In the shed area of ​​Nancun Town, Pingdu City, Shandong Province, holes are left on the back wall of almost every greenhouse. This has become a major feature of the structure of vegetable greenhouses in Pingdu City. These holes are mostly left at a height of 1 meter above the ground. They are usually every 3 meters and each have a diameter of about 20 centimeters. A greenhouse of one acre usually has more than 20 holes on the back wall. The local vegetable grower said: “You don’t look at the uselessness of these holes, but in the summer, it’s very useful. Everyone knows that in the summer when the temperature is high, even if the vents on the roofs and sheds are fully open, sometimes Can not reduce the temperature, although the effect is better with the shade net cooling, but the disadvantage is that while reducing the temperature, but also reduces the light transmittance, and we use the hole in the back wall of the greenhouse ventilation method, the cooling effect is very significant. It is in the hot weather that the ventilation holes in the front wall and the front wall of the shed are fully opened, which can conveculate the air in the shed and quickly reduce the temperature inside the shed so as to prevent greenhouse vegetables from being exposed to high temperature in summer. Sometimes, an inconspicuous method can bring about high efficiency. When you build a greenhouse, when you build a greenhouse, you can leave a few holes on the back wall to try. Urine Reagent Test Strips,Urinalysis Reagent Test Strip,Ketosis Lose Fat Diabetics,Clinical Urine Test Strips Changchun Medicon Technology Development Co., Ltd , https://www.teststrip.pl