What are the key cultivation techniques for Gastrodia elata? A detailed explanation

Gastrodia elata, also known as red arrow, is a perennial herbaceous parasitic plant of the Orchidaceae family. It is suited to growing at high altitudes, where summers are cool and humid, winters are snowy and cold, forest trees are dense, the layer of fallen branches and leaves is thick, humus coverage is extensive, the surface soil is loose, and water retention and drainage are good.

Biological characteristics: Gastrodia elata lives symbiotically with Armillaria mellea. It has no seedlings and no roots; underground there is only a fleshy, thick, oval-shaped tuber. At the tip there is the arrow tuber with a red mixed bud, the white-headed bud without an obvious terminal bud (used for planting), and the rice tuber.

1. Terrain selection: In our county, the suitable area for planting Gastrodia elata is at an altitude of 1000-1800 m, and it can be planted on gentle slopes on both shady and sunny sides. At high altitude, the temperature is somewhat low and the humidity is relatively high, so Gastrodia elata grows slowly. At low altitude, the summer heat significantly inhibits the growth of both Gastrodia elata and Armillaria mellea.

2. Climatic conditions:

① Temperature is the primary factor affecting the growth of Gastrodia elata. Gastrodia elata prefers to grow in an environment that is cool in summer and not too severely cold in winter. When the temperature rises in spring and the ground temperature reaches about 12°C, the Gastrodia elata that has been dormant in winter begins to sprout and grow. When the ground temperature reaches above 15°C, growth gradually becomes vigorous, and 20-25°C is the period of vigorous growth for Gastrodia elata. When it exceeds 30°C, the growth of Armillaria mellea is inhibited, and when it falls below 15°C in early winter, Gastrodia elata stops growing and enters dormancy.

② Humidity: Gastrodia elata is suited to areas with annual rainfall of about 1000 mm and relative humidity of about 80%. The rainy and humid climatic conditions from June to August are most suitable for the growth of Gastrodia elata. If there is prolonged rain without clearing, Gastrodia elata instead suffers harm from Armillaria mellea and is prone to rotting. Therefore, preventing waterlogging is more important than preventing drought.

③ Vegetation selection: Gastrodia elata is suited to growing in mountainous mixed forests or mixed coniferous and broad-leaved forest areas. Associated plants include bamboo, Oriental white oak, chestnut, water elder tree, wild cherry, birch, Chinese gall and other tree species, as well as ferns and mosses. Old tree stumps, fallen branches and leaves, and bark fragments, once Armillaria mellea has grown on them, are the best nutrient source for Gastrodia elata. At the same time, these plants also create good soil conditions and a shaded, humid ecological environment for the symbiosis between Gastrodia elata and Armillaria mellea, which is beneficial to the growth of Gastrodia elata. However, in years with prolonged drought, the soil moisture in the forest is all absorbed by the dense tree roots, so attention should be paid to artificial watering.

3. Cultivation methods

① Fungus-wood companion planting method: Transport the fungus-wood inoculated with Armillaria mellea to the selected cultivation site, loosen the surface soil layer, and level the bottom layer of humus soil (about 30 cm deep). Spread a layer of fallen branches and leaves on top, and place the fungus-wood in the pit along the slope, with a spacing of about 3 cm between two pieces of fungus-wood. After the fungus-wood is arranged, fill the space between the two pieces of fungus-wood with humus soil, broken branches and leaves and other filler. When half of the fungus-wood is buried, level the filling soil between the gaps, place the seed tubers against the gaps on both sides of the fungus-wood, with each seed tuber about 10-15 cm apart. Because the fungal strands are dense at both ends of the fungus-wood, place one at each end of the fungus-wood. Then spread leaves and humus soil until level, and plant the second layer in the same order. After planting, cover with 6-10 cm of humus soil, then cover with dead leaves and weeds, and dig a drainage ditch on the upper side.

② Fungus-wood plus new-wood cultivation method: The earlier steps of this method are the same as the above method. When arranging the fungus-wood in the pit, place one piece of fungus-wood and one piece of fresh wood in sequence. After filling the gaps level with humus soil, place the Gastrodia elata seeds beside the fungus-wood bearing Armillaria mellea. The other methods are the same as the companion planting method. When the Armillaria mellea on the fungus-wood establishes a nutritional relationship with the seed tubers, the Armillaria mellea also parasitizes the fresh wood at the same time. When the nutrients of the original fungus-wood are exhausted, the new wood can already provide nutrients for Armillaria mellea, thereby ensuring the growth of Gastrodia elata.

4. Management after cultivation:

① Drought prevention: The growth and reproduction of both Gastrodia elata and Armillaria mellea require sufficient soil moisture. During prolonged drought, when soil moisture is insufficient, water promptly and cover with grass to retain moisture. Drought can cause a large number of new young buds of Gastrodia elata to die.

② Waterlogging prevention: Too much rain, soil compaction and poor aeration will lead to the death of Armillaria mellea from lack of oxygen and the rotting of Gastrodia elata tubers.

③ Pest prevention: Prevent trampling by people and livestock and harm from rats, ants, diseases and insect pests, but when using pesticides, read the instructions and be sure not to harm the reproduction and growth of Armillaria mellea.