How to prevent high temperature in greenhouse vegetables in summer?

There are many hot weather in summer. If effective measures are not taken to reduce the temperature in the greenhouse, E79FA5E98193E59E7ad9431333534136, vegetables will easily flourish, wilt, get sunburned and drop flowers and fruits at high temperature. In general, the temperature of solanaceous vegetables should be controlled at 25℃~30℃ during the day and at 15℃ ~ 16℃ at night. The temperature of melons and vegetables is controlled at 26℃~32℃ during the day and at 15℃~ 18℃ at night. When the temperature in the shed exceeds 35℃, a sunshade net should be set at the top of the shed to cool down. When the temperature exceeds 18℃ at night, cooling measures should be taken to widen the temperature difference between day and night and ensure the normal growth of vegetables.

First, adjust the shed film and control the temperature reasonably. For greenhouses in winter, when the minimum temperature is stable above 15℃, the grass curtain should be removed or not covered at night to avoid high temperature at night and high nutrient consumption, which will lead to poor flowering and fruit setting. As the temperature continues to rise, the ventilation volume and ventilation time should be increased against the wind. When it is difficult to control the temperature rise in the greenhouse against the wind, the front vent should be opened again, and appropriate shading and cooling measures should be taken to ensure the normal growth of crops.

For arched greenhouses, the following methods can be adopted according to the actual situation to achieve the purpose of regulating the environment in the greenhouse and benefiting the growth of vegetables: First, the top film is still made of plastic film, and the skirt film is removed. In this way, the upper membrane is used to shelter from the rain, and the lower position is ventilated. Second, the top film is still a plastic film, and the insect-proof net of the skirt film cover is removed. In this way, using the top film to cover the rain can isolate pests and prevent pests from harming vegetables in the greenhouse, but the ventilation and moisture permeability in the greenhouse are poor, and it is easy to have high temperature or high humidity. Third, on the basis of retaining the plastic top film, remove the skirt film and cover the sunshade net. This method is often used in summer vegetable production and seedling raising.