In constructing a greenhouse, it is very important to set up a cold-proof ditch. However, at present, most greenhouses do not have a cold-proof ditch, or the cold-proof ditch is not reasonable. Some of the cold-proof ditch is set outside the shed, and some dig a trench 30 cm wide and 40 cm deep at the front of the shed, and fill in the grass. As a result, there is no management after the setting, and anyone is free to step on and lose the cold-proof effect.
1 The cold-proof ditch should be set as a cold storage temperature adjustment ditch, which should be set in the four laps of the entire shed. First of all, the cutting-edge cold-proof ditch should not be set outside the shed, but should be set in the front of the shed, digging a groove 30-40 cm wide and 40 cm deep, and then laying the old film on the bottom of the ditch, then 90 cm wide. The double-sided film (a barrel-shaped plastic agricultural film), from east to west, is equivalent to a tube in which the film is filled with water.
2 During the daytime, the temperature at the front of the greenhouse is 2°C~3°C higher than that in the latter half of the greenhouse and the middle, while the temperature at the front of the greenhouse is 3°C lower than the latter half, and the vegetables are prone to freeze damage. The tube is filled with water, which absorbs heat during the day and does not allow the temperature in the front of the shed to be too high. In the evening, the water in the pipe will dissipate the heat accumulated during the day, which will significantly increase the temperature in the first half. The temperature of the entire shed will increase.
3 Another advantage is that when watering in the future, the water in the pipe will be poured into the ground. The warm water will be poured and the ground temperature will not be lowered. The cold-proof ditch should be dug in front of this thin-film tube, covered with thick grass, and finally covered with a large greenhouse film, and press the soil on the outside of the film. After this treatment, the water flowing from the film on the greenhouse will flow down to the grass, after the grass is damp. Fermentation will release carbon dioxide, which will not only provide insulation but also provide carbon dioxide needed for photosynthesis in plants.
4 The biggest advantage of this treatment is that it solves the problem of partial soil moisture in the front part. The original greenhouse was covered with the front membrane directly on the ground. As a result, the water flowing down from the membrane was accumulated in the front soil. Causes the front soil to be too wet, and finally causes the diseases such as downy mildew and gray mold in the front crops. If the disease spreads further, it will infect the entire greenhouse.
5 The gables and the rear half of the shed should also be provided with a cold-proof ditch, 20 cm wide and 30 cm deep, filled with wheat bran or wheat straw, and stepping on solid porcelain without having to cover the film. These grasses can not only prevent the heat from being transmitted, but also absorb moisture, reduce the humidity and reduce the occurrence of diseases. After absorbing the tide, these grasses can also ferment, release carbon dioxide, and solve the problem of insufficient carbon dioxide in the shed. Therefore, the cold-proof ditch must be located in the shed. Do not set it outside the shed. Gables and cutting edges must be set.
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