Only after the greenhouse covering materials are installed, the greenhouse becomes “effective”. Air temperature, humidity, carbon dioxide content, soil temperature and light determine the growth environment of the greenhouse and plants. In order to keep the solar radiation entering through the covering materials and the heat lost in a balanced state, growers can use environmental control systems (heating, ventilation and cooling) to improve the greenhouse environment according to changes in the outdoor environment to meet the needs of plant growth.

Greenhouse covering materials directly affect the amount (intensity) and type (diffuse/direct light ratio and spectral band) of solar energy received by plants in the greenhouse. Solar energy affects its growth through the physiological reactions of plants, such as the movement of water in the plant body (transpiration), the absorption of solar energy (photosynthesis), etc. Solar energy can also affect leaf surface temperature, which is controlled by leaf surface transpiration. After the plant leaves release steam, the water vapor content (air humidity) in the greenhouse is increased. The water vapor in the air can be removed by the ventilation system for indoor and outdoor air exchange, or condensed on the low-temperature surface of the greenhouse structure, mainly on the greenhouse covering materials.

No greenhouse covering material is perfect. Each covering material affects the climate conditions in the greenhouse with its unique characteristics, and the climate conditions in the greenhouse determine the final production performance and output of the plants.