What basic conditions must be met for growing orchids?

The basic conditions for growing orchids are the same as for other flowers, grasses and trees, and include four aspects: temperature, humidity, light and ventilation. If these conditions all suit the requirements of the orchid varieties being grown, successful cultivation is basically guaranteed. 1. Temperature From seed germination to flowering and fruiting, orchids carry out all their processes under suitable temperature conditions. To promote normal growth in orchids, temperature conditions are especially important and are often the key to successful cultivation. Because the places of origin of various orchids differ, the temperatures they require also differ: some need relatively high temperatures all year round; some need high temperatures during the growing period but lower temperatures during the dormant period; and some orchids from temperate zones or high mountain areas need low or moderate temperatures to grow and flower normally. According to their different temperature requirements, orchids can be roughly divided into three major types: high-temperature, moderate-temperature and low-temperature: (1) High-temperature type: Most of these orchids are lowland species native to the tropics or subtropics, such as Phalaenopsis, Rhynchostylis, Aerides and Arachnis. For the growth of this type of orchid, the average winter nighttime temperature must be 18 degrees to 21 degrees, and the average daytime temperature 21 degrees to 24 degrees. If it falls below the above average temperatures, or if the day-night temperature difference changes too much, the growth and flowering of this type of orchid will be affected. (2) Moderate-temperature type: Most of these orchids come from subtropical or tropical high mountain areas, such as Cattleya, Oncidium, Dendrobium, Coelogyne, Miltonia and Paphiopedilum. The temperatures required by this type of orchid are: in winter, an average of 15 degrees to 18 degrees at night and an average of 21 degrees during the day; in summer, 21 degrees to 24 degrees at night and 26 degrees to 29 degrees during the day. If the winter temperature changes by more than 10 degrees, the growth and flowering of this type of orchid will be affected. (3) Low-temperature type: Most of these orchids are distributed in subtropical high mountains or temperate snowfall areas, such as Cypripedium, Masdevallia, Pleione and South American slipper orchids. The temperatures required by this type of orchid are: in winter, 10 degrees to 13 degrees at night and 15 degrees to 18 degrees during the day; in summer, nighttime temperatures should remain at 18 degrees to 20 degrees. If the temperature changes by more than 5 degrees within a day, their growth will be affected or they may rot and die. Although the above three types of orchids with different temperature requirements have a certain ability to adapt to higher or lower temperatures, they all need relatively stable average temperatures to grow well. In fact, the yearThe four seasonshave highly changeable climates, and temperatures change accordingly, so artificial temperature regulation becomes necessary. As for regulation methods, if in a front shed or open-air environment, when the temperature drops, plastic film can be used to cover them, or wooden boards and similar objects can be used to cover and block the wind. Conversely, if the temperature is too high, the covers should be opened again to allow ventilation and water should be sprinkled to absorb heat so as to lower the local temperature. If in a greenhouse when the weather turns cold, doors and windows should be kept tightly closed, and artificial heating should be used when necessary to raise the temperature. If the indoor temperature is too high on hot days, all doors and windows of the greenhouse should be opened, and sprinkling water can be used to lower the temperature. For a small indoor greenhouse at home, an electric fan can be used to cool it down and lower the indoor temperature. 2. Humidity Greenhousecultivationorchids most like an environment that maintains high humidity at all times, but excessive humidity easily induces rot disease and damages the orchid plants. Generally, orchids like to grow under humidity conditions below 90%. Generally speaking, terrestrial orchids need lower humidity, at 45%-65%, but some moisture-loving epiphytic orchids, such as Phalaenopsis, Odontoglossum and Vanda, during the growing period when the temperature is high, need humidity of 70%-80% during the day and 80%-90% at night. When the humidity in the greenhouse is too high, doors and windows can be opened for ventilation to disperse the moisture and thereby lower the humidity. When there is no wind, an electric fan can be used to blow air or heating can be used to lower the humidity. During continuous rainy weather, watering can be omitted to avoid excessive humidity. If the air is too dry, water can be sprinkled on the ground, walls and around the flower pots to increase humidity and reduce water loss from the orchid plants, so as to achieve the humidity conditions needed for normal growth. 3. Light For orchids, as for other flowers, light is very important. The strength of light directly affects the normal growth, flowering and fruiting of orchid plants. If light is insufficient, photosynthesis does not produce enough nutrients, so the orchid plants cannot flower; even if they do flower, the flower colors are not vivid. Conversely, some shade-loving orchids, if exposed to fierce light or scorching sunlight, will have their plants scorched, seriously affecting their growth. Because orchid species differ, the amount of light they need also differs. Generally, most species fear direct sunlight in summer and prefer scattered light conditions. Cattleya, Dendrobium, Vanda and Epidendrum need relatively strong light. In winter and spring they can be placed under full-sun conditions for growth, while in summer and autumn about 50% of the light amount is enough. Paphiopedilum, Phalaenopsis, Miltonia and others need a lower amount of light; 40% in the morning and 25%-30% in the afternoon is enough. 4. Ventilation Air circulation is very important to the health of orchid plants, because ventilation and air permeability not only promote the respiration of orchid plants and increase nutrient absorption, makingorchidsgrow vigorously. In addition, it can also regulate indoor air circulation, thereby regulating the indoor air temperature and humidity to suit their growth. Ventilation can also dry the leaf surfaces and the pot surfaces, reducing thepests and diseasesoccurrence. If indoor ventilation is poor, orchid plants are prone to scale insect disease. In short,growing orchidsthe site must have good ventilation to achieve goodcultivationresults. Li Shaoqiu, Hu Songhua