What are the requirements of douban on environmental conditions?

(1) temperature. Watercress likes cold, is afraid of cold, is afraid of heat, has strong cold resistance and can endure frost in a short time. The optimum temperature for growth and development is 15 ~ 25℃, with 20℃ being the best. When the temperature is lower than 15℃, the growth is slow. When the temperature exceeds 25℃, although the plant grows fast, the plant is thin, the leaves are yellow, and many adventitious roots grow on the nodes, resulting in poor quality.

(2) lighting. Douban needs strong light, and it is best to have 7-8 hours of light every day. In rainy days, when plants are shaded, the light is insufficient, the main stem is long, the leaves are thin and yellow, and the quality is degraded.

(3) moisture. Watercress likes wet conditions, which can be planted in ditches or hydroponics (nutrient solution soilless culture). But in summer, the temperature is high and the ventilation is not good, which is easy to produce rotten seedlings.

(4) soil. Watercress has wide adaptability to soil, loam, sandy loam and clay can be cultivated, but fertile neutral or slightly alkaline clay loam or loam is the best. Suitable for paddy field planting and dry land planting, but always keep the soil moist.