The technology of growing fruits and vegetables in greenhouse is mature gradually, which can provide the growing period and increase the yield in the season that is not suitable for plant growth. The investment cost of vegetable greenhouse construction mainly consists of two parts: the cost of greenhouse construction and the cost of daily maintenance. General vegetable greenhouses will use steel-based structure skeleton, which of its management skills?

What's more, the lighting, temperature, humidity, air composition, soil moisture and salt all need to be controlled. The illumination depends on the solar radiation intensity ode the shed, the optical characteristics of the covering material and the pollution degree. The light transmittance of the new plastic film is 80% 85% , the old film which is polluted by dust and mud is often less than 40% . So in the management of the greenhouse, to try to avoid and eliminate the factors that weaken the lighting in the greenhouse. The diurnal variation trend of air temperature in greenhouse was the same as that in open field, but the diurnal variation was larger. So in order to reduce heat loss in winter, improve air temperature and soil temperature, plastic film cover as tight as possible. Water bags can also be placed in the shed (plastic bags filled with water) , making use of the characteristics of high specific heat of water, water bags absorb a lot of solar energy during the day, and into heat storage, released gradually at night, can increase the temperature of the shed.

Third: during the day, under the condition of greenhouse ventilation, the relative humidity of the air in the greenhouse is 70% ? 80% . Overcast and rainy days or after irrigation can reach more than 90% . The relative humidity of the air in the shed decreases with the increase of temperature, usually 100% at night. When the moist air is cooled in the shed, it condenses into a water film or drops which adhere to the inner surface of the film or the plant. The excessive humidity in greenhouse directly affects the photosynthesis of vegetables and the absorption of mineral nutrition, so ventilation should be carried out to accelerate the exchange of high humidity air in greenhouse with low humidity air ode.