In the early spring, when greenhouses are used to grow vegetable seedlings, they are prone to frost damage in cold weather and measures should be actively taken to prevent freezing. Increase lighting In order to make the seedlings shine more in the sunlight, we should try to expose the coverings such as the cover grass and weeds in the temperature range that can maintain normal growth as early as possible. Even if it is overcast on cloudy days and rainy days, it is better to use high light transmittance. Non-drip or dust-proof film, often keep the film surface clean. Control humidity The humidity in the shed is too large, the water content in the seedlings is too high, and the concentration of the cell fluid is low, which is prone to frost damage. Due to the lower temperature in early spring and the weaker light, the humidity in the shed is too high to induce the disease. In this regard, nursery greenhouses must strictly control the number of watering and watering, when the humidity is too high to enhance ventilation. Ventilation should be carried out at high temperatures around noon to prevent cold winds from blowing directly onto the seedlings to cause freezing damage. Enhanced coverage The outdoor part of the night shed shall cover insulation materials such as cotton quilts and grass rakes, and keep the coverings in a dry state. The interior of the shed shall be insulated by multi-layer covering methods such as hanging a two-layer film, fastening a small arch shed, etc. In the north of the greenhouse, straw can be used as a windbreak to block wind and cold. Scientific fertilization Do not apply nitrogen fertilizer to avoid reducing the cold resistance of seedlings. Potassium fertilizer can increase the cold resistance of seedlings. The application of sweet and sour liquid to the seedlings can increase the sugar content and hardness of the leaf meat, and can also improve the cold resistance. Youth Biotech CO,. Ltd. , https://www.youtherb.com