How can Gastrodia elata in the Changbai Mountains of Jilin be protected from frost damage in years with little snow?

Wild Gastrodia elata in the Changbai Mountains of Jilin is mostly distributed in high-mountain broad-leaved mixed forests at an altitude of 500-2500 m with cool and humid summers, deep winter snow cover, high ground coverage, a thick layer of fallen branches and leaves, a relatively shallow frozen layer, and loose soil.

Wild Gastrodia elata suffers frost damage in winters with little snowfall and a thick frozen layer, and cultivated Gastrodia elata also suffers frost damage when cold-protection measures are inadequate. In both 1981 and 1982, heavy snow sealed the ground, with winter snow 80 cm thick; when the snow was broken open, the frozen layer on the ground was found to be only 3 cm, so neither wild nor cultivated Gastrodia elata suffered frost damage. People called these "bumper years for Gastrodia elata." In the late autumn of 1983, after several consecutive moderate rains mixed with snow, severe freezing followed, and with little snow in early winter, the snow layer was only 15 cm thick; when the snow was broken open, the frozen layer reached 70 cm, and in a few places where the ground was exposed, the frozen layer reached 180 cm. As a result, Gastrodia elata suffered frost damage. People called this a "poor year for Gastrodia elata." Note: "bumper years and poor years" refer to wild Gastrodia elata.

So how can frost damage to Gastrodia elata be prevented?

① For pit cultivation of Gastrodia elata, in order to protect it from losses caused by frost damage, in August-September of the year before planting, use fixed fungus beds to culture Armillaria mellea well. The seed tubers of Gastrodia elata are overwintered indoors. After the ground thaws in early spring of the second year, use fixed fungus beds to cultivate large and medium white tubers. Harvesting in autumn can avoid frost damage and achieve relatively ideal Gastrodia elata yields.

② For pit cultivation of Gastrodia elata in high-cold regions, plant early at the right time. Generally, it is best to plant from late September to early October. This allows the Gastrodia elata to fully integrate with the soil, connect with Armillaria mellea earlier, and enhance its cold resistance.

③ For autumn pit cultivation of Gastrodia elata, strictly select seed tubers. Choose small white tubers and rice-sized tubers with strong vitality as seed tubers.

④ For overwintering in pit-cultivated Gastrodia elata, the humidity should preferably be kept at 30%. For large-area pit cultivation of Gastrodia elata, before overwintering, cover with tar felt paper or plastic film to protect against rain, and also clear the drainage ditches to prevent accumulated water from intruding into the pit, causing excessive humidity inside and leading to tuber rot and frost damage.

⑤ Add cold-protection measures and thicken the cold-protection layer. When using soil for cold protection, first cover with 15 cm of fallen leaves, then cover with 15-20 cm of cold-protection soil. Where there are no fallen leaves, double-layer tar felt paper or plastic film can be placed over the Gastrodia elata pit instead of fallen leaves. In addition, where conditions permit, covering with only 15 cm of dry sawdust can achieve the purpose of cold protection.