How to control water during orchid cultivation

Orchids are native to mountain forests, mostly growing in clusters in places facing southeast with their backs to the northwest, and where there is plenty of stone debris and humus. Mixed coniferous and broadleaf forests provide them with shade conditions, ventilation is neither strong nor weak, and there is often air movement containing a certain amount of humidity. Stone debris and humus drain well, do not easily accumulate water, and can also retain a certain amount of moisture and nutrients. Therefore, orchids are not dryland or wetland plants, but rather neutral plants that lean toward dryness. Orchid roots and orchid stems can store a large amount of water, while the cuticle of orchid leaves can reduce water evaporation, so orchids do not need too much water.

The suitable relative humidity for orchids is around 80%, and the potting soil humidity is around 50%. If the potting soil is too dry, the roots will shrivel; if the potting soil is too wet, the roots will rot. The orchid-growing experience summarized by predecessors is “orchids like moisture but fear wetness, like dryness but fear parching.” Therefore, orchid cultivation must be adapted to local conditions and must not be copied mechanically; it should be grasped and applied flexibly according to different seasons, environments, varieties, growth stages, and different pots and soils.

Different seasons

Seasonal changes cause temperature changes, and as temperature changes, the water requirement of orchids also changes accordingly. At the same time, because of temperature changes, the speed of water evaporation also changes. Therefore, the frequency and amount of watering orchids must inevitably change.

First, watering must change with the times, and the amount of watering should be determined according to the speed of plant absorption and evaporation. In summer, the temperature is high, orchids grow vigorously, and the water they need is greater. At the same time, water evaporates quickly, so they should be watered in both the morning and evening, and misting should be carried out to increase air humidity. Spring is the best growing period for orchids, and the water requirement is great, but evaporation is slower, so the amount of watering can be gradually increased in sequence from early spring to mid-spring to late spring. In autumn, the amount of watering can be gradually reduced in sequence from the Beginning of Autumn to mid-autumn to late autumn. However, during dry periods in autumn, water evaporates relatively quickly, so a moderate increase in watering is needed. In winter, the temperature is low and evaporation is slow, so orchids need less water and watering should be reduced. Reducing the water content in orchids' bodies in winter can also increase the concentration of cell sap and enhance their cold resistance.

Second, watering times differ at different temperatures. In summer, when the daytime temperature is above 30°C and the nighttime temperature is around 25°C, watering should be done when the temperature is at its lowest. In spring and autumn, when the daytime temperature is around 20°C and the nighttime temperature is around 10°C, watering in the morning is better. In winter, when the daytime temperature is around 15°C and the nighttime temperature is around 5°C, watering can be done at noon. Simply put, watering in summer should be done when it is cool, and watering in winter should be done when it is warm, and the following should be achieved: sufficient in spring, enough in summer, not dry in autumn, not wet in winter. Also note that you should water more on sunny days, less on cloudy days, and not at all on rainy days.

Different environments

In the process of growing orchids, air humidity and watering are very closely related. This is because in places where orchids are artificially cultivated, there are rarely environments and conditions identical to their native habitat. When ventilation is good and air humidity is low, moisture on orchid leaves and in the pot evaporates quickly, so the amount of watering should be increased; if ventilation conditions are poor, excessive watering will lead to excessively high humidity, and at this time the amount of watering can be appropriately reduced; if the temperature is high and orchids grow in muggy environmental conditions, a large amount of watering will make them sick, causing blackened leaf tips and black spots on the leaf surface; on cloudy and rainy days, humidity is high, and if ventilation conditions are good, even if the pot is dry, watering may be omitted; when cultivated outdoors, they can be allowed to receive rain to save the trouble of watering, but if a sudden shower occurs under a blazing sun and they are allowed to be rained on, it is easy for heat to accumulate inside; cold rain in early spring and late autumn must not be allowed to fall on them.

Different plants

Different orchid varieties require different amounts of water. The suitable temperature for Cymbidium goeringii, Cymbidium faberi, and Cymbidium kanran is 18°C to 24°C, while for Cymbidium sinense and Cymbidium ensifolium it is 25°C to 28°C. Therefore, Cymbidium goeringii, Cymbidium faberi, and Cymbidium kanran should be watered less, while Cymbidium sinense and Cymbidium ensifolium should be watered more.

Orchid plants differ in size and in strength or weakness, and orchids with different growth conditions also need different amounts of water. Newly transplanted orchids, because of repotting and division, will have some wounds on the plants, so watering should not be too frequent. Small seedlings, weak plants, and old plants have poor ability to withstand environmental changes, so the range of wet-dry fluctuation should be small, and it is enough to keep them appropriately moist. During the period from when new buds begin to grow until they mature, the amount of watering should gradually increase, and as the new seedlings mature, the amount of watering should slowly decrease again. At the beginning, the increase in watering amount should be determined according to the growth speed of the new buds; after the new seedlings grow up, the purpose of reducing the amount of watering is to promote the enlargement and maturation of the pseudobulbs. During new bud growth (vegetative growth), water should be sufficient, while when flower buds are forming, the water supply should be relatively reduced, and plants that already have flower buds especially should not be too dry or too wet. After flowering, the amount of watering should also be slightly reduced to keep the pot relatively dry, so that the orchids can rest and recuperate.

Different pots and soils

Pots and soil are the living quarters of orchid plants, and as the saying goes, “to grow orchids, first grow the roots.” Commonly used pots include clay pots, purple clay pots, plastic pots, and so on. Relatively speaking, clay pots dry the fastest, perforated plastic pots are next, and purple clay pots dry the slowest. Orchids in clay pots should be watered thoroughly each time, while for orchids in purple clay pots and plastic pots, watering and misting should be combined, watering one day and misting the next.

Soil is the growing medium for orchids and plays a key role in orchid growth. Generally, orchid growing media are required to be loose, breathable, and well-draining, but each place should grasp this differently. The mountain soil in the Jiangsu-Zhejiang area has relatively poor ventilation and water permeability, so watering should not be too frequent; Emei Xiantu has relatively good breathability and does not easily accumulate water, so more watering is possible; Yunnan humus soil has good breathability and dries easily, so it should be watered in time.