A Complete Analysis of Gastrodia elata Cultivation and Processing Techniques

Gastrodia elata is a herbaceous plant with no leaves and no roots, and its underground tuber is used as medicine. It mainly treats hypertension, dizziness, headache, facial paralysis with deviated mouth and eyes, limb numbness, infantile convulsions (wind), and hemiplegia, among other conditions. It is also used for pilots' brain health and long-term dementia, among others, and is an ideal tonic for brain and nerve health.

1 Propagation of Gastrodia elata

1.1 Sexual propagation When a few Gastrodia elata plants send up aboveground stems and bloom, the sandy soil should be kept moist, the flower stems should be fixed with bamboo poles, and direct sunlight should be shaded. After the flower buds take shape, the flowers open one to several per day from bottom to top. If pollinating insects are lacking (bees can also be moved nearby and kept), artificial pollination should be used: use tweezers to open the corolla, remove the anther cap, take out the pollinia, and place them on the stigma. Pollination should be done between 10 a.m. and 4 p.m. If pollination succeeds, the ovary swells, the corolla withers, and the ovary sutures become obvious. Once it splits, a large number of seeds will be released. When one fruit splits, cut off the adjacent 3—5 fruits and place them in a dish to split naturally before collecting the seeds. The seeds scattered in the dish should be sown immediately and must not be left standing. Lift up the fungal material of the prepared fungal bed, and in the broadleaf tree leaves spread about 1 cm thick, scatter the seeds between the leaf layers, sowing the seeds of 10—20 fruits per square meter, then restore the fungal bed to its original state, scatter a layer of leaves, and cover with fill material. Let it grow strong Gastrodia elata and become a high-yielding hybrid seed tuber. When planting Gastrodia elata, make several fungal beds, do not remove the lower bed tubers, and prepare them for use in sexual propagation of Gastrodia elata.

1.2 Asexual propagation In October to November, when the ground temperature is 5—6°C, Armillaria mellea can grow. Gastrodia elata, however, needs about 10°C to begin sprouting, so Gastrodia elata planted in autumn and winter has a longer period of time, which facilitates the combination of Armillaria mellea and the seed tubers. When Gastrodia elata begins to sprout the following year, it can receive a sufficient nutrient supply. Therefore, autumn planting is the best season.

The method is: Site selection and pit digging: choose black sandy loam soil with humus, on mountain land that can filter water and retain warmth, or dig a pit in the courtyard. The depth is 25—30 cm, the width is 50—60 cm, and the length depends on the site. The bottom of the pit should have a 10—15 degree slope along the mountain direction to facilitate water flow. Prepare backfill soil: use black, loose soil from mountain broadleaf forests (old firewood base) as backfill soil; alternatively, choose fertile black mud on flat land plus sawdust, or soil plus rice husks, or the debris screened out after screening soybeans when threshing soybeans; bag the underscreen portion for later use; crush the overscreen portion and keep it for use. When harvesting sweet potatoes, cut the vines into one-inch lengths and dry them, crush them with a feed machine, transport them to the planting site, and mix them with sandy soil for preparation. The ratio of sawdust to sandy soil is 3:1 (volume ratio); the ratio of leaves (semi-rotted and crushed) to muddy sandy soil is 4:1; the ratio of rice husks (or soybean vines, sweet potato vine fragments) plus sand is 2:1, then cover with a layer of fine sand on top and cover well with withered grass and leaves.

To promote the growth and development of Armillaria mellea, phosphate fertilizer can be applied once when cultivating fungal sticks, that is, a 0.5%-1% potassium dihydrogen phosphate aqueous solution or a layer of ground calcium superphosphate, with 20—30 g used per pit, weighed and prepared for scattering. Arrangement of fungal sticks: first spread 5—6 cm deep mixed soil on the bottom of the pit, then scatter a layer of semi-rotted broadleaf tree leaves (not too thick), just enough to cover the soil. First place the lower layer, arranging 3—4 fungal sticks along the mountain slope direction, with a distance of 2—3 cm between sticks, and place 3—4 seed tubers close to the sticks between two sticks; when placing, the two growth points at both ends face outward, place 2 seed tubers at each cross end of the fungal sticks, and after placing them, cover with mixed soil up to the level of the sticks, then place another layer of fungal sticks and seed tubers in the same way, filling the gaps with soil. When arranging, the upper and lower sticks should be staggered. After the first layer is arranged, place 5 cm of mixed soil and then arrange the second layer of fungal sticks and seed tubers. On top place a layer of leaves, and finally cover with 7—10 cm of soil level with the ground. Fungal stick plus firewood cultivation method: this can enable Gastrodia elata to establish a symbiotic relationship with Armillaria mellea and also provide abundant nutrients for Armillaria mellea. During cultivation, fungal wood and new wood alternate, seed tubers should be placed close to the fungal sticks, and leaves should be scattered and soil filled in. Fungal bed cultivation method: dig the pit during the slack farming period in May—June, and put in fungal branch wood and new sticks. When planting, dig open the fungal bed, first dig out the upper layer of fungal sticks, do not move the lower layer of sticks, only use a small shovel to make a small hole between the lower layer sticks, put in the seed tubers, then place the upper layer sticks back in their original place (do not disturb the original sticks), place the seed tubers close to the fungal sticks, scatter 20 g of calcium superphosphate, fill the gaps with soil and cover with soil level with the ground. This method connects fungi quickly, has a high fungal connection rate, and also gives high yield.

Three-pronged cultivation method: namely, using artificially cultivated pure Armillaria mellea with sterile fresh sticks, and putting the seed tubers into the pit at the same time. Generally, the amount of fungal spawn used is 8—9 bottles per square meter, and seed tubers 1.5 kg. (Each square meter is 3 pits.)

2 Management after cultivation Seed tubers are put into the pit in October—November. The following April—May, weed once and prevent trampling by people and livestock. Drought prevention: in spring, Gastrodia elata has just begun to develop and grow and needs little water. June—August is its peak growth period. In case of drought, pay attention to watering to protect the buds. Young tender buds cannot adapt to adverse conditions, otherwise they are likely to dry up and die. For watering, use a hoe to gently dig a small hole at the upper end of the pit, then water so it seeps in, and after watering restore it to its original state. On flat land, water can be applied around the pit to seep in. At the same time, set up trellises and plant melons and fruits, letting the branches and vines provide shade. Waterlogging prevention: dig drainage ditches well. Freeze prevention: cover with weeds or a thick layer of leaves.

3 Prevention and control of diseases and insect pests (1) Mole crickets: locally called lala mole crickets. They can dig crisscrossing tunnels under the surface soil of the Gastrodia elata pit and chew on the tubers. Use 0.5 kg of 50% chlordane, 25 kg of wheat bran (fried until fragrant), add 7.5 kg of water, mix well, and scatter on the surface of the Gastrodia elata pit in the evening as poisoned bait. (2) White grubs: locally called ground silkworms (scarabs), which chew on Gastrodia elata inside the pit and make it hollow. Trichlorfon can be crushed and mixed with honey and placed on a dish to trap and kill them. Poisonous sweet potatoes can also be used: cut sweet potatoes into matchbox-sized pieces, soak them in 0.2% concentration 20% dimethoate solution, soak for 12—14 h, stir once, then soak for another 10 h, take them out and dry them in the sun, then use them for poisoning and killing. Place 3 pieces per pit; the effective period is 7 d. If they are not all killed in one application, apply several more times. More sweet potatoes can be cut, soaked in pesticide, and dried in the sun for later use. When drying and storing, strictly prevent children from eating them by mistake. (3) Ant damage: use ant-killing powder for control. At the same time, bury meat skin, meat, chicken bones, or fish bones near the Gastrodia elata affected by ants. After two days, dig and check. When ants gather, pour hot water to kill them. (A pot can be carried to build a temporary stove on site to boil hot water and pour it.) During the flowering period there may be aphids, and a 0.05% solution of 40% dimethoate emulsifiable concentrate can be sprayed. (4) Rat damage: use highly toxic rat poison to kill them. 4 Harvesting and processing of Gastrodia elata Harvesting: harvest in October—November. First dig out the fungal sticks, take out arrow tubers, white tubers, and rice tubers, handle them gently, transport them in grades, so as to avoid human mechanical damage and prevent tuber rot after planting. Grading: grade them by hand at the time of harvest. 3 liang (each liang = 50 g) or more is first grade, 1.5—3 liang is second grade; those below 1.5 liang and large ones broken during digging can only be counted as third grade. Washing off soil: wash the graded Gastrodia elata separately with water until clean. Do not rub off the mud; you may gently wipe off the muddy liquid by hand. Wash and process on the same day; do not wash first those that cannot be processed in time. Peeling: Gastrodia elata processed after peeling is called snow hemp. Now, because artificial cultivation is large in volume, except for export, the rest is not peeled. Steaming and boiling: after the water boils, steam and boil Gastrodia elata of different grades separately, adding a small amount of alum, 2 liang for 5 kg of Gastrodia elata. Those above 3 liang are boiled for 10—15 min, 2—3 liang for 7—10 min, those below 2 liang for 5—8 min, and off-grade ones for about 4 min. In short, the criterion is that they are cooked through (it is acceptable if no black core can be seen when looked at from a dark place toward a bright place). Drying: do not use too strong a fire when drying. The initial temperature on the drying pit should be 50—60°C. When dried to 70% dry, press the large ones flat by hand, do not press the small ones, and dry again. At this time, a temperature of 70°C is suitable. Sun-drying is also acceptable. After fully dry, take them out, grade, package, and they can be sold.