Frost will hurt plants if the greenhouse is not closed at night. If you don't close the greenhouse at night, it will cause the greenhouse to be unable to keep warm, and the plants will freeze to death if the temperature is too low. Greenhouse is a common thermal insulation facility in agriculture, which has a good effect on vegetable production and cutting seedling in early spring. It consists of skeleton, bracket and agricultural film. Greenhouse can not only resist natural disasters, prevent cold and keep warm, protect crops from drought and flood, but also cultivate early and late, extend the growth period of crops, achieve the purpose of early maturity, late maturity, and increase production and stability, which is very popular among producers.