Method for ridge cultivation of Gastrodia elata in plastic greenhouses

Cultivating Gastrodia elata in ridges inside plastic greenhouses can be done on either a large or small scale, with low investment, high returns, and savings in labor, effort, and arable land. It requires no fertilizer, no pesticide spraying, and no weeding, and delivers significant economic benefits. The technique is described below:

1. Site selection: It is advisable to choose a shady slope or a gentle slope with half shade and half sun, sandy soil with good permeability, and slightly acidic or neutral soil with a pH of 5.5-6.0 for building the site.

2. Greenhouse construction: Follow the construction method for vegetable greenhouses, facing north and south, with the size determined by the scale of Gastrodia elata cultivation, generally 8 m wide and the length depending on the terrain and scale, with the front and back walls each 1.3 m high. Leave one ventilation window 40 cm high and 1 m wide every 3 m in both the front and back walls. Use 16# steel bars or bamboo strips to make an arched frame, cover the frame with 1 plastic woven bag, cover the woven bag with 10 cm of rice or wheat straw, seal and compact plastic film over the straw, and cover the film with a layer of straw matting. This kind of plastic greenhouse can keep warm in winter and also prevent rain, provide shade, and lower temperature in summer, creating suitable environmental conditions for the growth of Gastrodia elata.

3. Pre-sowing preparation: Calculate the required materials per square meter. Generally, for 1 sq m, prepare 30 kg of oak wood sticks 3-6 cm in diameter and 60 cm long, soak them in 0.25% ammonium nitrate solution for 6-12 hours, and cut 1 fish-scale notch every 10 cm on the sticks, cutting 3 sides in total. At the same time prepare: 400 kg of clean, pollution-free medium-coarse river sand, preferably rinsed once with clear water 6 hours before use; 1 kg of fallen oak leaves, which need to be soaked in clear water for 4 hours before use, then drained of water for later use; 3 kg of oak branches 1.5 cm in diameter and 6 cm long; 5 bottles (2.5 kg) of Armillaria mellea spawn, 2 bottles (or 2 bags) of germination-promoting fungus, and 16-20 Gastrodia elata capsules. During operation, first cut the germination-promoting fungus (because oak fallen leaves were used as the culture medium when producing the germination-promoting fungus) into small pieces about 1.5 cm square with a sharp knife and put them into a clean basin, then gently pinch the Gastrodia elata capsules by hand so that the longitudinal dehiscence line opens, shake the Gastrodia elata seeds into the germination-promoting fungus in the basin, mix evenly with both hands, turning and mixing once for each capsule shaken out, and also crush the capsule skins and sprinkle them into the germination-promoting fungus, mix evenly and wait to sow.

4. Sowing method: When sowing, first spread 10 cm of river sand on the ground inside the plastic greenhouse, then scatter a layer of soaked fallen oak leaves and pat flat, then evenly scatter the germination-promoting fungus fragments mixed with Gastrodia elata seeds onto the leaf layer, then place the prepared oak wood sticks on the sowing layer, with 5 cm between sticks, placing about 9 sticks per layer per square meter (15 kg), then place Armillaria mellea spawn at the fish-scale notches and at both ends of the wood sticks, then place small oak sticks 1.5 cm in diameter and 6 cm long diagonally between the large oak sticks to guide Armillaria mellea onto the sticks, and finally cover with 5 cm of river sand. After sowing the second layer in the same way, cover with 15 cm of river sand and pat flat.

5. Post-sowing management: 15-25 days after sowing, lightly spray water once on the surface of the Gastrodia elata ridge. After 15-20 days, when the Gastrodia elata seeds have germinated and Armillaria mellea has connected with the oak wood sticks, spray 1 heavy watering. After that, keep the sand moist, with humidity controlled at 40%-55%. Especially in the higher temperatures of early to mid-July and August, do not spray heavy water; keep the substrate humidity below 40%, pay attention to ventilation and air exchange, and spray cool water into the air to lower the temperature. From mid-to-late August to September, when the temperature is 20-25°C, this is the peak growth period of Gastrodia elata, and 1 heavy watering can be given every 15-20 days. After October, as the temperature gradually drops, under normal circumstances no watering is needed.

6. Transplanting: ① Harvesting Gastrodia elata: For Gastrodia elata sown in June, in order to expand cultivation, it can be harvested and transplanted in November of the same year, or harvested and transplanted in March of the following year. If you want Gastrodia elata to grow into finished tubers (large white tubers or arrow tubers) or seed tubers (arrow tubers for seed use), it can be harvested or transplanted in November of the following year. The harvesting time of Gastrodia elata is best carried out at the same time as transplanting. When harvesting Gastrodia elata, first remove the upper layer of sand, then slowly lift the fungus sticks and dig out the Gastrodia elata. Arrow tubers, large white tubers, medium and small white tubers, and rice tubers are collected separately for different uses. Harvest the second layer in the same way. The harvested arrow tubers or large white tubers are processed into commercial tubers; some arrow tubers are to be used as seed tubers for sexual reproduction; medium and small white tubers and rice tubers are used for asexual propagation and cultivation. ② Transplanting Gastrodia elata: First spread 5 cm of river sand on the ground, level it, then place 1 old fungus stick left from harvesting Gastrodia elata every 5 cm, and 1 newly cut oak stick with fish-scale notches soaked in ammonium nitrate solution, with small oak sticks 1.5 cm in diameter and 6 cm long placed diagonally between the old fungus sticks and the new wood sticks. Scatter a layer of sand to bury half of the fungus sticks. Place 1 Gastrodia elata transplant every 3-6 cm on both sides near the old fungus sticks. The plant spacing for medium white tubers is 6 cm, for small white tubers 3-5 cm, and rice tubers can be broadcast sown. After the Gastrodia elata transplants are placed, Armillaria mellea fragments can also be scattered; if the old fungus material is very good, the Armillaria mellea fragments may be omitted. Cover with 5 cm of river sand, cultivate the second layer in the same way, and then cover with 15 cm of river sand. In winter, pay attention to covering with grass to keep warm and prevent cold. Try to keep the temperature at 20-27°C.

7. Management of Gastrodia elata: ① After November, as the temperature gradually drops, pay attention to overwintering and cold protection for Gastrodia elata. When the ground temperature drops to 3-5°C, cover the surface of the Gastrodia elata ridge with 5-10 cm of wheat straw or rice straw to keep warm and prevent freezing. ② In spring, when the temperature stabilizes above 8°C, remove the covering grass, and it is suitable to keep the humidity at about 30%. When the temperature rises to 16-18°C, spray 1 heavy watering, and it is suitable to keep the humidity at 40%-50%. ③ In summer, when the temperature is higher than 28-30°C, Gastrodia elata stops growing and enters summer dormancy; at this time, watering should be controlled, and the humidity within the cultivation ridge layer should be kept at 30%-40%. Open doors and windows every night for ventilation and air exchange, and spray water into the air at noon to lower the temperature, so as to prevent Gastrodia elata from rotting. During the rainy season, pay attention to draining accumulated water. ④ In autumn, when the temperature gradually drops to 20-25°C, this is the vigorous growth period of Gastrodia elata; the humidity within the cultivation ridge layer should be kept at 50%-55%. As the temperature continues to drop, the humidity should also gradually decrease. When the temperature is 10%-16%, the humidity should be kept at about 30%. By November, Gastrodia elata will enter dormancy, which is the best period for harvesting and transplanting.