Detailed Explanation of Key Points of Mulch Cultivation Techniques for Gastrodia elata

For more than a decade, the author has studied, investigated, tested, summarized and promoted mulch cultivation techniques for Gastrodia elata in production areas across more than ten provinces and cities nationwide, which can increase Gastrodia elata yields by 20-30%. The principles and technical methods of yield increase through mulching are now introduced:

Principles of yield increase through mulching. Gastrodia elata is a plant that prefers cool temperatures and humidity. In nature it is mainly distributed under forests or in shrublands, mostly growing on gentle slopes at 10-30°C. During its growth period it likes moisture but fears waterlogging; it likes warmth, with the most suitable temperature being 20-25°C, but fears high temperatures, and growth stops when the temperature exceeds 28°C. However, for convenience and management, artificially cultivated Gastrodia elata is often not grown in forests. To prevent the cultivation site from being exposed to intense sunlight or heavy rain, fallen leaves or grass are spread over the Gastrodia elata cultivation site, on the one hand to retain moisture and prevent drought, and on the other hand to block sunlight and prevent high temperatures. In addition, the mulch can also suppress or block weed growth, achieving a water-retention effect.

(1) Mulch materials. The first is leaf type, with broadleaf tree fallen leaves being the best; leaves of pine, cypress, camphor and others can also be used. The second is grass type, with thatch being the best; rice straw, corn stalks and others can also be used.

(2) Mulch thickness. The thickness is 2-5cm; above 1000 m altitude it can be thinner, and below 1000 m it can be thicker.

(3) Mulching methods. Mulching is further divided into full mulching and partial mulching. Full mulching means covering both the cultivation boxes and the furrows of Gastrodia elata, while partial mulching means covering only the Gastrodia elata cultivation boxes and not the furrows. Mulching is also divided into direct mulching, which means placing the mulch directly on the Gastrodia elata cultivation boxes. Indirect mulching means building a shade shed over the Gastrodia elata cultivation site, or combining the two, that is, using direct mulching combined with indirect mulching. This method has a very obvious effect when applied in places at about 500 m altitude. Where conditions permit, mulching can be done while planting; when Gastrodia elata enters its vigorous growth season, especially in the three months of July, August and September, attention should be paid to mulching. It should be specially pointed out that drainage ditches must be opened well before mulching.

(4) Management after mulching. If Gastrodia elata is cultivated in November, after ditching and mulching, basically no management is needed until mid-May of the following year, but between mid-May and the end of September, regular inspections should be carried out and management should be conducted according to actual conditions. For fully mulched cultivation sites, the main task is to check dryness and humidity; for partially mulched cultivation sites, first check dryness and humidity, and second, regularly remove weeds between the furrows.

(5) Mulching with plastic film. In some places, during sexual reproduction, plastic film is used to cover Gastrodia elata seeds during the germination period to keep them warm and moist, with good results. However, in the process of asexual cultivation, if plastic film is also used for mulching, great attention must be paid to the timing and method of plastic film mulching. If the mulching method is improper, it will create four environments unfavorable to the growth of Gastrodia elata: first, increased temperature; second, excessive water accumulation; third, the film being left on for a long time without being removed, so rainwater cannot penetrate and moisture is insufficient; fourth, poor ventilation, while temperature and humidity are too high, leading to rot of Gastrodia elata. Therefore, when the temperature reaches above 20°C, plastic film mulching should not be used. If plastic film is used for mulching, an appropriate thickness of soil or fallen leaves should be covered on the film according to the situation.