A Complete Analysis of the Water Requirements of Chinese Orchid Cultivation

After understanding someorchidbasic theories of water metabolism, incultivationpractice, identify the water requirements of Chinese orchidcultivation. The root system of the orchid plant continuously absorbs water from thecultivationsubstrate to supply the needs of various physiological processes. Its water requirement varies according to species and developmental stage, and supplying too much or too little is detrimental to the orchid plant. Therefore, when the plant has a higher water requirement, an appropriate amount of water should be supplied. Generally speaking, when orchid plants are divided or collected from the mountains for planting, the first step is to place the orchid plants in a shady place and let the free water on the root system dry naturally. First, this allows the wounds on the injured orchid roots to form a protective layer, making them less susceptible to infection by pathogens and reducing the number of pathogens. Second, it makes the root system slightly soft, which facilitates planting. The cultivation substrate is divided into three categories: large, medium, and small. When planting, place the large-grade substrate at the bottom of the planting container, the medium-grade substrate in the middle, and the small-grade substrate on the top layer. This facilitates root fixation, growth, and water absorption, and the middle and lower layers achieve drainage and aeration to meet the physiological requirements of orchid roots. After planting is completed, soak the entire pot in a container for 15 minutes, then repeatedly drain and refill the water from top to bottom, so that impurities in the substrate that easily compact or clog the drainage holes and cause water accumulation are removed. Then, rinse the orchid plant with a faucet until the water flowing out of the pot holes is clear. Place it in the orchid shed and let it dry naturally until the substrate surface turns white before watering again to replenish moisture. This is mainly to let the substrate dry slightly, for the same reason as drying the root system before planting, because during the planting process the root system is damaged to varying degrees, and preventing wound infection is a relatively effective method. If not handled this way, the damaged old roots may all rot, affecting the growth of the orchid plant. In fact, smaller orchid plants have a small nutritional area, consume little water, and have a small water requirement. During the period of vigorous vegetative growth, the water requirement increases. During the senescence stage of the plant, or for some old, weak, diseased, or disabled plants, the water requirement decreases, and management should treat them accordingly. Watering should suit the growth needs of the orchid plant, and the interval should not be too long, so as to promote continuous growth of the orchid plant. The amount of water at each watering should not be too much, as excessive water can cause oxygen deficiency in the cultivation substrate and lead to adverse consequences. When watering, attention should be paid to water quality and water temperature. Polluted water or water that is too cold is unfavorable for Chineseorchids. It is generally believed that rainwater is best, but collecting and storing large amounts of rainwater is somewhat difficult, and with serious atmospheric pollution today, rainwater is not necessarily pure. Well water is now considered to have relatively good water quality, and its water temperature is also relatively constant. Tap water contains too much chloride, and directly spraying it onorchidswill cause harm, so tap water should be left to stand for a period of time to let the chloride in the water be released before use. When watering, use a spraying method to water the plants; the pressure should not be too high, as too much pressure will damage new shoots and tender leaves, and will also wash away the cultivation medium and expose the orchid roots. In some high-grade orchid rooms, a timed humidification method is adopted, which requires the cultivation substrate to be more free-draining, and ventilation must be strengthened. In this case, natural ventilation cannot meet the requirements, and ventilation devices such as blowers and exhaust fans must be installed. It is generally believed that for Chinese orchid cultivation sites requiring automatic humidification, the degree of humidification is best when the orchid leaves are not covered with water droplets or moisture stains. This is because orchid leaves being too wet for a long time affects photosynthesis, respiration, and the normal physiological functions of the root system, and easily causes "water injury" to orchid leaves, increasing the chance of disease infection. Usually, controlling the humidity in the orchid room at 70%-90% is more suitable, which can promote well-developed roots in orchid plants. In some constant-temperature orchid rooms that require air conditioners for cooling, because air conditioner cooling must reduce air humidity, it easily causes atmospheric drought, so humidification devices should be installed on the equipment to balance it. A relatively successful cooling method is to use water curtains for cooling. Because local microclimates differ from place to place, the water management measures adopted to satisfy the water metabolism oforchidplants also differ in emphasis, so it is necessary to proceed from actual conditions and create a set of practical and feasible systematic management plans to satisfy the water requirements of orchid plants. (Liu Zhongjian)