Both low temperature and high humidity, and high temperature and high humidity, are major causes of disease occurrence and spread in Greenhouse. Therefore, controlling greenhouse humidity is a crucial aspect of greenhouse cultivation techniques.
Ventilation is a fundamental method for dehumidifying Greenhouse.
Ventilation must be carried out during high temperatures; otherwise, it will cause a drop in the greenhouse temperature. The most effective time for ventilation during the day is midday, as the humidity difference between inside and outside the greenhouse is greater at this time, making it easier for moisture to escape.
At other times, ventilation time should be extended as much as possible while maintaining the required temperature. If the temperature drops too quickly during ventilation, the vents should be closed promptly to prevent a sudden drop in temperature from harming the vegetables.
Use plastic film mulching to reduce humidity. Mulching reduces the evaporation of surface moisture into the greenhouse, which is an important measure to lower the humidity inside. Use dust or fumigation methods for pesticide application to control humidity. Using dust or fumigation methods for pesticide application avoids increasing air humidity due to spraying, improving the control effect.
Cultivation for dehumidification. By interrupting soil capillaries, it prevents capillary water from rising to the surface, thus preventing excessive evaporation of soil moisture. Natural moisture absorption.
Laying a layer of straw, wheat straw, or quicklime between rows, or sprinkling a layer of wood ash, can absorb water vapor or mist, thus reducing humidity. Heating and dehumidifying. When the temperature inside the greenhouse is low, the relative humidity can be reduced by increasing the temperature, while also meeting the temperature requirements of the vegetables.
Proper watering and humidity control. Watering is the main factor leading to increased humidity inside the greenhouse. In winter and spring, choose sunny days for furrow irrigation or watering each plant separately. For greenhouses covered with plastic film, drip irrigation under the film can be used. Strictly control the amount of water. After watering, ventilate appropriately and loosen the soil promptly by hoeing to reduce air humidity.