What environmental conditions should be noted when growing American ginseng?
American ginsengIt is native to southeastern Canada and the northeastern United States, growing in broadleaf forests in low mountain areas at an altitude of 100-500 m. In this region, the changes between cold and heat are not great, and rainfall is fairly evenly distributed across the months, with the characteristics of a temperate maritime climate. Having long grown wild in this environment, American ginseng has developed growth characteristics of fearing sunlight, preferring shade and moisture, fearing severe cold, and preferring mild coolness. Therefore, during the cultivation of American ginseng, attention should be paid to the influence of environmental conditions on it and reasonable regulation should be applied.
I. Temperature
After the embryo of American ginseng has undergone morphological maturation and the seed has split, it still needs to go through 3.5-4 months at a temperature of about 5°C to complete physiological maturation. The rhizome bud, on the other hand, needs more than 2 months at a temperature of about 5°C to break dormancy and acquire the physiological conditions for emergence. Generally, American ginseng begins to emerge only when the soil temperature stabilizes above 10°C, and 15-18°C is most suitable for seedling-stage growth; during the flowering period, an average temperature above 20°C is most suitable. American ginseng is not tolerant of severe cold. At -12°C, one-year-old rhizomes suffer freeze damage, and at -17°C the main root suffers freeze damage. Alternating high and low temperatures can cause freeze damage to ginseng roots more than continuous low temperatures, so in northern regions the seedbed surface for growing American ginseng must be covered with cold-protection materials in winter.
II. Light
Because American ginseng has long grown wild under broadleaf forests, where light is insufficient and conditions are relatively shaded and moist, it has developed an adaptation to shade and moisture. It is particularly sensitive to light, most afraid of direct strong light, and prefers scattered light and slanted light, belonging to shade plants. Generally, in the young stage (one- and two-year-old plants) it needs greater shading, while in the adult stage (three- and four-year-old plants) light should be appropriately increased. In cooler growing seasons (such as spring and autumn) and in cooler regions (such as the north or high mountain areas), light intensity may be appropriately increased. In hotter growing seasons (such as summer) and in hotter regions (such as the south or low mountain areas), shading should be appropriately increased. Light intensity is generally controlled between 10-30%, and may even be controlled below 10%. In the adult stage and in cooler seasons and regions, light intensity can be controlled between 20-30%. The suitable light intensity for cultivated American ginseng is affected not only by the age of the seedlings and different growth and development stages, but also greatly by climate changes. Therefore, light intensity should be flexibly adjusted according to specific conditions.
III. Water
American ginseng is relatively sensitive to water and has strict requirements for it. If water is insufficient, American ginseng grows poorly, yields are low, the root epidermis easily turns yellow or the fibrous roots burn, and in severe cases the entire plant withers. Because the root system of American ginseng is not well developed, with many fibrous roots distributed in the plow layer and few root hairs, it is not drought-tolerant. This requires that sandy soils with poor water retention be promptly supplied with water during dry seasons, but water should not reach a saturated state. If there is too much water, root diseases are easily caused, and in severe cases patches of plants may die. Therefore, in the cultivation and management of American ginseng, water management is very important and will affect both the yield and the quality of American ginseng.
Different growth stages of American ginseng have different water requirements. Generally, from the seedling stage to the stage when aboveground growth has become established, sufficient water supply is needed because of increased growth. This growth and development stage of American ginseng also coincides with the spring drought period, so it should be watered frequently to keep the seedbed soil moist. July and August are the rainy season, so watering is generally not needed. In addition, if the soil water content is too high during overwintering, it can cause freeze damage to the ginseng roots and bud scales, which needs to be guarded against.
IV. Soil and Fertilizer
American ginseng is suitable for planting in slightly acidic soil with high humus content, relatively fertile, soft texture, good water and fertilizer retention, good aeration, good granular structure, no hardening, and a pH of 5.5-6.5. Sandy soil, saline-alkali land, and places with poor drainage are all unfavorable for the growth of American ginseng and are prone to disease.
American ginseng plants are not large, grow slowly, and have limited growth, so their fertilizer requirements are only moderate. If the soil is fertile and loose, there is no need to apply more fertilizer when planting American ginseng. If American ginseng is cultivated in farmland soil, necessary soil improvement should be carried out. Where organic matter content is low, more organic fertilizer should be applied as base fertilizer, and where the soil is relatively clayey, sand may be mixed in. During the growth period of American ginseng, phosphorus and potassium fertilizer and a small amount of nitrogen fertilizer should be appropriately applied as topdressing. Remember one thing: nitrogen fertilizer should not be applied too much, otherwise it will cause excessive vegetative growth of the plants and reduce their resistance.