The light condition in plastic greenhouse directly affects the growth, yield and quality of vegetables. In winter and spring, the sunshine time is short, the sunshine intensity is weak, and the cloudy, snowy, rainy and foggy weather increases, which has a great influence on the growth of greenhouse vegetables. Therefore, it is necessary to take some effective measures to improve the lighting conditions in the greenhouse, so as to facilitate the production of greenhouse vegetables.

Orientation, structure and materials of the greenhouse: the greenhouse should be built in the leeward and sunny place, facing south or grabbing the sun or shading, so as to receive the sun to the maximum in winter; Improve the shed structure and the way of framing film, minimize the number of arches, columns and tie rods in the shed, and choose new materials that are durable and can reduce shading to reduce shading area; The building materials and walls in the shed are painted white to increase the reflected light. Try to use drip-free film as shed film, which can increase the input of light and improve the yield and quality of vegetables.

Reasonable collocation of vegetables planted in greenhouse: When planting different kinds of vegetables in greenhouse, reasonable collocation should be carried out according to the principle of "high in the north and low in the south", and vegetables should be staggered according to plant height to minimize shading between plants.

Other production management measures: clean the inside and outside of the shed film frequently, especially after it snows, and clean the snow on the top of the shed in time to keep the transparent surface clean, but be careful not to damage the shed film when cleaning; Uncover the straw mat in time, cover the straw mat as late as possible to extend the illumination time under the premise of ensuring the minimum temperature above the limit temperature; Cover the greenhouse with plastic film to increase the scattered light in near-earth space and improve the lighting conditions in the facility; Setting aluminum alloy reflective curtain or hanging silver reflective film at the weak light on the north side of vegetable greenhouse can increase the light on the north side of greenhouse by 20 ~ 40%; It is also an effective measure to fill the greenhouse with artificial light, especially in the case of fog for several days or long rainy weather in winter. Installing incandescent lamps, fluorescent lamps and high-pressure mercury lamps is also an effective measure. To increase the light. Generally, the greenhouse can fill up the light for 4 to 5 hours every day. In addition, it is necessary to deal with old leaves, diseased leaves and excessive branches on vegetable plants in time to increase the light between plants.