What are the common anti-freezing methods of vegetables without heating in the greenhouse?

Now it is the cold winter season, and it is a survival test for many kinds of vegetables, so if it is a greenhouse, how to adopt some commonly used and effective methods to ensure the normal growth of vegetables to a certain extent without heating? What are the common anti-freezing methods of vegetables without heating in the greenhouse?

1. Multilayer film covering

The thermal insulation performance of the first greenhouse film is poor, and freezing damage will occur when the external temperature is low, that is, about 0 ℃ in the greenhouse. Therefore, multi-layer film is needed to ensure the temperature in the shed. That is, to achieve "three films and one curtain" cover, that is, cover the greenhouse film, small greenhouse film, plastic film, and then cover the greenhouse with grass curtains, when the external temperature drops to-5 ℃, freezing damage generally will not occur in the greenhouse.

2. Preparation of thermal soil

Breathable fertilizers such as chicken manure, hot organic fertilizer, cow manure and other breathable fertilizers are used into hot soil, that is, when the soil is mature, 20% is taken and 60% is mixed with fine dry soil. The nutritious soil has good heat absorption and heat generation performance, so that the vegetable seedling growth environment is good, the root growth number is large and long, the absorption function is strong, the growing vegetables are strong, and the natural cold resistance is strong.

3. Controlled application of nitrogen fertilizer

Properly reduce the amount of nitrogen fertilizer in the seedling stage, must not be partial application of chemical nitrogen fertilizer, so as to avoid poor cold resistance of vegetables. It is advisable to top up early to promote the growth of vegetable seedlings. Quick-acting nitrogen fertilizer can not be applied before low temperature, but phosphorus and potassium fertilizer should be applied once to enhance cold resistance. Weak light in winter, poor fertilizer absorption capacity of vegetables, foliar spraying of photosynthetic micro-fertilizer can prevent and cure the deficiency caused by insufficient absorption of nutrients by roots, and at the same time, growth hormones should be used less or not to prevent tender growth and reduce cold resistance.

4. Replenish carbon

The vegetables cultivated in the greenhouse can absorb the carbon dioxide produced by plant respiration and soil microbial decomposition at night one hour after sunrise, and then become carbon hungry. Therefore, when the temperature is high in sunny days, the greenhouse film can be opened and closed and put into the outside carbon dioxide to improve the cold resistance and yield of vegetables. when the temperature is low, the greenhouse is closed, and carbon dioxide is artificially replenished in winter, which can improve cold resistance and increase production.

5. Shallow ploughing and heat preservation

Vegetable land surface hardening, hot air into the ploughing layer is limited during the day, heat storage will be reduced, coupled with large and deep cracks, poor soil aggregate structure, easy to dissipate heat in the first half of the night, low room temperature in the second half of the night, easy to cause chilling damage. If the greenhouse soil is shallow and medium-ploughed, it can play the role of breaking consolidation and filling cracks, which can not only control groundwater transpiration to take away heat, but also preserve soil moisture and heat preservation, prevent cold and protect seedlings.

6. Pour enough water to prevent frost

The freezing injury of vegetables in winter is mostly caused by lack of water. Because the specific heat of water is higher than that of air and dissipates heat slowly, if the soil water content is moderate, the pore cracks in the tillage layer are dense, and the root system is not suspended, the soil thermal insulation can be improved and the root system will not be damaged by freezing. Therefore, the effect of anti-freezing is good if the greenhouse vegetables are filled with enough water before winter or in winter.

7. Raising seedlings in nutrition bowl

The black plastic nutrition bowl was used to raise seedlings, heat absorption and root protection during the day. When the external air temperature was below zero, the temperature in the shed was about 5 ℃, while the temperature in the nutrition bowl was about 8: 10 ℃, the vegetable seedlings could grow slowly and not be damaged by freezing.

8. Root irrigation with rooting element

For greenhouse vegetables that pass the winter, the root system can be increased by about 60% and the root depth by about 25% after the use of rooting element. With well-developed roots and strong absorptive capacity, vegetable seedlings will not suffer frostbite due to poor cold resistance due to lack of water and elements.

In addition, if there are conditions, it is best to use galvanized steel pipe greenhouse. It is best to use drip-free film for greenhouse film and polyethylene film for ordinary film; it can whitening building materials and walls, which can increase reflected light and prolong service life; and appropriately increase the height of greenhouse can also improve the lighting conditions in the greenhouse.