What are the water requirements for Gastrodia elata cultivation?

Q: What are the water requirements of Gastrodia elata? How should proper water management be carried out?

A: As a plant, the main component of Gastrodia elata is water, which accounts for about 80% of the weight of fresh tubers - this is the foundation; however, since Gastrodia elata has no root hairs, it cannot absorb water from the soil and can only rely on Armillaria mellea to supply the necessary water - this is the main characteristic of Gastrodia elata; and the growth of Armillaria mellea also requires a corresponding water supply, and, determined by the symbiotic relationship between the two, they must coexist under the same environmental conditions. Therefore, a suitable moisture content in the sand becomes an indispensable and important condition. Under general natural conditions, through management measures such as shading and watering, maintaining the moisture content of the covering sand at about 10% and the humidity at 70%-80% is sufficient to meet the growth needs of Gastrodia elata and Armillaria mellea. The specific water management operation is: determine the specific amount of water used according to temperature, wind force or degree of dryness, etc. For example, under the climatic conditions of Shandong, before April, because evaporation is small and the growth rate of Armillaria mellea and Gastrodia elata is slow, the water requirement is relatively small, so there is no need for heavy irrigation. But if it enters May, with the arrival of dry hot winds, the rise in temperature increases evaporation, so water management should be strengthened. After July, when the ground temperature reaches above 28°C, Gastrodia elata is about to enter a summer dormancy state. At this time, if a large amount of water enters, on the one hand, appropriate water can effectively lower the temperature so that Gastrodia elata can continue to maintain its growth momentum; on the other hand, if the water is too much, it exactly satisfies the characteristic of Armillaria mellea liking abundant water, and it is very easy to cause "nutrient backflow," leading to "fungus absorbing the Gastrodia elata" and the occurrence of "rotten nest" phenomenon. In short, specific water management should be carried out according to the specific temperature and climate conditions and the growth pattern of Gastrodia elata, and one must absolutely avoid following what others say and copying blindly.