If the humidity in the greenhouse is high, the germs will spread rapidly and the disease will be serious, which will be detrimental to the growth of the crop. The principle of humidity control should be "head wet and dry." In order to reduce the humidity in the greenhouse, the following measures can be taken: 1. Ventilation and ventilation will eliminate moisture, but the contradiction between heat preservation and dehumidification should be handled properly, so as not to lose sight of one another. 2. The mulching of the mulching film can greatly reduce the evaporation of water on the ground, and can reduce the number of irrigating, thereby reducing the air humidity. 3. Using drip irrigation or drip irrigation Drip irrigation and percolation irrigation are used in greenhouses. In addition to saving water, labor, fertilizer, and medicine, preventing soil compaction and reducing the temperature of the soil, it is more important to effectively reduce watering. This caused a significant increase in air humidity. 4. The drip irrigation under the drip film under the membrane combines the common advantages of mulching and drip irrigation, and is the most effective measure to reduce the humidity in the greenhouse. The method is to raise the ridge from the ground, then put the drip irrigation pipe in the center of the high ridge, and then cover the mulch. 5. Dust and smog method The air humidity in the greenhouse is inherently large, and the use of conventional spray methods increases the humidity. The use of dust and smog method can avoid increasing the air humidity due to spraying and improve the control effect. 6, high temperature and humidity in the morning after the exposing, under normal circumstances do not let the wind, in the premise of not harming the cultivation of crops, should try to increase the temperature (such as cucumber, can let the temperature rise to 32 °C). As the temperature rises, the humidity gradually decreases. When the temperature rises to the highest value of the suitable temperature required for the cultivation of the crop, exhalation begins. 7, the use of wetlands in the cultivation of wetlands when the temperature is high, the shallow surface, accelerate surface water evaporation, prevent deep water up. 8. Hanging reflective screens Hanging reflective screens can increase the ground temperature and air temperature by about 2°C. Because the relative humidity decreases as the temperature rises, the hanging light curtain also has a certain degree of dehumidification.