Environmental factors of orchids: humidity

Because humidity and temperature, light reasonable adjustment and balance is necessary for photosynthesis, so in the daytime to ensure a higher humidity, especially in the growing season. As mentioned above, most terrestrial orchids, including terrestrial orchids, absorb carbon dioxide and water during the day and emit carbon dioxide and water at night, so reduce humidity at night and do not spray after dusk. However, most thick-leaved epiphytes, such as Dendrobium, Catalan, etc., have stomata that open at night, so it is harmless to maintain proper humidity at night. But generally speaking, when the temperature drops, orchids have lower requirements for humidity, and low humidity is more tolerant of low temperatures. In the northern greenhouse, if the heating system fails in winter, do not spray and water.

Orchids are mostly born in tropical and subtropical humid environments and generally require higher air humidity. The humidity in tropical rain forest areas is generally 70%~90% in summer, and 60%~80% in subtropical areas of China, but it can be reduced to 40%~50% in winter. Therefore, the cultivation of orchids requires a humidity of not less than 70% in summer and 90% for special species such as black orchids; however, the winter dormancy period can be reduced to 50%, and the night is 10% to 20% lower than the daytime. The general rule of humidity requirements is: high in growing season, low in dormant season; high in daytime, low in night; high in tropical orchid, low in temperate orchid; high in epiphytic orchid, low in terrestrial orchid; high in high temperature, low in low temperature; high in sunny day, low in rainy day. However, humidity regulation should be treated differently according to specific conditions. For example, orchids grown in the Hengduan Mountains in western China often experience longer periods of drought in winter. Although there is fog at this time, they still have slightly lower requirements for humidity than orchids grown in other areas in winter.

Humidity can be adjusted mainly by spraying water on the ground, spraying water in the air and increasing the area of water storage tanks; humidity can be reduced by ventilation.

Sprinkling the ground is good for orchids. Greenhouse floor is best not to use cement, at least not all cement, because the soil floor after watering, evaporation will carry nutrients from the soil, can be absorbed by orchids. The ground should be kept moist, dry corners should be sprinkled, shelves, surrounding glass, and partitions can also be sprinkled to increase humidity and avoid contact with orchids. However, the whole ground shall not be flooded. The second is aerial spray (i.e. spray). If the greenhouse ground is sand, spray more, clay less; spray more in summer, less in winter. To keep the air moist and the leaves, flowers, buds and roots of plants do not retain water. Usually high temperature weather 3~4 times a day, cloudy once, winter is at most once. It is best to spray water after the sun comes out in the morning and when the sun is high in the afternoon. Do not spray water at dusk and night, and do not let the plant retain water into the night. In addition, the water temperature of the spray water is preferably close to the room temperature, and the water temperature is too high or too low. Only when the room temperature is too high can cold water be used to cool down. A certain number of water storage containers placed in the greenhouse can not only increase the humidity of the greenhouse, but also be used to irrigate flowers. Especially in northern greenhouses. Algae and other aquatic plants and fish can be cultured in the water reservoir, which can improve water quality and increase fertilizer. Water storage tank, water tank, pool, water tray, etc., can be informal form, according to local conditions. (Chen Xinqi, Ji Zhanhe)