‌Controlling the light in the greenhouse can be done in the following ways:

‌Reasonable layout‌: When planting different types of vegetables in the greenhouse, the principle of "high in the north and low in the south" should be followed to make the plants staggered and orderly, and minimize mutual shading. When transplanting the same type of vegetables, strive to make the seedlings of the same size, so that the plants grow neatly and reduce inter-plant shading. It is best to plant in the north-south direction so that they can receive as much sunlight as possible.

‌Keep the greenhouse film clean‌: Water droplets, dust and other debris on the greenhouse film will reduce the light transmittance by about 30%. After the new film is used for 2 days, 10 days, and 15 days, the light in the greenhouse will be weakened by 14%, 25%, and 28% respectively. Therefore, it is necessary to frequently clean and rinse the dust, dirt and water droplets on the greenhouse surface to keep the film surface clean to increase the transparency of the greenhouse film. Snow should also be cleared in time on snowy days.

‌Choose drip-free film‌: Several surfactants are added to the drip-free film during the production process, which greatly weakens the affinity between water molecules and the film, and water droplets flow into the ground along the film surface without producing water droplets. Choosing drip-free film to cover the greenhouse can increase the light intensity in the greenhouse and increase the greenhouse temperature‌.

‌Scientific curtain lifting‌: When the weather is sunny, while doing a good job of insulation, appropriately remove the insulation straw curtain and delay the curtain to extend the lighting time and increase the amount of light. Generally, the curtain is lifted 0.5-1 hour after the sun comes out, and the curtain is covered half an hour before the sun sets. The curtain should also be lifted appropriately on rainy days to make full use of the sun's scattered light‌.

‌Set up a reflective curtain‌: In the case of insufficient light, a 2-meter-wide and 3-meter-long aluminum film reflective curtain can be hung on the north side of the greenhouse to make it vertical to the ground, which can increase the ground light by about 40% and increase the greenhouse temperature by 3℃-4℃. In addition, laying a silver-gray ground film on the ground can also increase the light intensity of the plants‌.

‌Timely pruning‌: Timely pruning, pruning, tying vines, and removing old leaves are beneficial to ventilation and light transmission in the greenhouse‌.

‌Improving greenhouse structure‌: Reasonable selection of greenhouse building materials and greenhouse angles, and appropriate increase in greenhouse height can also improve the lighting conditions in the greenhouse. For plastic greenhouses mainly cultivated in spring and autumn, the greenhouse angle can be smaller (about 15°), and the winter requires a larger greenhouse angle (about 25°).

Through these methods, the light in the greenhouse can be effectively controlled, the photosynthesis efficiency of plants can be improved, and the yield and quality of crops can be improved.