keep the potting soil of Tillandsia moderately moist at all times and give it sufficient diffused light.
4. Remove the faded flowers of Tillandsia immediately after they wither.
A complete guide to orchid growing and cultivation techniques
"Three parts planting, seven parts care" - this is the ancient experience in growing orchids. The quality of care determines whether the orchids will flourish and whether they will bloom, so it makes sense that the ancients attached great importance to this. Below is a detailed 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. Orchids are generally 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 moist air. Indoors, there should be plenty of light, preferably facing south. This is beneficial for orchid growth. Orchid pots are best placed on wooden racks or tables, not on the ground.
II. Shading
Most orchids belong to the semi-shade plants, and most species are afraid of direct sunlight, so proper shading is needed. In early to mid-April, orchids can receive more sunlight to promote their growth. After late April, proper shading is needed. Among Xialan and Qiulan, varieties with upright leaves are best placed in a shaded spot on the south side so that they receive a moderate amount of sunlight; for drooping-leaf Qiulan and Chunlan, two hours of light per day is best. From June to September, shade should be provided earlier each day; for example, with reed blinds, use dense blinds or two layers of sparse blinds. After October, when the weather turns cooler and the sunlight is weaker, shading can be delayed, but around noon, attention should still be paid to providing shade.
III. Rain protection
Orchids can be exposed to light rain, but must be protected from plum rain, showers, or continuous rain. During 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 is short in duration and light in amount, more water should be given in the evening to let the heat inside the pot escape; otherwise the orchids will be damaged, or even have root rot and die. If a shower is followed by sunshine, shade should be provided in time to prevent the heat rising from the ground from affecting orchid growth. The rainy season coincides 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 humidity of the potting soil.
IV. Watering
There is a saying in flower-growing lore: "Dry orchids, wet chrysanthemums," and there is some truth to this. Generally speaking, orchids are best kept at eight parts dry and two parts wet. 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 lean appropriately toward dry. In practice, generally note the following: during the growing period (May to the end of June), water appropriately more; during the leaf bud sprouting period (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, dry weather, water appropriately more; in cold, damp 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 and keep the potting soil on the drier side; this will prevent root rot and help produce new leaves. The ancient experience of "not dry in autumn, not wet in winter" is a good summary of how to water Chunlan and Xialan. 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, water after sunset so that the orchid leaves dry before nightfall, or water in the early morning; in winter and spring, water around sunrise. Do not suddenly water with cold water after scorching sun exposure, so as to avoid lowering the soil temperature, affecting root water uptake, and disrupting physiological balance. The amount of water should not be too large, so as 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, so as to avoid causing rot.
The ancients had very good summarized experience on watering orchids. For example, in "Records of Orchid Growing in the Capital" (Dumen Yilan Ji), Yu Zhao proposed different watering methods according to the twenty-four solar terms within a year. The following is an excerpt for reference. But two points need attention: first, "Records of Orchid Growing in the Capital" uses Beijing's climate as the standard; second, the months in the text refer to the lunar calendar, not the Gregorian calendar, so for example "the first month" is actually February in the Gregorian calendar.
1. Lichun (Beginning of Spring) and Yushui (Rain Water): Chunlan has already set flowers, so the soil should not be too dry; moisten it slightly along the edge of the pot. For Qiulan pots, if the soil has not dried to the bottom, do not water.
2. Jingzhe (Awakening of Insects): When the Chunlan pot soil is dry to half the pot (empty above, solid below), it can be moistened, but not too much. Same as above for Qiulan.
3. Chunfen (Spring Equinox): Chunlan has finished flowering and should avoid dampness; when the pot is half dry, it can be moistened.
4. Qingming (Pure Brightness) and Guyu (Grain Rain): Do not let the potting soil become too dry; moisten with water every 5 days.
5. Lixia (Beginning of Summer): Orchids begin to be brought out of the room, and it is suitable to water thoroughly once.
6. Xiaoman (Lesser Fullness): The potting soil should not be too dry or too wet. If spots appear on the leaves, it is too wet; if the tips of new shoots wither, it is too dry. Water one sheng every 4 days (about one dry teacup), so that the lower 2/3 of the potting soil from the bottom up is moist.
7. Mangzhong (Grain in Ear): The climate is dry, so pay even more attention to avoiding too dry or too wet conditions.
8. Xiazhi (Summer Solstice): The potting soil must not be too dry. If there is heavy rain, it can only endure one day. If there are continuous overcast and rainy days, the pot needs to be moved to a ventilated place.
9. Xiaoshu (Minor 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 the potting soil has dried to 2/3 before watering again.
10. Dashu (Major Heat): The potting soil easily dries all the way through, so note that only one heavy rain or one heavy wetting per day is appropriate.
11. Liqiu (Beginning of Autumn): Orchids need moisture at this time. Water 2 sheng every 3 days, and it is also suitable to shelter them from wind.
12. Chushu (End of Heat): Water once every 5 days. Except during continuous misty rain, they can be allowed to receive rain and dew.
13. Bailu (White Dew): Qiulan needs more frequent watering than Chunlan, but after being wet, it must dry out greatly before it can be wetted again.
14. Qiufen (Autumn Equinox): If Qiulan has already produced flowers, water slightly less; if it has not produced flowers, water slightly more.
15. Hanlu (Cold Dew): Qiulan should be watered thoroughly; Chunlan should not be watered thoroughly but only moistened.
16. Shuangjiang (Frost Descent): Orchids should be brought indoors, and the watering time should be changed to midday. After watering, they need to be placed in the midday sun for 1-2 hours.
17. Lidong (Beginning of Winter): Only moistening with water is suitable, about half a sheng every 5 days.
18. Xiaoxue (Minor Snow): The flower room should avoid warmth and should not be too damp. If too damp, it can cause root rot, scarred leaves, and even withering. If the pot soil has not dried to the bottom, only slightly moisten the surface of the soil.
19. Daxue (Major Snow): Qiulan does not need water; Chunlan should be slightly moistened.
20. Dongzhi (Winter Solstice): Neither should be irrigated.
21. Xiaohan (Minor Cold): Watering should be avoided for both.
22. Dahan (Major Cold): Qiulan still does not need water; Chunlan can be slightly moistened with water.
V. Fertilizing
Whether to fertilize orchids should be decided according to the growth conditions of the orchids. Those that grow luxuriantly and are free of disease can be fertilized; those that grow poorly should not be fertilized or should be fertilized only lightly. For orchids newly dug from the mountains, before the new roots have developed, fertilizer must absolutely not be used. They need 1-2 years of cultivation until the new roots are vigorous before fertilizer can be applied; otherwise they are prone to withering and dying.
Generally speaking, in June-July, when the orchid leaf buds have extended to about 1.5 cm, 1-2 applications of thin, fully decomposed liquid fertilizer can be given (chemical fertilizers should not be used), but fertilization is not suitable in high-temperature seasons. In August-September, apply 1-2 more applications of decomposed thin liquid fertilizer. For plain-hearted (suxin) orchid varieties, 1-2 applications of plant ash extract can be given, with very good results. Fertilization is best done in the evening, and the next morning water once with clear water.
A relatively simple way to judge whether orchids need fertilizing is to look at the depth of leaf color. If the leaves are yellow and thin, it is a lack of fertilizer, and topdressing should be applied; if the leaves are dark and the leaf tips are scorched, it is excessive fertilizing, and fertilization 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 fertilization times and dates for orchids: Number of times, Date, Category, First time, Second time, Third time, Fourth time, Notes
Chunlan type: late June, mid-July, mid-August, early September. The fourth application should be especially thin.
Xialan type: late June, mid-July, mid-August, early September. The fourth application should be especially thin.
Qiulan type: early June, late June, late July, mid-August. The fourth application 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 in time to improve ventilation. Some leaves with dried tips should also be cut off. In particular, leaves harmed by pests and diseases need to be removed in time to prevent contagion. When cutting off leaves with viral disease, the scissors used should not then be used to cut healthy leaves, in order to prevent virus transmission. If the same pair of scissors is used, it must be disinfected. For precious orchids, after the flower buds 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, with 1-2 flower buds per pot being appropriate. If there are too many flower buds, it will not only make the current year's flowers bloom poorly, but also consume too much of the mother plant's nutrients and affect the next year's flowering. Generally, orchids do not need flower buds removed. Chunlan flowers bloom for about half a month, after which the flowers need to be cut off; for Xialan 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 it will affect the next year's flowering. If used for hybrid breeding, then they need extra careful cultivation so that the fruit becomes full and ripe.
VII. Cold protection
Qiulan should have cold protection work done early; for example, when the temperature is 2-3°C, it can be moved indoors. Hanlan, growing in the south, needs cold protection even earlier. Chunlan and Xialan have relatively strong cold resistance, but if freezing occurs, they must also be moved indoors in time. A room temperature that can be maintained at 1-2°C is enough for overwintering. If a severe cold wave hits and the room temperature drops below zero, heating should be applied in time; generally it is enough to keep the room from freezing. Indoors, Qiulan should be placed on the south-facing side, and Chunlan and Xialan on the other side. Around noon, windows facing south and southeast should be opened for ventilation (for Qiulan, on cloudy days at 1-2°C, windows must not be opened, to prevent cold wind from blowing in and freezing the leaves). Qiulan likes to be somewhat dry in winter; the potting soil of the other orchids should be kept moist.
VIII. Flower removal
For orchids that grow poorly, with few leaves per clump, or with poor roots, flower removal should be carried out. For better varieties, Chunlan can appropriately have 1-2 flower buds removed; for Xialan, 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 the old leaves are less likely to wither and die. Precious Chunlan flowers should be removed after 3-5 days of blooming, so that the leaf buds grow robustly; for Xialan, when the topmost flower has opened, it can also be cut off at a distance of several cm from the pot surface.
IX. Flood prevention
If the cultivation site is open on all sides and the terrain is relatively high, wind protection work needs to be done in summer when there are strong winds or typhoons passing through, so as to prevent the leaves of Xialan or Hanlan from being broken and damaged.
X. Misting
In dry seasons, 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 surface becomes moist. This can promote good orchid growth and make the leaves glossy.
XII. Pest and disease control
Sterilization treatment should be carried out (exposure under the blazing sun is sufficient) to prevent disease occurrence. Orchids are most prone to southern blight in rainy, high-temperature seasons. It can be prevented by spraying with thiophanate-methyl at 800 times dilution or Bordeaux mixture. If the disease is severe, use thiophanate-methyl at 500-750 times dilution, spraying once every 7-10 days. Among insect pests, scale insects occur most frequently. These insects attach to the base of the leaves. If scale insects are found, they should be removed in time. To avoid scale insect infestation, starting in April, control can be done with "1059" at 2000 times dilution. In order to suppress the occurrence of orchid diseases, in addition to properly controlling the dryness and wetness 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, poorly growing orchids newly dug from the mountains must be planted in clay pots. Doing so makes the potting soil dry easily, which can promote orchid growth and reduce disease occurrence.
How should orchids be grown well?
1. Potting soil requirements: It is best to use neutral to slightly acidic soil containing a large amount of humus, loose and well-drained, 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 grown outdoors and on balconies in spring, summer, and autumn. Choose a place with good ventilation, moist air, and no environmental pollution. Being near a pond or riverside is of course good, but at least there should be tall trees or bamboo groves and shade netting to reduce sunlight exposure and lower the temperature. Orchid pots are best placed on wooden racks (or steel racks); if placed on the ground, bricks should be used underneath. For home balconies, a small galvanized sheet water trough can also be used to store water, with bricks placed on top for growing, to increase humidity.
3. Proper shading: Most orchids belong to semi-shade plants, and most species are afraid of direct sunlight, so proper shading is needed. In early to mid-April, orchids can have the net removed and windows opened to receive more sunlight to promote growth. In May, aside from the midday sun, they can receive 6 hours of light; starting in June, shade all day; after October, aside from midday, they can be fully exposed for cultivation. Remember the saying: "More shade gives good leaves, more sun gives good flowers."
4. Reasonable fertilizing: Orchids are inherently "vegetarian," and fertilizing should be decided according to the selected potting soil and growth conditions. Those that grow luxuriantly and are free of disease can be fertilized; those that grow poorly should not be fertilized or should be fertilized only lightly. Newly planted orchids whose roots have not fully developed can only be fertilized after 1-2 years. Generally, in June-July, when the orchid leaf buds have extended to about 1.5 cm, apply decomposed liquid fertilizer once every three weeks (a thin concentration of 10% is suitable). Chemical fertilizers are taboo. In high-temperature seasons, fertilization is not suitable. In August-September, apply diluted liquid fertilizer once every two to three weeks. Each fertilization of orchids is best done in the evening, and in the morning water with clear water, called "return water."
5. Proper watering: Rainwater and spring water are best for watering orchids; 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 temperature, the degree of dryness and wetness of the potting soil, and the growth conditions of the orchid plant. Water more when there are many leaves, and less when the leaves are fine. In April-May, when new shoots have not yet emerged from the soil, the potting soil should be somewhat dry; if too wet, new shoots easily rot. June-September is the growing period for new orchid shoots, and the amount of water should be increased; on sunny days, water once each morning, and watering under the blazing midday sun must be avoided. In autumn, reduce the amount of water as appropriate; leaf surface misting can be used, and it is better to keep the potting soil moist. In winter, control the amount of water even more, and keep it at "eight parts dry, two parts wet" as appropriate.
6. Evening misting: Orchids originally grow in a moist-air environment, so in dry seasons, in addition to shading, misting must also be done in the evening to increase air humidity and lower the temperature; water can also be poured on the ground (table surface) where the orchid pots are placed. "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 off. Orchids can be exposed to light rain, but must avoid plum rain, heavy rain, or continuous rain, otherwise the heart and leaves easily rot. In rainy seasons, a small amount of plant ash can be sprinkled as appropriate.
8. Pruning and flower removal: During orchid cultivation, withered, yellow, broken leaves, and diseased leaves should be cut off frequently to improve ventilation. For precious orchids, if there are too many flower buds, keep only the strong buds, with 1-2 flower buds per pot being appropriate. Chunlan should be removed half a month after flowering; precious orchids should be removed after 7 days. Then the Chunlan leaf buds grow robustly and bloom better the next year. For Xialan, when the last flower on the inflorescence has been open for one week, cut it off 3 cm from the pot surface.
9. Cold and warmth protection: 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 the position to place them indoors are also different. Hanlan, Qiulan, and Baosuilan grow in the south, and should be brought indoors (or have windows closed and netting drawn) when the temperature is 5°C, and placed in a sunny spot facing south as much as possible. Chunlan and Xialan have strong cold resistance and can be brought indoors only when the temperature reaches 0°C, placed on the northeast side. Around noon on sunny, windless days, windows facing south or southeast should be opened and netting drawn for ventilation. Qiulan, on sunny days at 1-2°C, must not have windows opened. 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 blazing sun is also acceptable) to prevent disease occurrence. 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; for many pots, Bordeaux mixture or thiophanate-methyl at 500-800 times dilution can be used, spraying once every 7-10 days. Among pests, scale insects (commonly known as "orchid lice") occur frequently. During the hatching period, use 1% omethoate and 25% phosmet emulsifiable concentrate at 1000 times dilution, spraying once a week. To treat the symptoms one must treat the root cause: pots should be spaced appropriately, placed at different heights, and ventilation increased, so as to reduce disease occurrence.
(II) Ecological habits of orchid cultivation
Orchids originate in our country. They like warmth and humidity, and the ideal condition is especially warm winters and cool summers. High temperature and dryness must be avoided. In winter, it is best that they do not freeze, and maintaining 3°C to 7°C is most suitable; in summer, 25°C to 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, slightly acidic soil, pH 5 to pH 6.5, and they must avoid water accumulation.
Orchids like shade and require short sunlight duration. In their natural distribution, it is shown that Chunlan requires a tree canopy density of 0.7 to 0.95; Huilan requires 0.5 to 0.8, with a slightly longer light duration than Chunlan; Jianlan, Molan, and Hanlan also require a high canopy density for shade. Cymbidium plants have a dormant habit in their native areas, which depends on the rainy season and the 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 growing period for orchids, when they can continuously bud 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 that grows robustly and has dense pseudobulbs can be divided. After division, each clump must retain at least 5 pseudobulbs connected together. Before division, reduce watering to make the potting soil 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 to occupy 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 Cuiyun grass (Selaginella uncinata) or fine gravel on top, and finally water thoroughly. Place in a shady spot for 10-15 days, keep the soil moist, gradually reduce watering, and carry out normal care.
2. Propagation by sowing: Orchid seeds are extremely fine, and the seed contains only one incompletely developed embryo, with very low germination capacity. 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 3 times with sterile water, then sow them in culture bottles containing culture medium, and then place them in a dark culture room, maintaining the temperature at about 25°C. After they germinate, move them into the light and 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: It is required to be open on all sides, well ventilated, close to water surfaces, with moist air, and free of coal smoke pollution. On the southwest side of the site, evergreen broad-leaved trees can be planted, with a canopy density of about 0.7. This 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 the temperature. In spring, the amount of water should be directly less; in summer, more is suitable. The plum rain season coincides with orchids sprouting leaf buds, and the potting soil should be slightly dry. After autumn, when the weather turns cooler, the amount of water should be reduced as appropriate, keeping it moist. In winter indoors, it should be dry, reducing the number of waterings, and it is best to water at noon. Orchids can be exposed to light rain, but continuous rain or heavy rain easily causes heart rot and leaf rot, so attention must be paid to rain protection.
3. Fertilizing: For growing 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 through, then cover and seal, let it decompose for one year, and then make it into dry granules. When using, place it on the surface of the pot. If using whole manure, it should also be decomposed for one year, diluted with water, and the residue filtered out before use. Generally, fertilizing starts in May and stops at Liqiu (Beginning of Autumn), following 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 all be placed under open-air sheds. The shade shed requires good ventilation. When orchids have just been brought out of the room 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 maintaining a room temperature of 1°C to 2°C is sufficient. In addition, after orchids are brought out in spring and before they are brought indoors in autumn, attention should 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, the infected potting soil can be removed, and pentachloronitrobenzene powder or lime sprinkled on.
(2) Anthracnose: occurs year-round, and is more rampant in high-temperature, rainy seasons. In addition to improving environmental conditions, the control method is to first spray with 50% thiophanate-methyl wettable powder at 800-1500 times dilution during the onset period, once every 7-10 days, and then supplement with 1% Bordeaux mixture of equal proportions, 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 grasp their natural growth environment conditions, take reasonable measures, and strengthen care and management. According to "Orchid Growing Formulas," it is recorded: "Do not bring out in spring, do not sun in summer, do not dry in autumn, do not wet in winter." This is a summary of our country's experience in growing orchids.
A brief discussion of rational pesticide use for orchids
Fungicides are agents for preventing and controlling crop diseases. When we usually control orchid diseases, we should choose according to the different properties and modes of action of different categories of fungicides. One category is protective fungicides, whose function is to treat plants or the environment in which plants are located before pathogens invade. They need to be used before the plants come into contact with pathogens or before disease occurs in order to be effective, such as Bordeaux mixture, lime sulfur mixture, mancozeb, zineb, etc. There is also another category, therapeutic fungicides. We often come into contact with this type of fungicide. Its characteristic is that it is systemic. The use of this type of fungicide is when the pathogen has already invaded the plant body or the plant is already diseased; at this time it is applied to reduce or eliminate plant disease. Applying the pesticide in the early stage of plant disease will give better results.
The initial and peak stages of disease caused by different pathogens also differ, and are greatly affected by the external environment, especially the growth and development status of the infected crop and temperature and humidity (therefore, we must grow strong orchid plants). When controlling diseases, it is better if everyone can be familiar with the living habits and epidemic patterns of the pathogenic pathogens. Disease control can be carried out according to different seasons and temperature environments, which plays a huge role in the effective exertion of pesticide efficacy. Crop diseases caused by various pathogens are different, and the symptoms of disease are also obviously different, so when choosing fungicide drugs, symptomatic treatment is required. Moreover, the efficacy should be significant and lasting. One should not blindly pursue high efficiency, broad spectrum, or even "universal" agents, as if no matter what kind of disease there is, I only use one drug to deal with it. 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 growing season. 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, etc.
In our daily pesticide use, we should take 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 agents that easily decompose or volatilize under strong light, application should be carried out on cloudy days or in the evening. Different pesticides all have a certain range of use. Only by understanding them deeply and mastering their use characteristics can one correctly select pesticides and achieve twice the result with half the effort. Carbendazim is a systemic fungicide commonly used by everyone. It can control dozens of fungal diseases. Ascomycetes and deuteromycetes are especially sensitive to this drug, but it is ineffective against diseases caused by bacteria and 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 drug is mainly used for downy mildew, Phytophthora disease, and Pythium disease caused by oomycetes, but has very poor effect on diseases caused by other fungi and bacteria. Chlorothalonil is a non-systemic broad-spectrum fungicide. It has a preventive effect 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 soil-borne Pythium is poor. Therefore, frequently change fungicides (Huakang is claimed to be able to kill all diseases; I do not know whether it is true or not, and when using it I do not dare to be careless, and still mix it with other fungicides) to strive for the maximum protection of orchid plants and keep them from being tormented by disease. When orchids grow healthily, orchid friends are also happy.Figure 1 Ring spot disease + anthracnose (Colletotrichum)
Ring spot disease + anthracnose (Colletotrichum), usual preventive pesticide use:
Pesticide name: 77% Kocide wettable powder; mode of action: broad-spectrum protective fungicide; usage: 1000 times dilution / 3-4 times / 7-day interval, spray / leaf underside, leaf surface; can simultaneously prevent: brown spot disease, anthracnose, leaf spot disease, ring spot disease, bacterial brown spot disease;
Pesticide name: 25% Sportak EC; mode of action: broad-spectrum fungicide; application: 1500x dilution / 2-3 times / 8-day interval, spray / underside and upper surface of leaves; also prevents: anthracnose, leaf spot, sooty mold, black spot, round spot, ring rot;
Pesticide name: 80% mancozeb wettable powder; mode of action: broad-spectrum protective fungicide; application: 800x dilution / 3-4 times / 6-day interval, spray / underside and upper surface of leaves; also prevents: anthracnose, leaf spot, sooty mold, black spot, round spot, ring rot;
Ring rot + anthracnose (Colletotrichum) supplementary notes:
1. Because most fungicide formulas for controlling anthracnose are EC formulations or mancozeb types, when applying them you must pay attention to weather temperature and the UV index.
2. When the temperature exceeds 30 degrees, avoid using EC formulations and copper-based fungicides as much as possible; when the UV is too high, try to apply the fungicide before 5 a.m. or after 6 p.m.
3. It is recommended that during normal application you can choose to mix two fungicide formulas together, so that you can achieve treatment and defense in multiple aspects.Image 2: ring rot + leaf spot
Routine preventive application for ring rot + leaf spot
Pesticide name: 80% mancozeb wettable powder; mode of action: broad-spectrum protective fungicide; application: 800x dilution / 3-4 times / 6-day interval, spray / underside and upper surface of leaves; also prevents: anthracnose, leaf spot, sooty mold, black spot, round spot, ring rot;
Pesticide name: 77% Kocide wettable powder; mode of action: broad-spectrum protective fungicide; application: 1000x solution / 3-4 times / 7-day interval, spray / underside and upper surface of leaves; also prevents: brown spot, anthracnose, leaf spot, ring rot, bacterial
Ring rot + leaf spot supplementary notes: before the leaves of an affected orchid have dried up, ring rot is often mistaken for ordinary leaf spot or something similar if not examined carefully. Treating it is [text unclear in source] and is considered a relatively controllable disease.
2. It is recommended that during normal application you can choose to mix two fungicide formulas together, so that you can achieve treatment and defense in multiple aspects.Image 3: mild nutrient deficiency (zinc, magnesium, iron)
Routine preventive application for mild nutrient deficiency (zinc, magnesium, iron): although this is a pathological condition, it is not contagious; during normal fertilizing, supplement some trace elements and fertilizers containing zinc, magnesium, iron and calcium. Supplementary notes for mild nutrient deficiency (zinc, magnesium, iron): during normal fertilizing, supplement some trace elements and fertilizers containing zinc, magnesium, iron and calcium.Image 4: soft rot + black spot
Pesticide name: 72% agricultural streptomycin sulfate wettable powder; mode of action: antibiotic fungicide; application: 800x dilution / 2-3 times / 7-day interval, spray, root drench; also prevents: bacterial brown spot, soft rot;
Soft rot + black spot supplementary notes: because this is a condition in which fungi and bacteria occur at the same time, two different fungicides must be mixed and used together. Since the two fungicides each have their own application concentration multiplier when mixed, this often troubles novice orchid growers. Here is a supplementary explanation again: ratio: for 100 jin of water, use the bacterial one, streptomycin sulfate at 500x, mixed with the fungal one, carbendazim at 1000x.
1. For 100 jin of water, streptomycin sulfate at 500x equals a required amount of 100 grams of streptomycin sulfate.
2. For 100 jin of water, carbendazim at 1000x equals a required amount of 50 grams of carbendazim.
3. That is, using 100 grams of streptomycin sulfate equals 500x, plus 50 grams of carbendazim equals 1000x, put both into 100 jin of water and mix for use; only then is the pesticide dosage correctly prepared.Image 5: leaf-tip anthracnose + leaf blight
Routine preventive application for leaf-tip anthracnose + leaf blight
Pesticide name: 25% propiconazole EC; mode of action: broad-spectrum systemic fungicide; application: 1500x dilution / 2-3 times / 8-day interval, spray / underside and upper surface of leaves; also prevents: brown spot, round spot, anthracnose, leaf spot, leaf-tip blight;
Pesticide name: 10% Score water-dispersible granules; mode of action: broad-spectrum systemic fungicide; application: 3000x dilution / 2-3 times / 8-day interval, spray / underside and upper surface of leaves; also prevents: brown spot, leaf spot, black spot, round spot, leaf blight, ring rot, leaf-tip blight, sooty mold;
Leaf-tip anthracnose + leaf blight supplementary notes: because this is a cross co-infection of two pathogens, it is recommended to use two fungicides for relatively simple control. Regarding the mixing method for the two fungicides, it is repeated here once: when two conditions occur at the same time, two different fungicides must be mixed and used together. Since the two fungicides each have their own application concentration multiplier when mixed, this often troubles novice orchid growers. Here is a new supplementary explanation: ratio: for 100 jin of water, use the bacterial one streptomycin sulfate at 500x mixed with the fungal one carbendazim at 1000x.
1. For 100 jin of water, streptomycin sulfate at 500x equals a required amount of 100 grams of streptomycin sulfate.
2. For 100 jin of water, carbendazim at 1000x equals a required amount of 50 grams of carbendazim.
3. That is, using 100 grams of streptomycin sulfate equals 500x, plus 50 grams of carbendazim equals 1000x, put both into 100 jin of water and mix for use; only then is the pesticide dosage correctly prepared.Image 6: leaf-margin black spot
Routine preventive application for leaf-margin black spot
Pesticide name: 80% mancozeb wettable powder; mode of action: broad-spectrum protective fungicide; application: 800x dilution / 3-4 times / 6-day interval, spray / underside and upper surface of leaves; also prevents: anthracnose, leaf spot, sooty mold, black spot, round spot, ring rot.
Pesticide name: 10% Score water-dispersible granules; mode of action: broad-spectrum systemic fungicide; application: 3000x dilution / 2-3 times / 8-day interval, spray / underside and upper surface of leaves; also prevents: brown spot, leaf spot, black spot, round spot, leaf blight, ring rot, leaf-tip blight, sooty mold;
Pesticide name: 25% Sportak EC; mode of action: broad-spectrum fungicide; application: 1500x dilution / 2-3 times / 8-day interval, spray / underside and upper surface of leaves; also prevents: anthracnose, leaf spot, sooty mold, black spot, round spot, ring rot;
Pesticide name: 50% Sporgon wettable powder; mode of action: broad-spectrum fungicide; application: 2000x dilution / 2-3 times / 8-day interval, spray / underside and upper surface of leaves; also prevents: anthracnose, leaf spot, sooty mold, black spot, round spot, ring rot;
Leaf-margin black spot supplementary notes: in fact, many of the fungicides used for orchid leaf diseases are similar in nature, but as a professional introduction we have no choice but to present all the conditions for orchid growers to understand. In general, the best fungicide choices are the two types with broad-spectrum and systemic properties.
Experience-based reminder: in my experience, the key task when buying pesticides is to choose based on the manufacturer's reputation and the labeled ingredients, so as to avoid the psychological comfort of thinking you have a fungicide when the result is fake ingredients, causing the disease to go uncontrolled and missing the golden window for treatment.
Experience-based reminder: the second cause of harm is this: thinking that these pesticides may have insufficient active ingredients, one instead increases the concentration and multiplier. Who would have known that this time you bought the real product, and as a result, once the multiplier is increased, it causes severe phytotoxicity. Haha! You can only look to heaven speechlessly.Image 7: blight
Routine preventive application for blight
Pesticide name: 72% Curzate wettable powder; mode of action: systemic fungicide; application: 1500x solution / 2-3 times / 10-day interval, drench the roots and stems; also prevents: blight
Pesticide name: 50% Acrobat wettable powder; mode of action: systemic fungicide; application: 12500x dilution / 2-3 times / 10-day interval, drench the roots and stems; also prevents: blight
Supplementary notes on treating blight once infected:
1. During the peak period of disease outbreak, continuous preventive application of chemicals is necessary. Having understood the characteristics of stem rot, we can only use targeted fungicides.
2. 72% agricultural streptomycin sulfate soluble powder at 800x solution, 77% Kocide powder at 1000x solution, spray on the underside and upper surface of leaves and the crown.
3. Milfuram (EC) 1500x + oxytetracycline (powder) 2000x + dimethomorph (powder) 2000x solution, spray on the underside and upper surface of leaves and the crown.
4. Antaison 500x + Milfuram 1500x + streptomycin sulfate 500x solution, spray on the underside and upper surface of leaves and the crown. (When applying fertilizer or pesticide, you must spray the underside of the leaves, because plants absorb through the stomata on the underside of the leaves.)
5. Every 20 days or so, use Dexon 800x + oxytetracycline 3000x solution for a thorough root drench.
6. Fungicides must be rotated and alternated so as not to produce resistance and delay treatment of the disease.Basic principles of orchid cultivation and management techniques - orchid cultivation techniques
1. Preparation of growing medium. Planting orchids requires a specially made growing medium, also called orchid soil. The growing medium for orchids should preferably be loose and airy, well drained, with an appropriate amount of fertilizer, and free of 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, and there are quite many types. Some components seem unrelated to soil, but they are all substrates on which orchids rely to stabilize the plant and for growth and development.
(1) Growing medium formulas.
In East China, orchid growers generally prefer to use orchid soil from places such as Shaoxing and Yuyao. In recent years, the Emei He Wang Pai Xian Tu has also been welcomed by people, but these growing media are limited in quantity and expensive, and can only be used for repotting. For large-scale ground planting, hundreds or thousands of tons of growing medium are needed, so one can only use local materials. After many years of practice and repeated screening, we determined that the best formula is: four parts yellow sand soil, four parts sawdust, two parts river sand; if it is yellow loam soil, then one part river sand, one part sawdust, one part yellow loam soil. All are thoroughly mixed. The pH value of the prepared growing medium should be between 6.5-6.8, loose and airy, with excellent water retention and air permeability, and comprehensive nutrition. River sand and sawdust serve to conduct water and air; the sawdust is decomposed by bacteria and can slowly release nitrogen, phosphorus, potassium, etc. Yellow loam soil also contains a variety of trace elements. After years of observation, this formula is very suitable for orchid growth. It is especially suitable as a substrate for the domestication and cultivation of wild orchids. It is suitable for Cymbidium goeringii and Cymbidium faberi, and is also very ideal for Cymbidium ensifolium and Cymbidium kanran. Both the flowering rate and stress resistance increase significantly.
(2) Bamboo root soil.
This refers to the soil at the roots of bamboo clumps that have been planted for many years. Because of the spreading growth of bamboo rhizomes and bamboo roots, as well as the decomposition of bamboo leaves and shoot sheaths, this soil becomes loose in structure, well drained, 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 number of years the bamboo clump has been planted, the longer the time, the more fully the effects of bamboo roots, bamboo leaves and bamboo rhizomes; third, the distance from the bamboo stump, the closer the soil is to the bamboo stump, the better.
(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 it up, and let it decompose, and it becomes vetch chaff soil. Its preparation method is: choose a rain-sheltered site, spread a layer of soil, then a layer of vetch chaff, pour once with *manure water, and pile up layer by layer in this way; after the pile is finished, sprinkle water on the surface to moisten it, then coat it with thin mud to seal it. After piling and fermenting for half a year, it can be used.
When using, mix it into other growing media in proportion.
(4) Leaf mold.
Use fallen leaves or green grass and tall stalks, pile them up and water or pour fertilizer, coat with thin mud to seal, and after decomposition and screening it is made. It is best to use green grass that has not set seed, and it must be fully decomposed to kill pests, diseases and weed seeds, otherwise there will be many weeds in the orchid pot later.
(5) Mountain soil.
That is, the mountain forest soil where wild orchids originally grow. It is formed by dead branches and fallen leaves accumulating and rotting over many years and mixing with the soil. The naturally formed leaf mold contains rich humus, is loose and airy, and is very suitable for orchid growth. When transportation is convenient, digging up mountain soil in large quantities to plant orchids is relatively simple and economical, and it is even better for domesticating raw orchids. The humus soil under broad-leaved forests, especially the leaf mold under chestnut trees, is a very ideal soil for orchids.
(6) Pond mud.
In conjunction with winter repairs of ponds and fish ponds, the mud is dug out, dried in the sun, and then broken into fine particles. It can be used to cultivate all flowers, including orchids.
(7) Field soil.
That is, choose loose topsoil from the field, mix in a little sandy soil or a small amount of rice husk ash, then add some decomposed compost or fermented and decomposed organic fertilizers such as soybean cake and rapeseed cake, to promote improvement of soil structure and enhance fertilizer efficiency. After repeatedly turning and mixing the pile evenly, then sieve it. This kind of soil is nearly neutral and not as good as humus soil. Therefore, it is only used reluctantly when there is no suitable humus soil or mountain forest sandy loam, and it is mostly used for cultivating common orchid varieties.
(8) Cow dung soil.
Crush and grind fermented dried cow dung into fine powder, and mix it into sandy soil or the topsoil of field soil in a 1:3 ratio. It is best to select cow dung from cattle fed dry feed in winter, because although the dry forage is finely broken after rumination in the cow's stomach, it is still elastic, and as plant fiber it contains certain nutrients. This kind of cow dung soil is soft and rich in fertilizer, and is extremely suitable for the air-loving nature of orchid roots. In Taiwan's orchid-growing circles, people often use this cow dung soil as a filling material for cultivating terrestrial orchids, with very good results. Abroad, for cultivating terrestrial orchids, generally 5 parts humus soil or leaf mold plus 1 part sand is used; or 3 parts peat soil plus 1 part river sand, mixed with crushed dried cow dung, and used after thorough mixing. The cultivation substrate for epiphytic orchids is mainly moss and ferns, with a small amount of tree leaves, small pieces of charcoal and crushed dried 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 the pathogens and insect eggs in it. Before use, the growing medium should be tested and adjusted for its pH value. For soil that is too acidic, lime can be used to adjust it. For soil that is too alkaline, calcium superphosphate, ferrous sulfate, etc. can be mixed into the soil. In short, it is appropriate to control the soil pH value at neutral and slightly acidic (that is, pH 5.5-7). Using organic fertilizers, such as green grass and tree leaves composted into fertilizer, and adding them to the soil to change the soil pH is a relatively good method. In addition, before planting orchids, the nutrient soil should be sieved and graded, separating large particles from small particles.
When planting orchids, place the large particles at the bottom of the pot to facilitate drainage. At the same time, the degree of dryness and wetness of the soil should also be adjusted well: it should not be too wet or too dry. It is best to ball the soil in your hand and squeeze hard so that the soil can form a ball; then open your hand and shake it a little, and the soil disperses into granules again. Only this degree of dryness and wetness is suitable.
2. Preparation of the orchid-growing site. 1. Productive ground planting. The original environment for terrestrial orchids is growing among secluded mountain forests and valleys, with high, refreshing terrain, shade from trees, and a humid microclimate. The temperature difference is small and the air is clean.
When introducing and domesticating them, one should first simulate their wild environment so that they can be cultivated with abundant flowers and lush leaves. At present, with industrial development and urban modernization, greening work cannot keep up accordingly for the time being, and they are affected by pollution from factories and vehicles. Therefore, orchids cultivated in cities are not as robust as those grown in the suburbs. There is a gap with the native environment of wild orchids, and a great difference from the meteorological factors of the native places of Cymbidium kanran and Cymbidium ensifolium, so careful design was made for the domestication and orchid-planting site and practical arrangements were made for adjusting environmental factors.
The orchid nursery covers an area of about 1.5 sq m, rectangular in shape. In the nursery there is a rectangular water pond used to store rainwater. In the nursery, every 2.5 m or so, a 2.5 m high moso bamboo pole is fixed, and bamboo poles are tied horizontally on top to form a frame, used to lay and tie the first layer of shade net. At 20 cm below the first layer of shade net, another horizontal thin moso bamboo pole is placed, used to lay the second layer of movable shade net. The first layer of shade net is basically fixed from spring to autumn, and the second layer can be rolled up or spread out as needed. Carefully adjust light and temperature. The seedbed width is 1.2 m, length 12-16 m (depending on terrain), height about 30-40 cm (5-7 bricks high), the seedbed interval is 50 cm, and the passage width is 130 cm. This facilitates daily management. In winter, a plastic greenhouse is tied over every two beds for warmth. On snowy days, pay attention to clearing snow to avoid too much snow crushing the plastic greenhouse. About every mu (one mu is about 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 set up about every 4 m inside the plastic greenhouse, mainly for heating.
2. Open-field cultivation
(1) Ground planting of cymbidiums in 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 over the soil surface at the roots to prevent frost injury to the orchid roots. If there is severe cold, it is also necessary to lay straw curtains or other soft coverings over the leaf clusters to prevent cold damage. For this kind of ground-planted orchid cultivation, apart from strengthening management and protection during the hottest midsummer, it can generally be extensive and allowed to grow naturally. Orchids planted in the open field are all common varieties without petal-type classification. In the following spring, after the weather turns warm, the cold-protection coverings can be removed. After years of growth, as long as it is watered and fertilized in a timely manner, its adaptability is still relatively strong, and it can bloom abundantly every year, with a delicate fragrance carried far, making it a fine item to adorn the countryside.
However, when arranging ground-planted orchid cultivation, besides considering the quietness of the layout
(2) Pot cultivation of orchids.
This also refers to growing orchids under a shade shed.
Whenever orchids are grown in pots, it is best to use clay pots, that is, unglazed earthenware pots. They have good air permeability, can filter water, and are cheap. They are economical and practical utensils for growing orchids. But clay pots are rather rough and not beautiful, so they are unsuitable for exhibition. Porcelain pots or glazed pots are beautiful in appearance, but their air permeability and water filtration are very poor. If used for long-term orchid cultivation, they easily rot the orchid roots, making it difficult for the orchids to grow vigorously. Therefore, when using porcelain or glazed pots to grow orchids, more drainage tiles must be placed at the bottom of the pot, or fillers such as clam shells; moreover, watering must be controlled and not excessive. If clay pots are used to grow orchids, they can be slipped inside larger porcelain or glazed pots when participating in exhibitions. Yixing purple clay pots are beautiful and elegant in appearance, and also have a certain air permeability, so they are relatively suitable for growing orchids. Newly bought orchid pots must be soaked in water for several days, especially clay pots just out of the kiln, which must be allowed to absorb enough water to completely eliminate their fiery dryness. Generally, for orchid cultivation, newly planted orchids mostly use new pots, while repotting mostly uses old pots. Whenever orchids are grown in pots, it is best not to place them directly on the ground, because they are easily disturbed by pests and overgrown weeds. Especially in hot summer, when the blazing sun is scorching and ground temperature rises, it harms the orchid plants; whenever there are thunderstorms or during the plum rain season, the humid heat rises even more, easily steaming the orchid roots; moreover, being close to the ground, ventilation is poor. This is beneficial for aerial root growth. To reduce the above effects, the orchid pots can be placed on an orchid stand built from cement boards, which facilitates upward and downward convection, continuously supplies fresh air, promotes orchid respiration, enhances metabolic function, accumulates nutrients and energy production, makes orchids grow robustly, and also avoids harm to orchid roots by ants, slugs and the like. If limited by conditions, an empty clay pot can be inverted upside down on the ground, and then the potted orchid placed on top.
3. Orchid room cultivation. The orchid room is mainly for overwintering terrestrial orchids.
Different types of orchids have different ecological habits, so the time for moving them indoors for overwintering and the room temperature requirements are also different. For terrestrial orchids, as long as the temperature is not lower than 7°C-8°C, most can be cultivated in the open. In Jiangsu and Zhejiang, the habit is that after the Beginning of Winter, Cymbidium ensifolium, Cymbidium kanran and Cymbidium sinense, which require slightly higher temperatures, are moved indoors for cultivation, while some Cymbidium goeringii and Cymbidium faberi with flower buds are moved under the eaves or to cold-protected places to avoid attack by early frost and prevent effects on flower bud development. After Light Snow, potted orchids cultivated from pseudobulbs and thin, weak small plants, especially orchids with plain-center petals, are gradually moved indoors and placed on orchid stands near windows so as to receive sunlight. After Great Snow, all potted orchids are moved indoors for maintenance. Before orchids enter the orchid room, first wash the area around the orchid pots clean, which can prevent mud contamination with insect eggs, mold, etc., and also looks clean and elegant. When placing orchid pots, pay attention to reasonable arrangement, which is convenient for sunlight penetration and also conducive to ventilation. When terrestrial orchids overwinter indoors, the key is to master temperature and humidity well. Generally, room temperature should be maintained above 7°C-8°C, and for Cymbidium sinense it is most ideal to maintain 10°C-15°C. After the orchid pots are brought indoors, if the weather is not yet severely cold and freezing, the south-facing windows should be opened around noon, and a small vent on the north side should be opened, to facilitate indoor air circulation. In the evening, if the indoor temperature is still above 5°C, the small north and south vents can be opened slightly; if it is below 5°C, all windows should be closed. In deep winter, only around noon on windless, sunny days should the windows be opened slightly for a little ventilation, and once the sun shifts a little, the doors and windows should be closed, and straw curtains or cotton cloth curtains hung up toward evening. If the temperature continuously drops below 3°C-5°C, a coal stove with a chimney pipe can be used for heating. After the Beginning of Spring, the climate gradually warms, and on clear noons all the doors and windows of the orchid room can be opened wide, but attention should be paid to changes in temperature; in the afternoon when the temperature gradually drops, the south windows should be half open and half closed; before nightfall they should all be closed well again.
During this period, the orchid room temperature should preferably be kept at around 10°C. If the temperature is on the high side, it will cause early-flowering varieties of Cymbidium goeringii to bloom earlier, and the flowers are also prone to withering early. In early spring, it is even more necessary to prevent a late spring cold snap, which affects flower bud growth and may even freeze the orchid roots.
After Awakening of Insects, all Cymbidium goeringii and Cymbidium faberi without flower buds can be taken out of the room and placed on open-air stands, with reed curtains added on the frames at night to prevent frost damage. All kinds of orchids with flower buds should still remain in the orchid room for maintenance, and only after Pure Brightness can they be moved outside for cultivation; but at night attention should still be paid to preventing late frost. During the period of indoor orchid cultivation, especially in severely cold seasons, special attention must be paid to the dryness and wetness of potted orchids. The pot soil should preferably be dry. When watering is needed can be judged 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 potted orchid down and place it on the ground, and water along the water groove at the pot rim. Never let water soak into the leaf clusters. The orchid pot can also be placed in a water vat and shallowly soaked for a few minutes, with the water limited to reaching the waist of the pot. When watering, if water soaks into the leaf sheaths, it should be promptly wiped away with a dry cloth, or allowed to dry in the sun before the plant is moved back indoors. Because orchids are placed indoors for a long time, a lot of dust often attaches to the leaf surface, hindering metabolism. On clear, warm days, around noon, move the pots outdoors into the sunlight and use a fine-hole spray pot to spray and clean the leaf surface, washing away dust and dirt, and after the water marks dry, move them back indoors. If the water marks are not dry, the wet parts of the orchid leaves are prone to turning black and withering. During indoor orchid cultivation, during the heating period, the indoor temperature is often on the high side, the leaf clusters appear dry, the soil surface in the pot is dry and loose, or the moss on the pot surface looks withered. Then water should be sprayed promptly on the passages and walls to allow evaporation, so as to regulate temperature. In short, for indoor orchid cultivation, whether it is the orchid plants in the pot or the moss on the pot surface, it is best to keep them green and lush. If you are an amateur orchid grower, due to limited conditions, you can use a south-facing sunny spot along a wall outdoors, 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 according to the number of pots. On the sloped surface of the ground box, install a wooden-framed glass window or plastic film window that can be opened and closed as needed. For orchids with long and tall leaves, place them in a higher position near the wall with more space, and they should be placed on inverted empty flower pots, or on bricks, strips of wood, or cement boards stacked to a suitable height. Low orchid pots are arranged row by row toward the front, and all leaf tips or the tops of curled leaves must not touch the glass or plastic film of the window surface. In severely cold seasons, whenever the temperature is too low or on snowy and windy days, the sloped window must be covered with enough straw curtains or other coverings to prevent cold air from entering. When the weather is clear and mild, especially after the Beginning of Spring, when sunlight shines, the cold-protection straw curtains can be removed; when the midday sun is strong and the temperature is slightly higher, the covered window can be lifted open a crack to regulate fresh air. After the sunlight shifts, the covered window should be closed immediately. In daily management, great attention must be paid: excessive water droplets must not condense on the covering window glass, to prevent them from dripping into the leaf clusters; the wet parts often turn black and rot, and may even die.
3. Planting orchids. 1. Planting timing. Whether repotting or newly planting, the choice of timing has a great influence on the survival, growth vigor and development of orchids. Therefore it is very important. Generally, the relatively suitable time is the orchid's dormancy period, that is, March-April, before the new buds emerge from the soil; in terms of solar terms, it is between the Spring Equinox and Pure Brightness. If done after the new buds emerge from the soil, the operation is very inconvenient, and a little carelessness may break or injure the new buds. When the orchid's dormancy period is about to end and the new buds and new roots are at the stage of being about to grow but not yet grown, planting at this time is best; shortly after planting, they can send out roots and buds and resume normal growth. If planted too early, the orchids are not easily revived after planting; if they encounter low temperature, cold waves, late frost or spring thunder, frost damage is often caused. In the Yangtze River basin, orchid rooms are rarely heated in winter. Winter is very cold, so division in severe winter is not advocated. To make the operation convenient when dividing, the soil can be allowed to dry appropriately before division. This makes the roots turn white and produce inconspicuous shrinkage, making the originally brittle and easily broken fleshy roots soft and pliable, so that when dividing and potting, the roots are not broken too much. In larger orchid nurseries, the planting workload is large and takes a long time from start to finish. 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 that grow well and are free of pests and diseases should be selected.
After 2-3 years of cultivation, orchids need soil replacement or repotting, and at this time division propagation should be combined with it. When repotting, support the bottom of the flower pot with the left palm, carefully extend the fingers of the right hand into the orchid seedling leaf cluster to block the pot soil, then lay the orchid pot on its side, tilt the pot body sideways facing the person, and let the lower edge of the pot mouth touch the ground. At this time, lift the pot slightly upward with both hands at the same time, so that the lower edge of the pot lightly taps the ground, loosening the pot soil, rotate the pot body, change the contact point where the lower edge of the pot mouth taps the ground, and let the pot soil gradually loosen evenly and separate from the flower pot. Support the orchid plant with the right hand, and remove the flower pot with the left hand. If the orchid plant is too tall, it is better to tap the lower edge of the pot mouth at the edge of a wooden chair or cement platform, so that 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 open, causing the orchid root system to break. Then carefully pat the soil ball gently to loosen it, and gradually shake off the old pot soil. Carefully grasp the pseudobulbs to avoid injuring the leaves and tender buds, especially protecting the root tips. Cut off leaves that have already turned yellow and withered, decayed bracts on the pseudobulbs, and rotted, dried, hollow old roots. However, for pseudobulbs with new buds, the leaves should be retained as much as possible to promote good growth of the new buds. For the larger clumps that have been selected and cleaned, find the natural gap where the two pseudobulbs are relatively far apart and easily loosened when shaken by hand, cut the two pseudobulbs apart, which predecessors called opening the road, then hold the bases of the two clumps with both hands, shake gently and pull slowly along the road to divide them into two clumps. Prune the separated orchid clumps appropriately, then soak them in a 800x water-diluted thiophanate solution for 10-15 minutes; only the roots should be soaked, not the leaves; a 1000x potassium permanganate solution can also be used for disinfection. Note that only the wounded parts should be disinfected, then dry the orchids in a cool, ventilated place. When the orchid roots become soft and easy to bend, they can be planted. Generally, when the weather is clear, drying for half a day is enough, but of course they must not be dried too much.
3. Planting procedure. For separated orchid clumps, do not divide them too sparsely. Each clump should have at least 3-5 seedlings, and it is best to keep one-year-old plants, two-year-old plants 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, with the large gaps filled with mud particles or bean-sized stones, generally about 1/2-1/3 of the pot's internal height. The remaining clear height above is about 10-15 cm, reserved for the growing medium layer. Its specific height should be determined according to the orchid species, the length of the 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 proved that some new roots can grow well in the gaps of the padding layer.
(2) Planting.
On the padding layer, first fill in 2-3 cm of growing medium, press it slightly firm with the hand, then place the orchid upright on it. According to the size of the plant and the flower pot, several single plants, 2 clumps, 3 clumps or more clumps can be planted in one pot. 3 clumps are suitably planted in a tripod arrangement. 4 clumps can be planted in a square. 5 clumps are suitably arranged in a plum blossom shape. The orchid roots should spread naturally, and the leaves should spread in all directions. Slowly place the orchid roots into the pot so that they spread naturally and try not to rub against the inner wall of the pot. After the orchid plant is put into the pot, gradually fix the posture of the orchid plant. For one clump per pot, the old pseudobulbs should be placed toward one side, so that the new buds have room to develop. For multiple clumps per pot, the old pseudobulbs of each clump should be gathered relatively toward the middle of the pot, so that the new roots and new buds developing outward each have enough space.
(3) Filling soil.
When planting, hold the leaves with one hand and add nutrient soil with the other, hold the base of the orchid plant and lift it slightly upward to spread the root system, while shaking the orchid pot. Let the growing medium get deep into the root zone; continue adding soil and shaking the orchid pot to adjust the position and height of the orchid plant. Press along the pot edge with the hand, but do not press too hard and injure the roots. Continue adding soil and pressing until the pot surface soil is 2-3 cm above the pot rim, slightly in a steamed bun shape. The growing medium should cover all the orchid roots, up to the base of the pseudobulbs. As for the depth of soil filling, tradition holds that Cymbidium goeringii should be shallow and Cymbidium faberi should be deep, but generally the standard is not to bury the leaf bases on the pseudobulbs. When newly collected orchids grew in the wild, they left obvious marks on the plant above and below the soil surface, and these marks can be used as the standard. The size of the flower pot should also match the size and number of the plants: neither a large pot with few and small plants, nor a small pot with many and large plants. Generally, the number of plants should be based on the principle that after 2-3 years they will just fill the pot. The size of the plant should match the height of the pot. This is both conducive to growth and meets ornamental requirements.
(4) Top dressing.
After planting is completed, spread a layer of small stone particles or green moss on the surface of the pot soil, preferably high-quality moss from under the forest. It is both beautiful and can regulate moisture, and can also protect the leaf surface from being polluted by muddy water, and prevent new buds from being infected by pathogens in the soil and rotting at the center; in addition, it can also reduce the washing away of pot soil by rainwater and keep the pot soil loose.
(5) Watering.
After planting is completed, water for the first time immediately. The pot soil must be thoroughly wet. The water droplets should be small and the impact force should not be strong. If placed in a water basin to soak, it must not be soaked too long. Once the pot soil is soaked wet, immediately take the orchid pot out, then move it to a shaded place for maintenance.
4. Maintenance management after planting. Although mastering the skill of planting orchids is certainly very important, managing and maintaining orchids well is even more difficult, hence the saying "three parts planting, seven parts maintenance." Maintaining orchids requires understanding the environment, accumulating maintenance experience, and patience and care. The most important thing is to master the laws of orchid growth and development: when they sprout, when they grow leaves, when they bloom, and when they go dormant. Then carry out maintenance management from aspects such as 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 and firm but not stiff.
Orchids are moving and lovely, but good flowers do not come often, and there is no way to keep a flower from falling; yet orchid leaves remain green through the four seasons, forever full of vitality, giving people enjoyment that continues all year round. The elegance of orchids is both displayed in the flowers and entrusted to the leaves.
And lush leaves are also the prerequisite for good flowers. When the leaves are healthy and lush, the plant itself produces abundant nutrients, so the flowers are numerous and beautiful. If the leaves are damaged while the flowers are many, it is merely a sign of rapid decline. The key to cherishing leaves is first of all to control the degree of shading, air humidity, appropriate water and fertilizer, and maintain good ventilation. Make the orchid leaves lush and sound, green and glossy. Also strengthen pest and disease control, and prevent wind, rain attack and mechanical damage. In addition, preserve the leaf tips: the ends of orchid leaves are like sword tips, brush tips, or eyebrow tips, able to convey meaning and spirit. Losing the leaf tip makes them appear abrupt and dull. To preserve the leaf tips, the key is to ensure that the orchid's required water and nutrients are sufficient, that the pot soil is loose and airy, and therefore that the root system is well developed and intact and the plant grows vigorously, with no scorched tips. Some people say that a sign of orchids being well grown is that the leaf tip can pass through the eye of a needle, which refers to the leaf tip being intact and the tip undamaged. The shape of leaf tips differs among different orchid species: some are acuminate, some are blunt and rounded, some are notched, and some are upturned. As for leaf color, some orchid varieties have gold tips or silver tips (that is, the leaf tips are yellow or white), showing their preciousness and rarity. This is another layer of interest in leaf appreciation regarding leaf tips. In maintenance, pay attention at ordinary times to protecting orchid leaves; during operations be light and careful, do not bump the orchid leaves, and maintain their natural posture.
Carefully clean contaminated leaves, and sprayed water must not accumulate in the center of the leaf cluster. Withered yellow old leaves and diseased leaves should be cut off in time. For partial cutting of orchid leaves, a slanted cut can be made at an appropriate place, and the resulting pointed angle should be less than 30. Some also cut twice, but it must not be cut flat across.
2. Protecting flowers. After the flower buds emerge from the soil, if there are too many, they consume excessive nutrients from the mother plant, hindering the formation and robust growth of leaf buds. The excess thin and small flower buds should be removed early. For each orchid seedling, it is enough to keep one flower bud.
Each pot should preferably retain 3-5 flower buds. Retain flower buds appropriately according to the orchid variety, the size of the pot, and the number of seedlings. In order to protect and develop precious varieties, all flower buds can also be removed to let them multiply abundantly. During the period from flower bud elongation to flowering, moderate light should be maintained, so that the flower color is fresh and full, rich in luster and with sufficient fragrance. If the light is too weak, the flower color is pale and lacking in luster. If the flower remains open too long, it consumes nutrients and hinders sprouting and leaf growth as well as flowering the following year. The flowers of Cymbidium goeringii bloom for about half a month, and after they fade the flower scape should be cut off in time. For Cymbidium faberi flowers, when the last flower of the inflorescence has been open for 1 week, the inflorescence should be cut off. When removing the flower scape, steady the leaf base with one hand and press the flower scape to one side with the other, and it can be broken off from the base and pulled away, or it can be cut off. The removed flowers and grass can be placed in a vase and still enjoyed for many days. Generally, orchids are not allowed to be pollinated and set seed after flowering, especially those that are not very robust and precious varieties, otherwise it affects flowering the following year. If hybrid breeding is to be carried out, artificial pollination should be performed at the appropriate time. And the mother plant should be carefully managed so that its seeds are full and mature.
3. Temperature. Most of our country is in the temperate and subtropical zones, while orchids generally come from places with mild and humid climates, relatively high annual average temperatures, and long frost-free periods. In northeast and northwest China, orchids are rarely grown, mainly because of temperature constraints. The northernmost distributed Cymbidium plants in our country are Cymbidium goeringii and Cymbidium faberi. On their distribution line, there is frost in winter or short-term snow cover, and summer temperatures are relatively high. However, because orchids mostly grow in mixed broad-leaved and coniferous forests or in bamboo forests, the trees both block the summer sun and resist the winter cold wind; even in places covered with snow, the effect on orchids is not great, because the snow actually plays a role in protecting orchids through the winter, and the ground temperature under the snow is generally not lower than 0°C. In our introduction and domestication of Cymbidium ensifolium and Cymbidium kanran, we have already moved them 600-1000 km northward from their native places, and on a large scale of ground planting. It can be seen that the survival ability and adaptability of orchids are still relatively strong. In most areas of northeast, northwest and north China, winters are too cold, and outdoor orchid cultivation is unsuitable. From mid-to-late October to late April of the following year, for half a year, orchids all need to be moved indoors or into greenhouses for cultivation. In the lower Yangtze region, orchids also need to be cultivated indoors or heated in sheds in winter. In Fujian, Guangdong, Guangxi, Yunnan, Sichuan, Taiwan and other provinces and regions, Cymbidium kanran and Cymbidium ensifolium generally do not need to overwinter indoors in winter. In Jiangxi, Hunan and parts of Sichuan, certain measures are still needed in winter to protect orchids.
Orchid temperature requirements: 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 and 13°C-0°C at night.
During the winter dormancy period of orchids, the temperature can be lowered. For example, for Cymbidium goeringii and Cymbidium faberi in winter, the minimum nighttime temperature requirement is 4°C-6°C, and dropping to 0°C is also acceptable. The plant leaves can even drop to minus 2°C-3°C under dry conditions without harm. 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, and concluded that a low temperature of 12°C-13°C is enough to promote flower bud differentiation, and the relationship with day length is not very great. But the more light the orchid receives, 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 regulating temperature are mainly 3 aspects, namely: preventing cold in winter, preventing summer heat, and changing the flowering period. When the winter temperature is below 0°C, orchid leaves and flower buds are prone to cold injury, with water-soaked black spots appearing on the leaves 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 that are too high are also not good, because orchids are in a dormant state in winter, and too high a temperature will disturb dormancy. In summer, if the temperature is too high, orchids suffer from summer heat, the leaves turn yellow, become rough and lack luster, and are prone to disease attack, often with the leaf base beginning to rot. The flowering period of orchids is very obviously affected by temperature; under general conditions, appropriately raising the temperature can make them bloom earlier. For example, under cultivation conditions in plains and cities, the flowering period of orchids is often 15-30 days earlier than under their original wild conditions. Using this biological characteristic, the temperature can be appropriately regulated 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; after they pass 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 step by step. Experiments show that a sharp temperature increase instead produces an inhibitory effect and delays the flowering period.
Methods of regulating temperature:
Temperature has an enormous influence on the growth and development of orchids. If the temperature is too high, respiration speeds up and more nutrients are consumed; if it is too low, enzyme activity declines, synthesis is reduced, and growth and development slow down. What matters is that a daily temperature difference and a seasonal temperature difference must form, because only then can the orchids sprout and bloom. In regulating temperature during domestication and cultivation, we adopt the principle of approximating the conditions of the orchid's place of origin. In summer we shade the orchid nursery with a double layer of shade netting, which has a clear cooling effect: when the air temperature reaches as high as 35°C, the temperature in the nursery is only 31°C-32°C. In winter we use plastic sheds to keep them warm: when the air temperature drops to 0°C, the inside of the plastic shed can still remain at 6°C-8°C, and the temperature difference in winter is smaller than in the open ground, which both favors nutrient storage and prevents freezing damage. Besides building earthen orchid sheds and orchid rooms, temperature can also be regulated by planting trees, shrubs, vines and lawns around the orchid nursery; in summer these can absorb part of the solar radiant heat, and in winter they can slow the loss of heat from the ground and the air. Take lawn as an example: according to measurements, in winter the air temperature over grassland is higher than over bare mud ground, with a maximum daytime difference of up to 4.4°C, which helps avoid freezing damage; while in summer the air temperature over grassland is much lower than over cement ground, which helps prevent heatstroke and lower the temperature. In summer it is advisable to spray or sprinkle clear water in the air, on the ground surface, on the flower platforms and on the orchid leaves. This is because water absorbs part of the heat when it evaporates, which can cool things down and prevent heat damage; likewise, enlarging the water surface nearby has the same effect, such as with ponds, reservoirs, ditches and water vats. In a greenhouse, curtains must be hung on the glass to block light and prevent heat. In hot weather, even more attention should be paid to ventilation and to strengthening air convection for heat dissipation, lifting part of the shed covering locally; in an orchid room, open the doors and windows to avoid the accumulation of hot air. In regulating temperature, besides air temperature, soil temperature should also be noted. Orchid roots grow in the soil, and the temperature of the potting medium has a direct effect on their physiological functions. Under ordinary conditions, soil temperature and air temperature are positively correlated: when the air temperature is high, the potting soil temperature rises accordingly, but the process of change is relatively slow. First, direct sunlight must be prevented from hitting the pots and heating the soil and pots until they burn the orchid roots lying close to the pot walls; also, when watering, the water temperature should be close to the soil temperature and should not differ too greatly. There is another question worth exploring, namely the relationship between artificial protection and the orchid's own adaptive capacity. Like all plants, orchids have their own adaptability to the external environment. They are not inherently delicate. Therefore, when orchid growers protect orchids from heat and cold, their measures should be kept moderate. Shading too densely and for too long will inevitably weaken their resistance. In our nursery, the Cymbidium kanran and Cymbidium ensifolium introduced and domesticated from more than 600-1000 kilometers to the south, besides receiving protection, are also gradually allowed to strengthen their stress resistance and adapt little by little to the new environment.
4. Humidity. Humidity generally refers to relative humidity, commonly expressed as a percentage.
Orchids have no fibrous roots, still less root hairs, so the surface area for absorbing water is small; on the contrary, orchid leaves grow in clusters. Transpiration from the leaf surface is relatively large, and only when the air is humid can the balance between water absorption and transpiration be maintained. In the growing season at the orchid's original habitat, rainfall is abundant and the air is moist, with relative humidity above 80%; especially Cymbidium sinense grows beside streams, where mist is often everywhere and relative humidity is around 90%. One important reason why growing orchids in the north is difficult is dry air. In ordinary urban homes and on balconies, growing orchids is not easy to succeed at, and insufficient temperature is also a major factor. When air humidity is low, orchid leaves are rough and dull, lacking luster; when air humidity is suitable, the leaf surface is moist and green. Usually the humidity required during the orchid's growing period must not be lower than 70%, and in the winter dormant period it is about 50%; humidity at night should be somewhat higher than during the day. Humidity and ventilation are two relatively opposing factors: too much ventilation lowers humidity, and in northern winters and springs dry winds blow frequently and humidity cannot be maintained, which is unfavorable to orchid growth, so ventilation should be appropriately reduced.
Methods for regulating and raising 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 and then release it through the leaves at the surface. They can also retain surface water, which gradually transpires, increasing the content of water molecules in the air and thereby raising 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 space of the orchid-growing site or on the leaves. However, spraying or sprinkling water on the leaves should not be done at night; if you need to sprinkle water on the leaves in the evening, be sure that the leaf surface can dry again by nightfall. In southern China there are sometimes long spells of overcast rain, and especially during the plum rain season when humidity is excessive, doors, windows and covers should be opened for ventilation. Orchids like warmth and moisture, and when humidity is high and ventilation is good, orchids will grow robustly; but when the temperature is low and there is no ventilation, water vapor will condense into droplets, which is harmful to new shoots and easily triggers disease, so low temperature with high humidity should be avoided. In the seedling beds where we grow orchids in the ground over a large area, bricks are laid around the perimeter and moss is planted on top. Bricks and moss have a very strong capacity to absorb water and retain moisture, and this economical and convenient natural humidifying measure is very effective.
5. Watering. When watering, attention should be paid to water quantity, water quality, water temperature, watering time, watering method and other issues.
In the classification of xerophytes, hygrophytes and mesophytes, orchids belong to the mesophytes and do not need excessive water, so the potting soil should not be too wet. This is determined by the structural characteristics of orchid rhizomes. The pseudobulbs of orchids are plump, with a cuticle on the surface, while the epidermal cells are thickened to form stone cells, and the stem is filled with vascular bundles. The pseudobulbs can store nutrients and water and do not easily evaporate it. Orchid roots are mostly fleshy, with the outermost layer being velamen tissue, whose cells are elongated and polygonal. When the velamen tissue cells mature, the protoplasm disintegrates and the cell walls develop thickened striations. The function of the velamen tissue is to protect the cortex, absorb water, and reduce and protect against the loss of water from within the cortex. Therefore orchids should not be watered too frequently, and the potting soil should not be too wet, lest the roots rot. In addition, judging from the orchid's places of origin, orchids mostly grow on mountain slopes, on both sides of ridges, and in rock crevices. These places drain well and have no problem of accumulated dampness or standing water. It is precisely by adapting to such an environment that the orchid's rhizome structure is suited to storing and conserving water and nutrients.
Principles of watering orchids:
The following conditions must be relied upon:
(1) The type of orchid.
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 it need not be watered too much. In addition, those with thick cuticles on the leaves should be watered less; for example, the leaves of 'Tiegusu' have a thick cuticle and lose little water through evaporation, so watering must be strictly controlled.
(2) The orchid's growing season.
In spring the temperature gradually rises, and this is the season when new shoots sprout, so watering should be timely. Water once a day or every other day to keep the potting soil moist. A lack of water during this period delays flowering and makes the shoots weak. In summer the temperature is high and evaporation is great; this is the period of leaf expansion, root emergence and extension of roots and leaves, so water once every morning, and in the evening if the potting soil is dry, you may add some water to soak the potting soil and thoroughly moisten the leaves, lowering the temperature and reducing nutrient consumption to favor growth and development. Entering autumn, the temperature gradually drops and orchids grow slowly; observe the potting soil's moisture every day, watering when it is dry and leaving it when it is wet. In winter orchids enter dormancy. The potting soil should be somewhat dry, and watering should be reduced or omitted, but the potting soil must be watched to prevent it from losing so much water that it instead draws water out of the roots. At the turn of winter and spring, after Cymbidium goeringii has formed buds the flower buds begin to elongate, so the potting soil should also maintain a certain humidity. If the potting soil is too wet in winter, the water content of the orchid plant increases, which easily causes freezing damage.
(3) The orchid's growth condition.
If the orchid grows vigorously and has good roots, it can be watered more; otherwise reduce watering as appropriate, and for diseased plants water must be controlled even more. When orchids are sprouting and growing, water may be increased; after sprouting it can be gradually reduced. When the new shoots gradually mature, water should again be reduced somewhat; when flower buds appear, water slightly more; but during flowering, water should not be too much, in order to prolong the flowering period. After the flowers fade, watering should be stopped for several days so that the potting soil becomes slightly dry and the orchid rests a little, and then watering can resume.
(4) The condition of the pot and the plant.
That is, water according to the texture and size of the pot: water more for clay pots and large pots, and less for porcelain pots and glazed pots. Water more when there are many potted plants or when ground-planted orchids are densely set.
(5) The dryness or wetness of the potting soil.
The basis for watering, such as season, plant, weather, pot and soil quality, can all be reflected comprehensively in the degree of dryness or wetness of the potting soil, so the dryness or wetness of the potting soil is the direct and intuitive basis for watering.
It can be judged by observation and touch. If the potting soil becomes hard, its color becomes lighter, and the moss on the pot surface is dry and wilted, it indicates that the soil is dry. It should be watered at once. If the potting soil is dark in color, has moisture, 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 height of summer it is best around sunrise and around sunset; in early winter and early spring it can be done when the sun is at its zenith and the temperature has warmed slightly. During the period when they are brought indoors for the winter, watering must be done at noon on clear days. But care should be taken to avoid wetting the leaf surface or letting water seep into the leaf sheaths. Among the people there are some very valuable experiences with watering orchids; for example, for Cymbidium goeringii and Cymbidium faberi there is the experience that they should not be dry in autumn, not wet in winter, like moisture in spring, like slight dampness in summer and autumn, and in winter need moisture with some dryness. This shows that orchids have different water requirements at each stage of growth and development, and management should be adapted to local conditions and handled flexibly. Generally after the Beginning of Spring, the climate gradually warms, the flower buds swell, and the soil should be kept moist, spraying water once every 2-5 days. After Awakening of Insects, for flowerless Cymbidium goeringii and Cymbidium faberi grown in the open, wind and sun easily dry the water in the pots, so routine watering should be frequent, but the amount 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 somewhat drier, because after flowering most have a brief dormant period, grow slowly and lose less water through the leaves. From June, as the weather gradually heats up, the young shoots (that is, the young sprouts) grow faster, and at this time more attention should be paid to soil moisture, frequently sprinkling clear water on the orchid leaves and orchid benches to create a moist microclimate, which favors the young shoots' elongation and leafing. During the plum rain season, watering should be controlled to reduce the occurrence of disease; leaf-variegated types and some petal-type seedlings are even more prone to disease and should be watched even more. In the dog days the climate is hot, and besides strengthening shading, the soil moisture must also be carefully maintained, sprinkling clear water on the leaves and pot surface around sunrise every day. After White Dew it gradually turns cool in autumn, and with the moisture of night dew, the growth of new growth stalls, and the orchid buds break through the soil and grow slowly, so watering can be reduced; but when the potting soil is found to be dry, it must be watered until moist. In late autumn, the new growth has turned from fresh green and tender green to deeper and darker shades. When both the flower buds and their sheaths are visible, guard against prolonged rain and excessive moisture to reduce sheath rot (that is, rotting of the bud sheaths); seek shelter from rain and let them receive more sunlight.
(7) Water quality and water temperature for watering.
For watering orchids it is best to use stored 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 you have no choice but to use tap water, it should be stored in a reservoir for more than 24 hours, and exposure to sunlight is even better, so that after the disinfectant settles out or decomposes, the clear water on top can be taken to water the orchids. Besides this storage treatment, there is also an activation treatment: keeping fish, algae, chlorella, red floating algae and other aquatic organisms in the reservoir where tap water is stored, in order to improve water quality. But be careful whether the fish have diseases, to prevent contamination of the water quality. The temperature of the potting soil can directly affect the water-absorbing function of 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 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 physiological balance. So in summer, watering orchids should be done in the morning and evening, when the water temperature is close to the soil temperature. Reservoirs or water vats are best buried half in the soil, plus shaded, so that the water temperature does not get too high in summer.
(8) Watering methods.
Common orchid watering methods include pouring, spraying and soaking. Usually a watering can, ladle or hose is used to water; when pouring, pour slowly from the edge of the pot so that the water gradually soaks downward and toward the center, and never pour it suddenly into the center of the leaf cluster, nor let the water splash up the potting soil and dirty the leaves. Spraying should soak the whole pot, not just half of it, meaning water only on the surface while the lower layer gets none; if half-watering continues for a long time, the surface is wet while the interior is dry, so some orchid roots cannot absorb water for a long time and shrivel, while the upper orchid roots turn upward and grow, sprawling and coiling in the surface soil. To save trouble, many people connect a rubber hose directly to the tap and water the orchid pots with it, which is very harmful: first, the tap water has not been treated and the bleaching agent is harmful to orchids; second, the water temperature differs greatly from the soil temperature; 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 leaves; this method is often used during the orchid's growing season. Do not spray too much each time; the standard is that the leaf surface is wet without water running off. If too much water pours 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, with water droplets fine and even. The soaking method is also called seep-watering, that is, placing the bottom of the orchid pot into shallow water and letting 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, take the orchid pot out at once. This method keeps the orchid leaf surface clean. In dry seasons, the orchid pot can also be placed in a shallow tray, so that the pot absorbs the accumulated water in the tray and then soaks the potting soil, which can maintain relatively stable soil moisture. The disadvantage is that the drainage hole at the bottom of the pot is blocked by water, so air permeability is affected to some extent.
6. Light and sunshine. Light refers to the quality and quantity of sunlight, including wavelength, spectral composition and light intensity. Sunshine refers to the duration of sunlight; generally more than 14 hours of illumination 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.
The orchid's requirements for light:
There is a floral proverb: 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 needs, 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, disliking 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, fine in texture and lustrous; with too weak light, the leaf color is dark green but loses its luster. The effect of light on sprouting -- the strength of light has a direct influence 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 grow poorly. Therefore, starting some time before flower bud formation, appropriately increasing light can promote flower bud differentiation and achieve the goal of more flowers. 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 Ningbo in Zhejiang had a kind of snow orchid, produced on shaded north-facing slopes; if planted in a pot and exposed to a little sun, it turned green, and so it was regarded as rare and precious, yet today it is often encountered when collecting in the wild, and artificial cultivation can also obtain it. Some people use this to commit fraud, passing it off as a new variety, and the inexperienced are often deceived. If other conditions are the same, orchid pots placed in a stronger-light position bloom first; this is because accumulated illumination and accumulated temperature first reach a certain value. Some people have experimented and found that extending light duration to 14-16 hours can promote earlier flowering in 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 met to promote flowering. For orchids that bloom in summer, long days and short nights and high temperature are required to promote flowering. For orchids with flower buds, to promote earlier flowering, light and temperature can be appropriately increased. In a small room, a 100-watt bulb can raise the room temperature by 3°C-5°C and can promote earlier flowering. The relationship between light and leaf variegation -- leaf variegation is a cultivation technique in which lines or spots appear on the leaves. Leaf variegation is related to light. Changes in light can be used to promote changes in leaf variegation. 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, set the orchid pot in the sun, insert a thermometer in 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 into the sun again. Repeat this over the long term. One shade and one sun, one cold and one hot, favor 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 a recessive factor for leaf variegation within the orchid leaves; the change in sunlight merely promotes its manifestation.
The basis and methods for regulating orchid light:
A liking for half-shade, half-sun light is common to most Cymbidium species, but there are also differences among species. Species that bloom in spring, such as Cymbidium goeringii, Cymbidium goeringii var. longibracteatum and Cymbidium faberi, need relatively weaker light, and the shading degree should be controlled at 70%-80%. Species that bloom in summer and autumn, such as 'Xiahui' and 'Qiusu', need somewhat stronger light, and their shading degree should be controlled at 60%-70%; Cymbidium sinense needs about 85%. The light duration and intensity of spring, summer, autumn and winter are all different and should be treated separately, adjusting the shading degree well. Within a single day, morning and evening sunlight can be allowed to shine on them, but 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 a summer rainstorm, or when it first clears after long rain, orchid pots must absolutely not be exposed to the sun; the predecessors' experience: if sunned right after rain, the water in the pot is hot, which scalds the leaves and injures the roots. Although orchids are relatively shade-tolerant, they also have phototropism, and in the same cultivation site the flowers and leaves on the sunny side are always 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 turned and adjusted at intervals. If it is for special needs of shaping or composition, in order to express a particular poetic and pictorial mood, 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 -- build greenhouses, orchid pavilions, waterside pavilions and orchid corridors to place orchids, using 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 curtains or shade netting can be hung for regulation. For potted orchids kept on balconies, light is regulated by carrying them in and out, and although this is hard and tiring, it also cultivates enjoyment, combining flower growing with fitness, with the joy contained within. Building frames -- shade frames can be made of bamboo, wood, angle steel and so on, covered with bamboo curtains, plastic film, shade netting and the like. Our method of regulating light intensity is to set up bamboo frames in the orchid nursery and install on them a double layer of shade netting 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 double layers, in spring and autumn use a single layer; on clear days at noon in summer and autumn use double layers, on cloudy and rainy days a single layer. In winter it depends on the situation: on clear days let down the lower layer, on cloudy days roll up the lower layer, because in winter the light change inside the plastic shed must not be too great; if too great, the temperature and humidity also change accordingly, which is unfavorable for orchid winter dormancy. In addition, before the orchid flower buds are ready to open, they must have moderate diffused sunlight, otherwise the flower color is dull and does not show its beauty. Building trellises -- on the orchid cultivation site, build bamboo frames, wooden frames or reinforced concrete frames and let vines such as grape, honeysuckle, morning glory, Chinese trumpet creeper and cypress vine climb and spread over them, which both shades and is beautiful, practical and economical. Deciduous vines shade in summer and let light through in winter, which is a natural regulation. Planting trees -- around the orchid nursery, plant a combination of evergreen trees, deciduous trees and bamboos of different heights to regulate light intensity.7. Fertilizing. Orchid roots have no fibrous roots, and within the roots there are symbiotic bacteria.
The root bacteria absorb mineral nutrients from outside and supply them to the orchid, while the orchid root cells provide water and organic nutrients to the root bacteria, 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 robust orchid growth. Previously some people thought that since orchids grow in the mountains and are by nature elegant and pure, clear water and fresh air are enough to sustain them. Others loved orchids too deeply and were too impatient, often applying strong, highly concentrated heavy fertilizer, producing results contrary to their wishes. Therefore we must seriously explore scientific and rational fertilization.
(1) Types of fertilizer.
Fertilizers can be distinguished by their effective components, their nature and their method of use. By effective components, they are mainly nitrogen, phosphorus and potassium fertilizers. Nitrogen is a major component of cell nuclei and proteins, and 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, *manure and urine, urea, green manure, ammonium sulfate and ammonium nitrate. Phosphorus is also a major component of cell nuclei and directly affects cell division, chlorophyll formation and protein synthesis and transformation within plant cells; it can promote flower bud differentiation and growth and bring about larger flowers, more vivid color and stronger fragrance. Commonly used phosphorus fertilizers include superphosphate, potassium dihydrogen phosphate, phosphate rock powder, bone meal and rice-washing water. Potassium directly participates in photosynthesis, can keep 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; it can also increase the fragrance of the flowers. Commonly used potassium fertilizers include plant ash and potassium sulfate; potassium dihydrogen phosphate is also a fertilizer containing relatively much 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 requirements for nitrogen, phosphorus and potassium are relatively large and must be met through fertilizing, repotting and changing the 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, able to continuously decompose long-lasting nutrients for the orchid to absorb. Inorganic fertilizer, also called chemical fertilizer, has a high nutrient content, is clean and odorless, and can be diluted and used immediately without fermentation; it is convenient and quick-acting, but its effect does not last long, and long-term use can degrade soil structure. Generally orchid growers oppose the use of chemical fertilizer. 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 top dressing. Base fertilizer is the fertilizer added when preparing the culture soil or before planting, such as leaf mold, green grass compost and chaff soil, which are both the substrate for cultivating orchids and base fertilizer. Silkworm droppings, *manure, cow dung, bone meal, hair and cake fertilizer can all be added as base fertilizer at the bottom of the pot or turned under the soil as base fertilizer, but chicken manure and human feces should be avoided.
(2) Top dressing is fertilizer applied during the growing season after the orchids have been planted.
Generally orchids are only repotted and given fresh soil 2-3 years after planting, and nutrients must be supplemented in the meantime, so top dressing should be applied.
Time of fertilizing:
During the spring and summer growing period of orchids, to make them grow robustly and vigorously, more nitrogen fertilizer can be applied. If it is a leaf-variegated variety, then apply less nitrogen fertilizer or none, because a dark green leaf color will affect the appreciation of the leaf variegation. 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 fertilization is too frequent in summer, it easily forces autumn shoots, and the plants grown thereafter 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. Apply fertilizer 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. Before the orchid's new shoots have grown to half maturity from the pseudobulb, and before and after the leaf buds emerge from the soil and during their elongation period, this is the orchid's vegetative growth stage, and slightly more nitrogen fertilizer should be applied, with less phosphorus and potassium fertilizer. After vegetative growth comes reproductive growth; the nutrients made by photosynthesis are stored in the pseudobulbs and leaves for flowering or new shoot growth. At this time more phosphorus and potassium fertilizer is needed, and applying some phosphorus and potassium fertilizer can promote the pseudobulbs to become plump and mature and to produce shoots and flowers. If the orchid grass has a pale, yellowish leaf color and a weak plant, it is mostly caused by fertilizer deficiency and should be top-dressed in time. But sometimes leaves also turn yellow because sunlight is too strong. Diseased plants should not be fertilized; wait until the disease has been cured and they have recovered before fertilizing. Robust orchid seedlings given more fertilizer can be helped to grow.
Ancient orchid growers had the 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 heavy fertilizer, for it cannot absorb it and it will be harmful. For an orchid that is often fertilized, it also cannot go for a long time without fertilizer. In short, uneven fat and thin is of no benefit to orchids. Usually Cymbidium goeringii, Cymbidium faberi and Cymbidium ensifolium begin to be fertilized in early May. In summer during the dog days, and from December to early February of the following year, no fertilizer is applied. From May, apply dilute fertilizer once every 2-3 weeks until the end of September. In early September apply dilute fertilizer once to Cymbidium goeringii, and in late September fertilize Cymbidium ensifolium once. After each fertilization, clear water must be added the next morning, which facilitates absorption by the orchid and also prevents harm to orchid roots from improper concentration. Generally, do not fertilize around the time of flowering.
(3) Fertilizing methods.
Fertilization must mainly use organic fertilizer, which can make the soil loose and well structured, favoring orchid growth. Also, apply thin fertilizer frequently; that is, the predecessors' experience that it is better to be frequent and dilute, and one must absolutely avoid sudden and heavy applications, which is what people today mean by small amounts and many meals. When applying, dilute the water-and-fertilizer appropriately, then pour it into the root zone with a watering can, without contaminating 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‰ potassium dihydrogen phosphate can be used as top dressing 2-3 times.
8. Ventilation.
Ventilation is also very important in orchid cultivation and management, yet it is often overlooked by people. 146 'Zhuhongxinsu' (Beijing). Good ventilation, continuously supplying orchids with plenty of fresh air, can promote photosynthesis, increase nutrient production, promote metabolism and make orchids luxuriant. Ventilation in orchid rooms and shade sheds can regulate their temperature and humidity, making them favorable for orchid growth, and can also reduce the occurrence of pests and diseases. Orchid brown spot and southern blight mostly occur in poorly ventilated environments. The orchid-growing site must be open, the terrain should be slightly high, the flower benches should not be too low, and attention should always be paid to ventilation. Orchids like gentle and soft breezes, not sharp winds, and overly cold or strong winds should be avoided by whatever means. Orchid pots should be placed sparsely rather than densely, and enough distance should be kept between pots to prevent leaves from rubbing against each other and being damaged by wind. If the site is small, the flower benches can be built in stepped form, which favors ventilation and is also convenient for management and appreciation. Each orchid pot should not contain too many or too densely packed plants. If the plants multiply too densely, they should be repotted and divided in time. Frequently clear weeds, diseased leaves and fallen tree leaves and other debris from the orchid pots to favor ventilation within the pots. Routine work throughout the year for ground-planted orchids: In spring, around Qingming, remove the plastic film from the shed, then water thoroughly once; several days later apply once a 15-20 times diluted duck-feather water or fertilizer water fermented from 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, and 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 urge early maturity. Generally, potted orchids should follow the golden rules of orchid growing: do not take them out in spring, do not sun them in summer, do not let them dry in autumn, do not let them stay wet in winter. But ground-planted orchids are not entirely like this; in autumn they should be dry rather than wet. The reason is: although the air is dry in autumn, ground vapor still rises in the soil, so there is no severe water shortage; moreover, drought can temper the orchid's cold resistance and prepare it for overwintering. Autumn tempering can urge nutrients to gather in the pseudobulbs, raise the protoplasm concentration of the pseudobulbs, lower the freezing point, and prevent freezing damage. If in autumn the orchid seedlings grow vigorously and then a cold current arrives with a sudden drop in temperature, they will inevitably suffer freezing damage. Ground-planted orchids cannot be moved indoors before severe winter arrives, so only through autumn tempering can they survive. November is a relatively busy season in the orchid nursery, and the main work is to prepare for the orchids' overwintering. First remove the upper layer of shade netting, then install the plastic shed; the two ends of the shed are not closed at first, and are closed only when the temperature drops noticeably, opening for ventilation at noon on clear days. This month spray once with 1:1 Bordeaux mixture. Entering the severe winter season, first, do not water easily; second, moderately increase light. Moderate means that in winter some clear days have relatively high temperatures, especially with the warming-winter phenomenon in recent years; at such times the lower layer of shade netting should be let down so that the temperature inside the shed does not suddenly rise or fall. If the shade netting is not let down and the temperature inside the shed reaches 18°C-22°C for several consecutive days, some new shoots will start to sprout, and once a cold current arrives and the temperature drops suddenly, they will certainly be frostbitten. Therefore, in winter a dormant environment must be created for orchids, and dormancy must not be broken easily. In early spring, cold and warm air masses move frequently over the land, so management must be even more careful; otherwise orchid seedlings that have consumed nutrients through the winter are very likely to turn yellow. Light should be gradually and moderately increased, and the plastic film must not be removed too early; only after the weather stabilizes and clears in early April can it be removed.
1. Potting soil requirements: A neutral to slightly acidic soil containing plenty 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 under moist-leaved forests in mountainous areas are used to cultivate orchids.
2. Placement site: In spring, summer and autumn, orchids can be grown outdoors and on balconies; choose a place with good ventilation, moist air and no environmental pollution. Being near a pond or riverside is of course good, but at least there should be tall trees or bamboo groves and shade netting to reduce sunlight and lower the temperature. Orchid pots are best placed on wooden frames (or steel frames); if placed on the ground, bricks should be used underneath. In home balconies, a small galvanized-iron water tank can also be used to store water, with bricks on top for growing, to increase humidity.
3. Appropriate shading: Most orchids belong to semi-shade plants, and most species fear direct sunlight and need appropriate shading. In early to mid-April, orchid nets can be removed and windows opened, letting them receive more sunlight to promote growth. In May, apart from the midday sun, they can receive 6 hours of light; from June, shade all day long; 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. Rational fertilization: Orchids are by nature "vegetarian," and fertilizing should depend on the chosen potting soil and growth condition. Those growing luxuriantly and free of disease can be fertilized, while those growing poorly should not be fertilized or only lightly fertilized. Newly potted orchids whose roots have not fully developed must wait 1-2 years before fertilizing. Generally in June-July, when the orchid leaf buds have elongated to about 1.5 cm, apply a fully decomposed liquid fertilizer once every three weeks (the concentration should be dilute, about 10%). Avoid chemical fertilizer; in high-temperature seasons it is not suitable to fertilize. In August-September apply diluted liquid fertilizer once every two to three weeks. Each fertilization of orchids should be done in the evening, and clear 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 must 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 dryness or wetness of the potting soil and the growth condition of the orchid grass. Water more for large leaves and less for fine leaves. In April-May, when new shoots have not yet emerged from the soil, the potting soil should be somewhat dry, because if too wet the new shoots easily rot; June-September is the growth period of new orchid shoots, and the amount of water should be increased, watering once every morning on clear days, and absolutely not watering under the fierce midday sun. In autumn appropriately reduce the amount of water, and leaf-surface misting can be used, keeping the potting soil moist; in winter the amount of water should be controlled even more, keeping it at "eighty percent dry, twenty percent wet" as appropriate.
6. Evening misting: Orchids originally grow in a humid environment, so in dry seasons, besides 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) of the potted orchids; "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 easily rot. In rainy seasons, a small amount of plant ash can be appropriately scattered.
8. Pruning and flower removal: During orchid cultivation, withered yellow broken leaves and diseased leaves should often be cut away. This favors 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 opening, and precious orchids should be removed after 7 days, so that the spring leaf buds grow sturdily and produce better growth and better flowers the following year. For summer orchids, when the last flower on the inflorescence has been open for one week, cut it off 3 cm above the pot surface.
9. Cold protection and warmth: Because orchid varieties differ, their places of origin differ, and their cold resistance also differs, 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, so they should be brought indoors (or windows closed and nets drawn) when the temperature is 5°C, and placed in a south-facing sunny spot as far as possible. Spring and summer orchids have strong cold resistance, so they can wait until 0°C before being brought indoors and placed on the northeast side. Around noon on clear, windless days, windows should be opened on the south or southeast side and nets pulled back for ventilation. Autumn orchids should not have windows opened on clear days at 1-2°C. Of course, if there is a greenhouse, electric light heating can be used.
10. Disease and pest control: Potting soil should generally be sterilized (sun exposure also works) 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 called "orchid lice") occur most; during the hatching period, use a 1000-fold solution of 1% omethoate and 25% phosmet emulsifiable concentrate, spraying once a week. To treat the symptoms one must treat the root cause: pots should be spaced appropriately, placed high and low, with increased air circulation and ventilation, so as 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 growing, and our predecessors accumulated rich experience in orchid cultivation for us. We should thoroughly understand the experience of our predecessors, absorb its essence, and deeply recognize that: the cultivation environment, growing medium, watering, fertilizing, 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 airy conditions. As long as the growth rules of orchids are grasped and growing environment 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 growing medium. According to cultivation experience in various places, as long as it is slightly acidic, any growing medium (including soilless culture) can grow orchids well; the problem is that different growing media should be managed by different methods. For flower pots, clay pots or Yixing clay pots are best, because orchids are aerial-root plants and pots that breathe are very favorable for orchid growth.
3. Rational watering is the key to growing orchids well. The water for watering orchids must be clean and slightly acidic, and water containing disease-causing organisms must never be used. The watering method should differ according to the plant. Loose mountain soil holds sufficient water, and granular soil plus pumice and volcanic rock also absorbs water relatively fully, but does not accumulate water. After different growing media have been given one thorough watering, when the pot surface is seen to be dry, the growing medium about one centimeter deep turns white. To raise the air temperature, the pot surface can be misted, increasing the moisture of the upper potting medium so that the orchid grass and pseudobulbs maintain a certain moisture; when the whole pot has not dried through from top to bottom, water heavily again, thoroughly.
4. Fertilizing: On the basis of mastering watering well, in order to promote better growth of the orchid grass, fertilizing becomes even more important. Organic fertilizer, that is, farmyard manure, should be dilute and can be applied once every ten or more days; other inorganic fertilizers (chemical fertilizers) should be used according to the instructions. During the orchid growing period, foliar fertilizer can be applied as a top dressing outside the roots. Base fertilizer is also very important; when repotting and changing soil, if the fertilizer does not touch the orchid roots, an appropriate amount of base fertilizer can be added. Too much fertilizer easily burns orchid roots and produces black spots. If fertilizing is done properly, it can produce sturdy seedlings and good flowers. The general requirement for fertilizing orchids is small amount, clear, dilute and light, truly achieving thin fertilizer applied frequently.
5. Pest and disease control: Insect pests are easy to prevent, but fungal diseases are hard to cure. If scale insects and other pests are found on orchid grass, spray with omethoate or fenvalerate according to the instructions, preferably mixed, 2-4 times a year. General fungal diseases such as black spot can also be treated; use fungicides such as copper hydroxide, thiophanate-methyl and chlorothalonil according to the instructions, spraying alternately for treatment and prevention at regular intervals of 15-20 days during the growing period. If "Bailasi" soft rot (rot coccus disease) is found, it is a terminal disease among orchids that cannot be cured at all; once found, remove it promptly. Therefore, when buying orchid grass, be sure to pay attention and never buy low-priced diseased grass and bring it home, thereby affecting other precious orchid grass.
Different orchid species have different temperature requirements. For Chinese orchids, the most suitable temperature for vegetative growth is 20-30 degrees, the adaptable temperature is 5-35 degrees, and the temperature during the reproductive period is generally between 5-15 degrees. Night is 3-5 degrees lower than day. When the summer temperature is above 30 degrees, the higher the temperature, the more orchid growth is hindered. But Chinese orchids under ventilated conditions are unharmed by short-term temperatures as high as 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, daytime temperatures can reach about 32 degrees, while at night it is cooler, with temperatures generally not exceeding 20 degrees, and in winter the temperature does not drop below 10 degrees. Cymbidium kanran and Cymbidium ensifolium originally grow in mountain forests transitional to the subtropics. Cymbidium goeringii and Cymbidium faberi mostly grow in temperate mountain forests; in temperate regions, summer temperatures reach as high as about 38 degrees, but in shaded mountain forests daytime temperatures do not exceed 30 degrees, and at night are about 18 degrees. In winter, under short-term snow cover, the surface temperature still exceeds 5 degrees, with no effect on flowering. Indoors they can also overwinter at about 0 degrees. The suitable growth temperature for Cymbidium goeringii var. longibracteatum is 18-28°C; in summer it does not exceed 35°C, and in winter it does not drop below minus 2°C; the reproductive growth temperature is 8-18°C. The temperature requirements for Cymbidium tortisepalum are generally that in winter it does not drop below -12°C; in the spring and autumn reproductive period the temperature should not be below 12°C; in the summer growing period, temperatures mostly between 15°C-32°C are appropriate, and above 35°C is the critical line for growth; beyond this limit, growth stops again.
The driving force of orchid life -- light
"All things grow by the sun" - this saying concisely sums up the enormous role of light in the growth, development and continuation of generations of living things, especially plants. The orchid itself relies on the photosynthesis of its green leaves to obtain energy to maintain and continue its life and reproduce; sunlight is the driving force of the orchid's life. But for orchids, which require a semi-shaded, semi-sunny habit, excessively strong light can also harm their growth. The light suitable for orchids must be regulated and controlled according to the temperature, humidity and the growth habits formed under the ecological environment of various orchids in different seasons, so as to satisfy and benefit the survival and growth of orchids. Below, I will offer some immature views on the close relationship between light and orchids, to discuss with fellow orchid growers, which may be of some use for growing orchids well:
Let us explore this from five aspects:
1. The relationship between light and orchid growth.
2. The effects of light on orchid leaves, shoots and flowers:
3. The role of light in fertilizing and sterilizing orchids.
4. The light intensity for orchids.
5. Artificial regulation of light.
1. The relationship between light and orchid growth.
Suitable light can promote the normal growth of orchids: the growth of orchids relies on the photosynthesis of green leaves to obtain energy to maintain and continue life. 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; photosynthetic intensity is directly proportional to light intensity. That is, when light intensity doubles or halves, photosynthetic intensity also doubles or halves. Through the chemical action of chlorophyll in orchid leaves, light absorbs carbon dioxide and releases oxygen to increase the nutrients the orchid body needs. At night, the pseudobulbs and roots carry out digestion and decomposition, converting carbon dioxide into sugar, then forming 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, a maximum temperature and a minimum temperature, also called the critical points of photosynthesis. Too much and too strong sunlight, exceeding the critical point, will cause leaves to become dwarfed, yellowed, or even 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 equally 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 the 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, with population development controlled, to ensure the plants have enough light; if natural light is insufficient, artificial light should be added. Shade plants should be moderately shaded on the premise of satisfying their photosynthetic intensity as much as possible. Giving orchids 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 rays. The leaves of orchids respond only to red, orange, yellow and blue-violet series of light. 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 not entirely the same either. 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, manifested in plants as thickening; far-infrared light irradiation is beneficial to plant cell elongation, manifested in plants as growing taller; ultraviolet light irradiation is beneficial to shortening the nodes of orchids, manifested in plants as dwarfing. Therefore, when supplementing light for orchids, different light qualities should be set according to the specific growth conditions and requirements of 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 light portion of xenon lamps is similar 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 supplementary lighting for Chinese cymbidium cultivation should use more red light. Of course, if conditions permit, choosing plant lights specially designed for orchid supplementary lighting is even better.
In short, according to the type of photosynthetic products needed as described above, one should consider comprehensively, make up for deficiencies, and choose a suitable light source to promote the normal growth of orchids.
2. The effects of light on orchid leaves, shoots and flowers:
1. The effect of light on orchid leaves.
① Orchid leaves under different light: Orchids have long grown in mountain forests, developing a semi-shaded, semi-sunny habit; they like diffused light and dislike direct strong light. When light is too strong, orchid leaves tend to be shorter, thicker and stiffer, with a rough 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 the green. Too strong or too weak light will both affect the perfect growth of orchids.
② Changes in light can promote the appearance of leaf variegation. Plants with the potential for varied variegation can receive a longer period of light. For variegated-leaf orchids, sunlight from 6 a.m. to 9 a.m. is best. Someone did an experiment: before 9 o'clock in summer and before 10 o'clock in winter, place the orchid pot under the sun, insert a thermometer into the pot, and when it is sunned to 30°C move it into the shade. When the temperature drops to 25°C, move it out into the sunlight again. Repeat this over the long term. One shade and one sun, one cold and one hot, is conducive to the appearance of variable factors within the leaves, and over the years may produce variegated leaves. But this must be premised on the existence of recessive variegation factors within the orchid leaves; changes in sunlight merely promote their appearance, and there is no inevitable connection. Cells that have become white-spotted are the decisive factor and play the decisive role in changes in orchid leaf variegation.
2. The effect of light on sprouting. Light can increase the sprouting rate of orchids. The sprouting of orchids cannot rely solely on water and fertilizer management; appropriately increasing light is very key. 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 Orchids planted shallowly sprout more. Orchid growers generally believe that for orchids, "deep planting is not as good as shallow planting." This is because when orchids are planted deep, the pseudobulbs are buried deep and receive little light. Under the same fertilizer, water and management conditions, deeply buried pseudobulbs are small and sprout less in spring. When planted shallowly (with half the pseudobulb exposed outside the soil), the pseudobulbs are large and sprout more in spring. This is closely related to the spectrum and the length of light time. It also demonstrates the reason why 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 of emergence and the growth condition. Orchids with sufficient light produce more nutrients through photosynthesis, have more flower bud differentiation, bloom more, have deeper flower colors, and have large, good flower shapes. Conversely, orchids under too weak light, although the plants grow lushly, do not produce enough nutrients, and grow more leaf buds and fewer flower buds. Even if they bloom, the flower color is pale, the flower shape is poorer, and the growth condition is poor. Therefore, from a period before flower bud formation begins, appropriately increasing light 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 primal light. Violet light and ultraviolet light in light are the main light energy that forms orchid pigments. Therefore, sunlight has a direct effect on the colored flowers of orchids. Strong light makes flower colors deeper and more vivid; excessively weak light makes flower colors extremely pale. For example, to make the flower color of red-flowered lines beautiful, sunlight can be slightly strengthened; to make blue-flowered lines 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-shaped flowers should be exposed to more sun to thicken the petals. When growing colored flowers, attention to and control of light during cultivation can make the flower color more beautiful. Green and white flowers should reduce light; red, yellow, pink and purple flowers need increased light. For example, if Chunlan blooms in shade, the flower quality and color are better than when blooming in sun (except for colored flowers), and the flower stalk is also longer. For Huilan and Jianlan, stronger light is beneficial to flowering, producing larger flowers with good color and fragrance. Therefore, controlling and regulating reasonable light is a cultivation technique that must be mastered to fully display the best flower color.
② The effect of light on orchid opening.
For orchids with flower buds, to promote early or delayed flowering, this can be achieved by regulating the length of light time. Appropriately extend light and increase temperature. For example, in a small room, using a 100-watt bulb or infrared lamp 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 also delay flowering. For orchids that have already formed flower buds, appropriately extending sunlight 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 make them bloom earlier. Conversely, reducing light in a low-temperature environment can delay the flowering period, because raising or lowering the temperature can accelerate or slow the physiological activities within the plant. Using this biological characteristic, someone experimented: extending the light time to 14-16 hours can promote medium-sized plants and small seedlings to bloom earlier; but for mature orchid plants, a light time of no more than 8 hours is enough to promote flowering. Appropriately adjusting light intensity can make orchids bloom at the right time, especially for species that bloom in spring. Generally, flower buds have already formed from July to September of the previous year. After they pass through the dormancy stage, appropriately increasing light and raising temperature can make them bloom early, catching up with the Spring Festival holiday. Conversely, appropriately reducing light and lowering temperature can also delay flowering, to coincide with orchid shows. In short, regulating light intensity can make orchids bloom at the right time.
3. The role of light in fertilizing and sterilizing orchids.
1. The relationship between light and fertilization. Generally, for various orchids in different seasons and at various growth stages, how to shade and supplement light so that orchids receive suitable light intensity is of concern to everyone. However, in the process of orchid cultivation, how to correctly handle the relationship between fertilization and light may not necessarily be taken seriously, yet this is equally very important for the vegetative growth of orchids. The strength or weakness of light will lead to the strength or weakness of assimilation. If light is too weak, the assimilation of leaves is also insufficient. This leads to poor digestion of nitrogen fertilizer during the day, less accumulation of sugars and starch, and therefore less decline at night. Over time, the leaves will be very long while the roots are very short. If light is too strong, the assimilation of leaves is also too strong. Orchid respiration increases, consuming excessive nitrogen fertilizer, causing leaves to become short, small and yellowed. At the same time, abundant sugars and amino acids cause excessive growth of pseudobulbs and roots. The causes of these two adverse growth conditions may be many-sided, and light is not the only factor (for example, long-term dryness of the orchid pot, too much stem fertilizer, high-carbon growth, small day-night temperature difference, nitrogen deficiency and so on can also produce these problems.) Failure to correctly handle the relationship between fertilization and light is also one of the important reasons, and must be noted. The cultivation measures when encountering such situations are: when orchids show a state of "long leaves and short roots," the 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 phenomenon of "small leaves and strong roots," light should be reduced, and sufficient inorganic nitrogen should be continuously supplied. This can both lower the sugar content and promote protein synthesis, and the new growth will then return to normal.
Practice has proved 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 the morning of a fine day. When applying chemical fertilizer, the light intensity selected should be relatively higher; when applying organic fertilizer, it should be relatively lower.
2. Sunlight is a good weapon for sterilizing orchids and preventing disease. Light can not only raise temperature, but the ultraviolet rays in the spectrum can kill and prevent the breeding of fungi, pathogenic bacteria and viruses. Pathogenic bacteria generally find it very difficult to survive under blazing sun exposure. Therefore, exposure to the sun can sterilize and disinfect pots and potting media. But for the sterilization and disinfection of orchids, the use of sunlight must be timed. For example, sun orchids in winter, letting the whole orchid plant bathe in ample sunlight; in summer, avoid the blazing sun at noon and in the west-facing afternoon. Light can also close the stomata of orchid leaves, blocking pathogenic fungi that easily invade through the stomata. We have found that orchid plants with good light have strong disease resistance, while orchid plants with poor light, because their stomata are often open, are prone to infection by invading pathogens, and orchid plants with insufficient light are prone to pests and diseases. Using sunlight for sterilization and disinfection has long 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, concentrations of carbon dioxide and oxygen, wind speed, temperature, water supply, inorganic nutrients, and pollutants in the atmosphere and soil, and so on. In addition, photosynthesis is also affected by the plant's own internal factors, such as chlorophyll content, degree of stomatal opening, and the physiological state and structure of the leaves themselves. By improving the above internal and external factors, the goal of raising the efficiency of plant photosynthesis can be achieved. This promotes the healthy development, growth and flowering of orchids. In summary, according to the growth habits of orchids, giving appropriate light can improve fertilizer efficiency, enhance disease resistance, and benefit the healthy growth of orchids. For this reason, for orchid plants that are weak, do not bloom, and are prone to pests and diseases, light must be strengthened.
4. The light intensity for orchids.
1. Orchids grow in mountain forests, and the ecological environment has shaped their need for semi-shaded, semi-sunny light conditions. There is a folk flower saying: "Shade for camellias, sun for peonies, half shade and half sun for four-season orchids." This shows that orchids have a semi-shaded, semi-sunny light habit, and the growth of all kinds 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, the light requirements of various orchids differ in strength and weakness. Generally speaking, Huilan and Jianlan need more light for growth and can be shaded less. But in the vigorous growing summer and early autumn, strong direct light will still scorch some leaves, causing the leaves to turn brown, or even scorch and wither. At this time, shading is necessary, blocking 70%-80% of sunlight. Hanlan and Molan relatively need a bit less light, and in summer should block 80%-85% of sunlight. For newly potted plants, diseased and weak seedlings, old plants, especially delicate plants, and plants that have not been hardened and have long been kept in semi-shade and semi-sun, shading must be given during the growing period. For marginal-variegated plants, striped plants, crystal plants, if they are transparent bodies and so on, 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 the same light requirements. For example, variegated plants, colored flowers, and strong or 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 for various orchids.
3. Orchids can roughly be divided into three categories: sun-loving, semi-shade-loving and shade-loving, 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 Jianlan and summer Hanlan 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 Chunlan, Chunjian, Huilan and Molan that bloom in late autumn and winter.
4. Reference values for the optimal sunlight intensity of various orchids (unit: LUX)
Orchid species Sunlight range Optimal light intensity Light intensity for variegated plants
Four-season orchid 10000-14000 **** 10000
Huilan 9000-13000 11000 9000
Chunlan 8000-**** 10000 8000
Chunjian 8000-**** 10000 8000
Lianbanlan 8000-**** 10000 8000
Hanlan 8000-**** 10000 8000
Molan 4000-****5000 4000
"Fairburn and Pringle pointed 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, length of sunshine, nutritional conditions, humidity, and the day-night temperature difference, and so on." -- Excerpted from Wu Yingxiang's "Chinese Orchids." Therefore, the sunlight intensities above are only reference values.
5. The light intensity for orchids changes with the seasons: In winter and spring, orchids should see more sunlight and basically can go without shading. In summer and autumn, sunlight before 8-9 a.m. should be fully enjoyed, while the west-facing afternoon sun must be avoided, otherwise orchids are prone to disease. Sunlight and temperature have a great influence on orchid reproduction. For example, if there is no sunlight for a long time in winter and the temperature is relatively low, this will affect the formation of winter buds, leading to fewer and poorer-quality seedlings in spring, affecting the whole year's growth rate.
6. Orchids like 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, orchids should fully receive light. Generally speaking: at 20-25°C, under direct sunlight, the chemical reaction between chlorophyll in orchid leaves and light is very fast, and the plants grow vigorously. Above 30°C, the chlorophyll in the leaves automatically decreases, the leaf color becomes lighter, 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 long, it starts from the leaf tips first, and the whole plant gradually withers and dies, especially old plants, which first turn yellow and then scorch. Therefore, the length of time orchids receive light changes with high and low temperatures, in an inversely proportional relationship.
7. Orchids like morning sunlight. When the morning sun first rises, the sunlight angle is low, and the area of the orchid receiving light is large. Also, because the morning sunlight is blocked by morning mist, the light is relatively soft, and direct light will not scorch orchid leaves. After orchids accumulate nutrients at night, their photosynthetic capacity is strongest in the morning.
5. Artificial regulation of light.
Light that is too strong or too weak is unfavorable to the growth of orchids, and the light for orchids varies greatly with season, weather, region, environment and so on. If because of this the light is too strong, artificial shading must be adopted, the degree of shade adjusted, and the light for orchids reduced. If because of this the light is insufficient and affects the healthy growth of orchids, artificial lighting must also be adopted to moderately supplement light for orchids, letting them have relatively abundant light of sufficient duration. In short, to give orchids appropriate light, it must be regulated artificially.
1. The basis for regulating orchid light:
① Regulate the appropriate light for various orchids according to differences in their light requirements. Different orchid varieties differ in photosynthesis and optimal temperature. For example, different orchid species and variegation types differ at different times and in different regions. On blazing sunny days in midsummer and golden autumn, regarding shading requirements, the shade level for Jianlan is 60%-70%; Chunlan and Huilan require 70%-80% shade in summer, while Molan needs about 80-85%. Ordinary variegated-leaf orchids can have about 80%, while high-grade variegated-leaf orchids, crystal orchids and patterned orchids should have about 90%. Flower-type orchids and ordinary variegated-leaf orchids can have full light before 9 a.m. and after 4 p.m. on clear days; high-grade variegated-leaf orchids, crystal orchids and patterned orchids should be half-shaded. In high-temperature "furnace" regions, the shading density should be correspondingly increased by more than 5%. In winter and spring, appropriately increasing the light amount by 20% is more beneficial to orchid growth.
② Adjust the shade level according to the light time 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 deep color, and cause the leaves at the base of the plant to bend downward or outward. Especially during the leaf-emerging period, it makes the leaves grow excessively. Conversely, too much light will make the leaves yellow, or the chlorophyll will be destroyed causing cell death, and too much light makes the leaves shorter and thicker and causes them to open prematurely or bend outward. Therefore, except in early winter and midsummer, move orchids outside in the morning until 9-10 o'clock, so they get sufficient light. As the angle at which sunlight strikes the earth shifts, light time and light intensity and so on will all change. In the winter and spring seasons with short and weak light, except that high-grade variegated-leaf orchids, crystal orchids and patterned orchids need 60%-70% shading, all other orchids can have full light, or be half-shaded daily from 10 to 14 o'clock on clear days. In the summer and autumn seasons with long and strong light, the shading time and density for orchids must also be adjusted accordingly.
③ According to changes in weather. With ever-changing weather such as clear, partly cloudy, cloudy, overcast, and rainy or snowy days, light also changes frequently and correspondingly. Therefore, the shading degree must be appropriately adjusted with weather changes and the strength of light. In particular, high-grade variegated-leaf orchids, crystal orchids and patterned 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 the strength of light, the sprouting rate and flowering rate of orchid plants will naturally not be as good as with timely adjustment.
④ According to the changes in sunlight within a day - clear turning cloudy, cloudy turning clear, clear turning rainy, clearing after rain and so on - morning and evening sunlight can be allowed to shine freely, but the blazing noon sun must be blocked and regulated, and on cloudy days the shade level should be reduced. It is worth noting that after a summer rainstorm, or when it first clears after a 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, which scalds the leaves and injures the roots."
⑤ Regulate specifically according to differences in climate and light intensity in different regions. China is vast, and the cold and heat of the climate and the intensity of light are not uniform and differ greatly. However, the standards and requirements for strong, weak and appropriate light for orchid growth are still unified, and specific regulation can be carried out according to the local climate.
⑥ Regulate according to the level of temperature. The photosynthesis of orchids is closely related to temperature. Generally speaking, Chinese cymbidiums carry out normal photosynthesis at 5-36°C; the optimal temperature is 18-28°C; when the temperature is as low as 0°C or as high as 40°C, these are the limits, and orchid photosynthesis is inhibited. Starting from the low-temperature limit, photosynthesis strengthens as temperature rises. Beyond the optimal point, photosynthesis declines; above 36°C photosynthesis is very weak, and when it reaches the 40°C limit, photosynthesis also stops. When the temperature is high, adopt shading to cool down; when the temperature is low, heating equipment can be used to raise the temperature, thereby achieving a relatively suitable temperature, promoting orchid photosynthesis, and ensuring the healthy and rapid growth of orchids.
⑦ According to the phototropism of orchids. Orchids are phototropic, so the direction of the orchid pot should be rotated and adjusted at intervals, to prevent the plant's leaves from leaning to one side. In particular, the side with new growth should face the direction with sufficient light during the sprouting period, to facilitate sprouting and the healthy growth of shoots. If out of special needs for shaping or composition, in order to express a specific poetic or 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 and satisfying appreciation needs.
⑧ Regulate according to the growth condition of the orchids. Generally speaking, if the leaf color is pale green and the orchid leaves are thin, weak and leggy, then the light is too strong. If they are yellow-white or even scorched and withered, then it indicates that the light has exceeded the tolerance of the orchid plant. 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 orchids. 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. Both are abnormal and need timely adjustment.
⑨ Regulate light according to the growth period of orchids: during the growing period, the supplementary light time should be longer; during the dormancy period, a little less.
⑩ According to professional testing. (Excerpt)
(1) The light intensity for well-growing orchids is 4000-5000 Lux (lux, the unit of light intensity), and their sprouting rate, flowering rate, leaves and leaf color are all excellent.
(2) 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, better sunlight is also harmful and not beneficial to orchids.
(3) Plants most easily absorb red and blue light, and balanced red and blue light is especially important for photosynthesis. According to experiments, 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 growth, thereby helping orchids better accumulate nutrients.
(4) A certain intensity of long-wave ultraviolet light is also indispensable; it can help form anthocyanins and inhibit the elongation of branches and leaves.
2. Methods for regulating orchid light:
First, shading. In nature, orchids mostly grow in cool, shaded mountain forest environments with scattered sunlight, and semi-shade and shade-loving types account for more than four-fifths of all orchid plants. Therefore, when light is too strong, shading must be used to weaken the light.
(i) Plant shading. Imitating the natural environment, using plants for shade 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 vines such as grapes, honeysuckle, morning glory, Chinese trumpet creeper and cypress vine climb and spread over them, which both provides shade and is beautiful. Deciduous vines provide shade in summer and let light through in winter, which is a natural regulation. Trees can also be planted around the orchid garden, selecting evergreen trees, deciduous trees, bamboos and so on 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 and so on, with bamboo blinds, plastic film, shade nets and so on laid on top. On it, set a double layer of shade net 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 deployed or retracted. In midsummer use double layers; in spring and autumn use a single layer; on clear days at noon in summer and autumn use double layers, and on cloudy and rainy days a single layer. In winter, decide according to circumstances: on clear days deploy the lower layer, on cloudy days roll up the lower layer. In addition, before orchid flower buds are about to bloom, there must be moderate scattered sunlight, otherwise the flower color will be dim and not show its beauty. It is best to install the shade net as a movable type, so that the shading density can be increased or decreased as needed. The shade net should as much as possible not be pressed tightly against the plastic film or glass on the top of the shed, and there should also be a gap of about 30 cm between net layers. The shade net should be installed outside the plastic film or glass, so that the shading effect is good. If installed inside the shed, its shading effect is greatly reduced. When growing orchids on a balcony, at noon when direct sunlight is strong, and because walls have reflected light and radiant heat, and ventilation is also poorer than in a courtyard or orchid site, in the high-temperature season a 50% shade net should be hung outside the security grille for 3-4 hours around noon, to prevent scorching the orchids. 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, and low-altitude types need more than high-altitude types. In summer more shade is needed, in winter less shade; at noon more shade is needed, in the morning and evening less shade; at high temperatures more shade is needed, when cool less shade, and so on.
Second, "supplementary lighting." Regulating light in an orchid-growing site is not only about shading; when natural light is insufficient, artificial lighting also needs to be added to moderately supplement light for orchids, especially for indoor orchid growing and after the beginning of winter when the light time is short, which has a certain impact on orchid growth. Only by supplementing light to meet the light requirements of orchids can the orchid plants develop soundly, have sturdy stems, and grow and bloom.
(i) Basis for supplementary lighting. How to supplement light moderately, 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 artificially simulating the plant growth environment should also start from this. In addition to considering the light quality and light intensity necessary for orchid growth, artificial supplementary lighting also needs to consider the physiological radiation characteristics of the light source. (Light waves matching the characteristic curve of plant chlorophyll synthesis are called physiological radiation light sources, that is, photosynthetic light waves.) Under different light qualities, not only does the intensity of photosynthesis differ, but the photosynthetic products are not entirely the same either. 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 cannot be too strong, as it will scorch orchid leaves). Green light should also not be ignored; it can promote oxygen growth, thereby helping orchids better accumulate nutrients. In addition, a certain intensity of long-wave ultraviolet light is also indispensable; it can help form anthocyanins and inhibit the elongation of branches and leaves. Supplementary lighting must select a suitable light source according to the effects of the above spectrum and the growth condition of the orchids.
(ii) Light source selection. Because light quality has an obvious effect on the composition of photosynthetic products, people should choose a suitable light source 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 the 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 cheap. Of course, if conditions permit, it is best to choose plant lights specially designed for orchid supplementary lighting. 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 especially strong durability compared with ordinary lamps and also save electricity, reducing operating costs. When choosing a light source, one should consider not only light quality and light quantity, but also low power consumption, economy, durability and convenience of use.
(iii) Supplementary lighting time. After installing artificial lighting equipment in the orchid room, the supplementary lighting time should be determined according to the actual light conditions of the orchid-growing site, the seasonal changes in light, changes in weather and the growth period of the orchids. The supplementary lighting time also differs according to the different growth periods of orchids and the orchid-growing environment. For indoor orchid growing where light is not strong but scattered sunlight can enter, there should be no less than 5 hours of supplementary lighting; on balconies, no less than 4 hours of artificial supplementary lighting; basements and indoor spaces that see no sunlight should have no less than 10 hours of artificial supplementary lighting. During the orchid growing period, the supplementary lighting time should be longer, and during the dormancy period a little less. On cloudy, rainy and foggy days, there should be no less than about 10 hours of artificial supplementary lighting. Supplementary lighting time involves many factors and needs to be tested in practice to arrive at a relatively correct supplementary lighting time.
(iv) Lighting 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, so the height distance of the light tubes can be adjusted to regulate light intensity, to adapt to the moderate light requirements of different orchid species. How to choose the lighting distance: the installation distance of supplementary lights 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 and the temperature being too high, which would cause 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 better; for high-pressure sodium lamps (120W-400W), keeping a vertical distance of 1 m-1.5 m from the plants is more suitable. For LED supplementary light sources, because LED produces very little heat, they can illuminate at close range, and 10 cm is better.
(v) Light direction. To ensure the supplementary light intensity for orchids, the lamps should as much as possible be arranged directly above the orchids. Benefits: first, because of plant phototropism, with more overhead light, the orchid leaves grown have stronger uprightness, which suits 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 supplementary lighting.
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, causing orchid diseases. Ventilation can reduce heat.
③ Comprehensive configuration of light sources. To obtain a better supplementary lighting effect, 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 orchids' needs for various spectra during growth.
④ Pay attention to the installation safety of supplementary lighting fixtures to prevent accidents.
The above briefly describes the role of artificial supplementary lighting for orchids and some specific issues. In short, by moderately supplementing light for orchids and ensuring they have relatively sufficient light, this can not only improve the cold resistance of orchids when overwintering, but also ensure the vigorous growth and abundant flowering of orchids in the coming year.
Third, "hardening plants." Orchids have relatively strong adaptability to light, and this is also related to the number of generations exposed to light intensity. They will gradually change and adapt. For orchids that have always been grown in shade, 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 structure and function of plant leaves will develop in the direction of shade tolerance, 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 sufficient sunlight for photosynthesis. The folk so-called "hardening plants" roughly means this - letting orchids adapt to different environments - including light, temperature and so on. Through "hardening plants," they can be made stronger generation by generation.
Fourth, display. In the display of potted orchids, according to the habits of various orchids, those with high light requirements should be placed where light is most often available. Those with low light requirements should be placed in positions with little light. In addition, orchids are phototropic, so it is best to adjust the pot direction once or twice a month, to prevent the plant's leaves from leaning to one side. In particular, the side with new growth should face the direction with sufficient light during the sprouting period, to facilitate sprouting and the healthy growth of shoots.
In summary, light plays a crucial role in the growth, development, flowering and reproduction of orchid plants. Although orchids like 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 orchid life. 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, concentrations of carbon dioxide and oxygen, wind speed, temperature, water supply, inorganic nutrients, and pollutants in the atmosphere and soil, and so on. At the same time, light is also affected by the plant's own internal factors: for example, different orchid plants differ to a certain extent in their light time, 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 the above internal and external factors can the goal of raising the efficiency of plant photosynthesis be achieved, promoting the healthy development, growth and flowering of orchids.