1. Cover the seedbed soil with black plastic film in high temperature weather in summer, so that the temperature generally reaches 40 degrees Celsius, and bacteria and eggs die. Completely eliminate plant residues of pests and diseases, and cut off the transmission route of pests and diseases.
2. The main function of plastic film is to keep warm and moisturize. Covering with plastic film can effectively prevent soil erosion, keep moisture, and keep purple cabbage moss from freezing in cold weather, thus keeping warm.