In winter and spring season, low light stress is a common adverse condition in the production of solar greenhouses. It often occurs with low temperatures, directly affecting the growth, development, yield, and quality of vegetables. Under normal circumstances, the average light transmittance of plastic greenhouses is about 50%. When it comes to overcast snow days, indoor lighting conditions are even worse. Low light is one of the main limiting factors for the production of solar greenhouses in winter and spring. For planting fruits and vegetables, weak sunlight in the solar greenhouse in winter will seriously affect the growth and yield of vegetables. Therefore, in winter production, increasing lighting and improving lighting conditions are an important technical measure for growing good vegetables. Here are some countermeasures to deal with the weak light conditions in the facility: 1. Long-lived drip film with high light transmittance is the ideal material for protective coverage. First, the drip effect is good, and the light transmittance is better than the ordinary film. Increased by about 7%; Second, good insulation performance, temperature is 1~2°C higher than that of general greenhouse covered by thin film, vegetables can be raised in the morning; Third, strong anti-aging, high mechanical strength, and longer life than ordinary polyethylene film 1 More than times. Second, often keep the film clean Every day, insist on using tools such as dustpan cleaning dust outside the shed film, grass clippings, etc. can significantly increase the light, if the inner wall with water droplets, can be released through the air or with a cloth to remove. Water droplets and dust on the shed film have a great influence on the lighting conditions in the shed. According to observations, a layer of water droplets is attached to the film, which can reduce the light transmittance by 20% to 30%. Remove snow in time after snow, in order to increase the amount of light. III. Covering the straw and paper at the right time Under the premise of ensuring the temperature, the cover should be covered as soon as possible. On cloudy days, under the premise of ensuring that the vegetable crops in the shed are not affected by the low temperature, grass curtains should also be opened to increase the scattering of light indoors. Fourth, in the greenhouse wall hanging reflective film (aluminum film) Before and after heavy snowfall, hanging the reflective film in the sun wall behind the ground 0.3m above ground, can significantly increase the amount of light in the northern half of the greenhouse, and Increase the effect of ground temperature. According to observations, it is generally possible to increase the light intensity near the ground by 40% to 43%, increase the temperature in the shed by 3 to 4°C, increase the ground temperature by 5° at 1.0°C, and increase the ground temperature by 10°C at 10cm. At the same time can reduce the incidence of disease. Fifth, the laying of silver gray film on the ground This method has a good pre-lightening effect. Sixth, artificial light commonly used greenhouse artificial light incandescent lamps, fluorescent lamps, high pressure mercury lamps, metal halide lamps and ammonia lamps. Due to the high cost, artificial fill light should not be promoted in large areas, and it can be used as an emergency measure to improve lighting conditions in the shed. VII. Selection of special greenhouses resistant to low light The varieties of cucumbers with low light resistance currently include Beijing 101, Nongda 12 and other varieties. Pepper has Xiangyan No. 1 and Xiangyan No. 2 and other varieties. Eggplant has Liaoqie No. 7 and so on. VIII. Appropriately sparsely cultivated by adopting a wide-narrow line in the north-south direction, arranging vines in a timely manner, pruning and pruning, removing old leaves, and diseased leaves. Nine, temperature control in cloudy days, day and night temperature management should be 5 ~ 7 °C lower than sunny. X. Moisture management Under weak light conditions, it is important to control the number of waterings and the amount of watering to ensure the preservation of water. The watering must be carried out on a sunny morning. Especially during the seedling stage, water is generally not watered if it is not particularly dry. XI. Use of Growth Regulators Fruit and vegetable vegetables are prone to flowering and fruit drop under low light stress, and can be sprayed on young fruit and inflorescence with 6-BA plant growth regulators. Source of information: National Agricultural Information Engineering Technology Research Center