The relationship between orchids and water and watering methods

Sunlight, air and water are indispensable conditions for the growth of all living things. When scientists explore whether life exists on celestial bodies beyond the Earth, they mainly look at whether water exists there. Water isorchidsvery important; without water,orchidscannot grow. The ancients said "dry orchids, wet chrysanthemums," referring to the relative humidity requirements of these two kinds of flowers for the growing medium in the pot. Like chrysanthemums,orchidslikewise prefer moisture. Discussing the water supply for orchids should consider two aspects: first, water supply and water retention in the pot; second, environmental humidity retention. Orchids are acid-tolerant (H+) and alkali-averse (OH-) plants, and attention should be paid when using water. Most modern urban drinking water is disinfected with bleaching powder and still contains chlorine (Cl) when it leaves the plant. Since chlorine is toxic, tap water should be left to stand for one or two days before use. Rainwater must be tested with test paper before it can be used to water orchids; the pH value should preferably be between 5.5 and 6, and should not exceed 6.5. In recent years, the air in large and medium-sized cities has contained relatively high levels of fluorine (F) and sulfur (S), and acid rain occurs frequently. If water containing fluorine and sulfur is used to water orchids over a long period, the pot medium becomes too acidic,orchid plantsbecome poisoned, are prone to stem rot, and collapse. On windy days, or after a rain, the air is fresh, and the rainwater at such times is pure and can be fully utilized. Orchid pots should be allowed to be rained on more during moderate and light rain, while during heavy rain they should be covered with covering materials. Apart from using humus soil to grow orchids, we do not advocate using rice-washing water or water that has washed other substances to water orchids. Any water that has been used for washing will certainly carry impurities or organic matter, which will provide conditions for the reproduction of fungi, bacteria and viruses. Water flows from high places to low places, and watering orchids mainly relies on pouring water into the pot from the pot rim. Permeability and wetting ability are very important for supplying water to all parts of the orchid, and water can be poured directly onto leaf tips and flowers. However, if orchid roots are soaked for a long time, disease can result, so the pot should not hold too much water. Water has different evaporation rates as temperature rises and falls. At high temperatures, for potted orchids grown in granular media, the standing water in the pot may evaporate completely in four or five hours, so water must be replenished frequently. To understand orchid growing in one lesson, watering takes three years of skill. Whether orchids are grown well or not depends on whether they are watered well. Theorchid'sfungal root system is fleshy and relies on water to maintain vitality, and cannot lack water. But if there is too much water, the fungal roots are soaked excessively, and reverse osmosis can also occur, causing nutrients to be released, and over time this will cause rot. Therefore, the requirement is: do not water when dry, and when watering, water thoroughly. Especially in weather with relatively high humidity and relatively low temperature, the medium does not dry out easily, and water should not be applied frequently. If high-grade plants need to be grown, to be sure, the weighing method can be used. For strong plants, water when the medium has dried to 40% water content; if the plants are weaker, water only after it has dropped to 20% water content. In winter, it can be allowed to dry further before watering. But large granular media must not be too dry, lest airflow dry out the roots. Do not forget the ancient saying: "not dry in autumn, not wet in winter." We advocate that in dry spring and autumn weather, the air humidity should be maintained as much as possible. When spring winds are dry, spring shoots emerge late; when autumn winds are dry, the plants do not grow sufficiently. We do not advocate using the standing-in-water pot method. Water absorption by standing the pot is more suitable for humus, but for granular media it has the drawback of causing the growing medium to float up. For watering, it is best to use a fine-spout watering can to spray down over the entire pot surface from above, especially in summer, as this can wash away floating dust falling from the air, increase environmental humidity, and also wash the roots. The excretions from the root bark during growth can be washed out with the watering. How much water is contained in the pot can be seen roughly from the surface, and can also be judged from the holes in the pot wall and the bottom holes. If these holes are wet, it indicates that the pot is not short of water; if the weather is not hot, water should be appropriately withheld to prevent waterlogging. For the granular medium in theorchidpot, thorough water should be applied twice, at 10 a.m. and 2 p.m., both to replenish water and to wash the roots. At night, empty the pot to let air participate in growth activities, and also make full use of the evaporation of water vapor to maintain air humidity. During the growing season, humidity should be kept between 40% and 70%. On dry windy days in spring and autumn, special attention should be paid to this. When it is too low, spraying must be used to increase air humidity and protect orchid leaves. Humidity in the micro-environment is solved by spraying, and the orchid shed is best equipped with a commercially available humidifier. At low temperatures in winter, humidity should be kept at 30%-40%, and at other times 50%-70% is sufficient. Tap water is better stored for two days to let the chlorine volatilize before use. However, it should not be stored for a long time without use. Water stored in a large container for more than half a month is not suitable for watering. Because flowing water does not rot, while still water easily undergoes chemical changes. A water molecule is one oxygen and two hydrogens; under flowing conditions, the way hydrogen and oxygen atoms combine remains unchanged, and some oxygen is still dissolved in the water. After long storage, the originally dissolved oxygen will volatilize, and the water molecules will connect with each other into chains. When poured into the pot soil, they are not easily absorbed by orchid roots. Water stored for a long time should be stirred frequently so that chain-like water will not form when it is used. Some people store rainwater in large containers to water orchids, yet the orchids still always show signs of dehydration; this is precisely the reason. Also, purified water is not good for watering flowers, because so-called purified water mostly contains sodium (Na) ions, which can decompose water and release hydrogen, and is unfavorable for the orchid plant's absorption of nutrients. Different varieties of orchids also require different watering methods. For example, for flowers with an advantage in tall scapes, sufficient water should be given during the scape-elongation period; while for plants whose lateral sepals tend to hang down or curl backward easily, water should be appropriately withheld during flowering to keep the flower shape dignified. In addition, for orchid pots made of brick, tile and pond-bottom stone materials, 1% ferrous sulfate plus acid water should be applied once a month to prevent the medium from being too alkaline. And after spring flowering, nitrogen fertilizers such as urea should be used more, and sodium carbonate should be applied once or twice to prevent acidity from increasing, because when acidity is too strong, diseases such as anthracnose and southern blight are likely to occur. (Guan Wenchang, Zhu Hexing)