A Detailed Guide to Artificial Cultivation Techniques and Processing Methods for Gastrodia elata

Gastrodia elata is a parasitic herb. Its underground tuber is an important medicinal material, in great demand on both domestic and international markets. In recent years, the price of Gastrodia elata has remained firm, holding steady at 260-300 yuan per kilogram. In the past, Gastrodia elata was produced by vegetative propagation; because there was little planting stock of Gastrodia elata and it degenerated easily, both yield and quality could not meet demand, and it was in very short supply. Since last autumn, the market has turned brisk and prices have risen. The market transaction price for domestically grown first-grade Gastrodia elata is 280 yuan per kilogram, close to the historical high. The reasons are the social [market conditions], a sharp surge in demand, a decline in output, and an improvement in the export situation. Using artificial sexual propagation allows large-scale production, and the quality is good as well. Therefore, cultivating Gastrodia elata in good time is a good way for mountain farmers to get rich.

Although Gastrodia elata is a herb, it has no chlorophyll at all throughout its body and cannot manufacture nutrients itself; it must parasitize Armillaria mellea to obtain nutrients. However, Armillaria mellea is a fungus, and it too must parasitize the base of certain tree trunks, growing on the initial decay sap decomposed from them. Therefore, to artificially propagate Gastrodia elata, the relationship among these three must be well coordinated.

1. For the cultivation of Armillaria mellea material, use as much as possible

wild Armillaria mellea as the spawn, as it is relatively easy to manage. Armillaria mellea generally grows on fallen, half-rotted tree trunks or stumps at the edge of forests or by streams, and also in relatively moist soil rich in organic matter; it can be collected by hand and brought back for inoculation and cultivation. The tips of young rhizomorphs are red and can serve as good inoculation material; those with a dark brown surface are older rhizomorphs and can also be used for inoculation, but rhizomorphs whose surface is pure black, having completely aged, cannot be used for inoculation. Because new hyphae grow out from the cut surface of the rhizomorph, the collected rhizomorphs should be cut into small segments, each not too long, preferably 3-5 mm. To ensure the activity of the hyphae, the work must be done in a shaded and clean place, and contamination by foreign fungi must be avoided. Then the hyphae are cultivated on wood segments. Tree species suitable for Armillaria mellea propagation should be chosen for the wood segments, and this should be made clear at the time of collection.

2. For the cultivation of Gastrodia elata seeds, newly emerged wild Gastrodia elata can be collected as seedlings and cultivated in Armillaria mellea material until flowering, then hand-pollinated. This artificial sexual propagation raises the fruit-setting rate. Seeds are harvested in July-August and can then be sown in small pits. The small pits should preferably be 60-70 cm wide, about 100 cm long, and 28-35 cm deep, with ridges left between pits to facilitate the growth of the Gastrodia elata tubers outward. The optimum temperature for the vigorous growth period of Gastrodia elata and Armillaria mellea seedlings is 20-25°C, and the optimum humidity is about 80%. Sowing can be done at the appropriate time according to local conditions.

3. Before sowing Gastrodia elata seeds, first loosen the soil at the bottom of the pit and spread a layer of humus soil, then place the blocks of Armillaria mellea-inoculated wood material, filling the gaps with some broadleaf tree leaves. Alternatively, use only wood segments capable of cultivating Armillaria mellea mycelium; in that case, sprinkle finely cut wild rhizomorphs on the peeled places of the logs, then place the seeds on the fungal material at a spacing of 6-8 cm, cover with a layer of leaves, sawdust, or fine fibrous roots of herbs and grasses, and finally add a covering layer of soil. The humidity of the pit should be maintained at 45-60% year-round. After 2-3 years, it can be harvested. Large Gastrodia elata can be processed into dried commercial Gastrodia elata, and the small tubers produced can be used as seed Gastrodia elata to continue expanding production.

4. Gastrodia elata stops growing when the soil temperature reaches 10°C and enters dormancy; it resumes growth only when the soil temperature rises above 10°C. Gastrodia elata dug during this period has the best quality, so it is best to dig and process it during this period. When processing Gastrodia elata, first wash the outer skin with water, then rub off the scale leaves with rice husks plus a small amount of rice-washing water; cut off the stems of those that have them. For every 10 jin of fresh Gastrodia elata, add 2 liang of alum, and put it into boiling water to cook for 10-20 minutes; or separate them by size (to avoid uneven cooking) and steam them thoroughly in a steamer. When they are cooked or steamed until they feel soft when pinched by hand and appear semi-transparent with no solid core when held up to the light, they can be taken out and pressed flat with a wooden board. Dry them in the sun during the day, and at night dry them by a heated brick bed or beside a coal stove, or dry them further over a gentle fire. During drying, turn them frequently. When they are half-dry and the tubers feel soft, take them out, spread them to air and let them absorb moisture again, then dry them until completely dry. If over charcoal you add some sulfur-mud balls made by mixing 7-8% clay, 20-30% sulfur, and additional water and kneading them into coal-ball shapes for fumigation and drying, the Gastrodia elata can be made white and lustrous in color and can be prevented from insect damage.