Why ventilation must be emphasized when growing orchids

Orchids have relatively high environmental requirements during cultivation, and if ventilation measures in particular are not done well, it can easily prevent orchids from carrying out respiration and photosynthesis, which has a great impact on orchid growth. So how should orchids be ventilated?

Orchids

1. Orchid plants mostly become infected when the local environment's temperature and humidity are too high, and it is stuffy and unventilated, allowing pathogens and pests to spread quickly, especially aphids, whiteflies, scale insects, brown spot disease and southern blight, which are the most obvious.

2. Ventilation of the site and shade shed. The site should be as spacious as possible and located in a high place. Flower benches can be built from bricks and stones, or empty flower pots can be placed upside down with orchid pots on top, so that the orchid pots are 20 cm to 40 cm above the ground. Especially in places with poor ventilation, orchid pots should be placed as high as possible. Bamboo curtains and bamboo fences are used for the shade shed; they are cheap and good, and provide good ventilation.

3. If indoor ventilation and air exchange are poor, the proportional relationships among the various gases in the air will change, harmful gases will increase and useful gases will decrease, affecting the growth and development of orchids, making them prone to mold and rot diseases, and they may even suffer poisoning. For houses, closed plastic sheds or glass sheds, especially those heated with coal, when the indoor temperature exceeds 10°C, windows should be opened or the film lifted every day. In winter, in rooms sealed on all sides, an electric fan should also be used to direct exhaust during the high temperatures at noon. The temperature in a greenhouse is generally higher above and lower below, so the air inlet should be at the lower part and the air outlet at the upper part; this gives faster ventilation and more thoroughly removes harmful gases. Note that while ventilating, spraying water should also be coordinated, the relationship among ventilation, heat preservation and humidity retention should be handled well, and cold wind should be prevented from blowing directly. The density of orchid pots placed indoors should preferably be sparse rather than dense, maintaining sufficient distance. If the area is narrow, the flower bench can be built in stepped form. The surface of orchid pots should often be rinsed with water, and the front and back of orchid leaves should be sprayed to ensure that the stomata remain unobstructed.

Orchid cultivation methods, precautions and techniques for growing orchids

Orchids include Cymbidium goeringii (spring orchid), Cymbidium ensifolium (sword-leaf orchid), Cymbidium sinense (Chinese cymbidium), Cymbidium faberi (nine-headed orchid), Cymbidium kanran, autumn orchid, cold orchid, and so on. There are many varieties, they bloom in all four seasons, and their color and fragrance are both superb, making them very appealing. Orchids like fertile, loose, slightly acidic soil. The leaves are long and narrow, and the inflorescence has sheath-like bracts; some are upright and some droop. The flowers are elegant and fragrant. There has long been a saying that "with an orchid in the room, no incense needs to be burned." Below, let us look at orchid cultivation methods, techniques and precautions.

The soil used for orchids should be mainly humus, primarily leaf mold or mountain forest humus soil. In the south, humus soil from the place of origin is used, commonly known as orchid mud; leaf mold, vermiculite, perlite and so on can also be used to manually prepare a loose, airy, water-permeable growing medium. Generally, 8 parts leaf mold and 2 parts river sand are mixed into the growing medium, or 7 parts leaf mold, 2 parts perlite and 1 part river sand are mixed into the growing medium, or 6 parts leaf mold (peat soil), 3 parts compost soil and 1 part river sand are mixed evenly into the growing medium. The growing media prepared above are all slightly acidic.

For fertilizing orchids, first, base fertilizer is applied into the growing medium, and second, topdressing is applied during the growing period. Topdressing mostly uses liquid fertilizer or foliar fertilizer, and the concentration should be lighter than for other flowers. Orchids should have their growing medium replaced once a year, and during the growth period topdressing can be applied sparingly, with attention to timing. Generally, during the growing season, fully decomposed dilute cake fertilizer water of about 15% can be applied as topdressing, or 0.1% urea fertilizer water plus 0.2% potassium dihydrogen phosphate fertilizer water, applied once every 15-20 days; from before flowering to the flowering period, 0.2% potassium dihydrogen phosphate or plant ash water can be sprayed on the leaves 2-3 times to promote the development of roots, stems and flowers. Orchids have fleshy roots, so undecomposed fertilizer must not be applied, to avoid root rot.

Watering orchids should be based on the species, growth conditions and local climate, and should achieve moistness without wetness and dryness without parching; watering should not be too much or too little, and the principle of "not dry in autumn, not wet in winter" should be mastered. In winter, when temperatures are low, plants are in a dormant state and watering should be controlled, generally once every 5-7 days, but Cymbidium sinense, which blooms in winter, needs more water;

In spring and autumn, water once every 2-3 days; in summer, when temperatures are high and orchids are in their vigorous growth period, water an average of 1 to 2 times per day. When watering, take care to prevent water droplets from splashing onto the leaves, so as to avoid black spots that affect the ornamental effect. During the orchid growth period, water should often be sprayed on the leaves, and in summer water should also be sprinkled on the ground around the flower pot to increase air humidity and promote orchid growth and development. For watering orchids, rainwater and snow water are best; if tap water is used, it should be stored for 2-3 days before use.

For potted orchids in the north, they should be moved indoors around the Frost's Descent solar term when the temperature drops to 5°C, and in the early period after being brought indoors, windows should often be opened to keep the air circulating. In winter, the indoor temperature should preferably be maintained at around 10°C. After Grain Rain, they can be moved outside for care. The suitable temperature for orchid growth is 16-24°C. In winter, the indoor temperature is generally required to be relatively low, preferably 10-12°C during the day and 5-10°C at night, and the temperature and humidity should not be too high; in summer, the temperature should not exceed 30°C.

Orchids like shade and fear direct strong light, so shade should be provided in spring, summer and autumn. For growing orchids at home, in order to control the amount of light, it is best to place them on a balcony windowsill or under the eaves with bamboo curtain shading, generally providing shade from 9 a.m. to before 6 p.m., and pulling the curtains open in the morning and after 6 p.m. so they receive scattered sunlight. In winter, they should be moved indoors to a place with visible scattered light, but direct sunlight should still be avoided. Among orchids, Cymbidium sinense has the strongest shade tolerance, followed by Cymbidium ensifolium, while Cymbidium goeringii and Cymbidium faberi have weaker shade tolerance.

The environment for cultivating orchids should have good ventilation, humid air and no pollution. Orchid pots should be tall pots, thick at the top and narrow at the bottom, with multiple drainage holes, or with drainage holes in the pot wall. The orchid pot itself should also have ornamental value.

Because orchids grow slowly, they can be repotted once every 1-2 years after the flowers fade. When potting, first place about 3 cm of tile pieces, furnace slag and so on in the bottom of the pot to aid drainage. Then put in a layer of growing medium, place the orchid seedling in the center of the pot, straighten the roots and let them spread naturally, and when the soil has been filled to halfway, lift the orchid seedling gently while shaking the pot so that the soil and roots combine closely. When the soil is filled to 2-3 cm below the pot rim, press it lightly with the hand. After planting, water thoroughly and place in a cool place, spraying water once each morning and afternoon, and after about 7-10 days move it to a shady place with dappled light for care.

Peat soil, black mountain soil, pine needle soil, garden soil, fern roots, moss and bark chunks can all serve as orchid growing medium. The bottom of the pot should have good drainage and increased permeability; tile pieces can be used to cover the drainage holes, then a layer of broken brick and stone particles with a thickness of one quarter of the pot's bottom depth, and finally the growing medium spread on top. When planting orchids, they should be held upright and inserted into the soil, then covered with soil up to the pseudobulb. Press the soil firm, leaving no soil within two cm, to make watering convenient. After planting, water thoroughly and place in a cool environment, then after half a month move into a ventilated, sunny environment. The pot surface can be covered with small gravel, which both retains moisture and enhances the ornamental value. Soil selection:

As mentioned above, "do not take them out in spring, do not expose them to the sun in summer, do not let them dry out in autumn, do not keep them wet in winter" - this is the cultivation principle orchids need to follow. That is, in spring, because of the temperature, taking them out of the room makes them prone to cold and affects their growth, so taking them out in April is more appropriate. In summer, under the shade shed, direct sunlight must be avoided, and appropriate shading can be provided. Autumn is the period when orchids sprout and send up flower spikes, so maintaining humidity is especially important. In winter, watering needs to be controlled, because their water requirement is low, and too much water easily triggers root and leaf diseases.

When applying fertilizer, strong concentrations should be avoided, so during the growing period, horse hoof paste residue water, soybean cake water and so on can be used once every half month. If potassium dihydrogen phosphate is applied in an appropriate amount, the effect is even better. Fertilizing in the hot summer season is not appropriate, because the temperature is too high, water is lost quickly, the fertilizer concentration becomes thicker, and plant growth is affected. In addition, daily watering is needed, and water should be sprayed on the leaves several times. The water should be slightly acidic, which benefits plant growth.

During orchid cultivation, the plants need pruning; for example, when old leaves turn yellow and wither, they all need to be pruned, which both benefits the growth of other leaves and allows ventilation. Diseased leaves especially need timely pruning to prevent contagion. In addition, scissors also need to be disinfected to prevent infection.

1. Do not use too large a pot - planting a small plant in a large pot uses a lot of medium, easily leading to poor aeration, and watering is also hard to control. If too much water is absorbed, the medium is not easy to dry, bacteria invade and cause root rot.

2. Orchids should be planted shallowly - orchid plants must not be planted too deep, otherwise long-term moisture will cause rot. When planting, the medium should fill the roots, and the base or pseudobulb must be exposed.

3. The roots should be spread out - when planting orchids, the roots should be spread evenly, not squeezed together, so that each root can contact the medium, and aeration is also better.

4. Do not water for several days - newly planted orchids may have injured roots; after the wounds are coated with fungicide, do not water for 3-5 days, so the pesticide effect can be achieved and the growth of new shoots and new roots can also be promoted.

5. Avoid strong light - newly planted orchids must all avoid direct strong light to prevent dehydration, and should be placed in a warm, shaded place; spraying can be used to increase air humidity until the orchids return to normal growth.

Orchids mostly use division propagation and tissue culture propagation, while seed sowing is used to breed varieties.

Division is carried out in spring and autumn, and varies by species. Species that bloom in winter and spring should be divided in late autumn; species that bloom in summer and autumn should be divided in early spring before budding. Generally, divide once every 2-3 years. Before division, watering should be reduced so that the pot soil is suitably dry; when dividing, hold the pot with the hands and gently knock the mother plant out of the pot, remove the soil, cut off rotten roots and leaves, then wash clean with water and place in a shady spot to air-dry for 3-5 hours. When the surface water has disappeared and the roots turn white, soften and slightly shrink, use a sharp knife to cut from the middle of the pseudobulb, coat the cut with plant ash for antisepsis, and plant immediately after drying in the shade. Be careful during division to avoid bruising leaf buds and fleshy roots. After potting, place in a shady spot, and after growth resumes transfer to normal management.

In recent years, China has used tissue culture technology for large-scale orchid production. Besides propagating orchids, tissue culture technology is also widely used to propagate Phalaenopsis, Cymbidium hybridum, Dendrobium and other foreign orchids.

What should be noted during the planting of white orchid (Michelia alba) - complete orchid information

[Orchid question]:

May I ask what should be noted during the planting of white orchid (Michelia alba)? How should fertilization be carried out?

[Expert reply]: