Prevention and control of frost injury of vegetables in greenhouse on cloudy and rainy days this winter

Recently, under the influence of cold air, there have been a wide range of continuous freezing rain and snow days in the north, which seriously affected vegetable production, especially greenhouse vegetable seedlings. In order to do a good job in greenhouse vegetable anti-freezing work, the following measures can be taken to ensure the safety of vegetables through the winter.

Greenhouse vegetables are covered with anti-freezing

First, strengthen coverage:

Buckle the small arch shed in the vegetable greenhouse, use the thin bamboo pole as the arch frame, cover the film at night, cover the grass grass on the film, and cover the plastic film in the greenhouse to increase the temperature and keep the moisture. Plastic film is used as an apron at the bottom of the shed, which can significantly reduce the invasion of cold air at the bottom; at the same time, plug gaps everywhere and reduce heat dissipation as much as possible. Wind barriers are made of straw to the north of the greenhouse to keep out the wind and cold.

Second, temporary heating:

Freezing injury may occur when the temperature in the greenhouse is lower than 15 ℃ during the day and 5 ℃ at night. Temporary heating measures can be taken at night to replenish heat manually. Putting several briquettes in the shed can increase the temperature in the shed. But should pay attention to prevent carbon dioxide poisoning, adding briquettes and coal stove, the greenhouse should be ventilated first, and then into the people.

Third, strengthen the management of fertilizer and water:

Irrigation in the greenhouse to improve the soil and air humidity in the greenhouse has a certain cold-proof effect. After irrigation, vegetables are not damaged by freezing at-4 ℃. The mixture of rice vinegar, sugar and calcium superphosphate was mixed into a 300-fold solution and sprayed on the leaf surface to increase the sugar content and hardness of the mesophyll and improve the cold resistance. Pour dilute dung water in the greenhouse to make the soil not easy to freeze and achieve the purpose of seedling protection and cold protection.

Fourth, strengthen disease prevention and control:

Vegetables are vulnerable to diseases and insect pests after being frozen, so it is necessary to spray chlorothalonil and other fungicides in time to prevent and control diseases and insect pests. Scatter plant ash, equal to cover vegetables, can play the role of anti-freezing and disease prevention. At the same time, put fumigant in the shed to burn to kill the germs in the shed.

5. Management of frozen vegetables:

1. Irrigation and heat preservation: irrigation can increase the soil heat capacity in the greenhouse, prevent the soil temperature from falling, stabilize the temperature, help the air temperature rise steadily, and restore the function of the frozen tissue of vegetables.

2. Ventilation and cooling: after the greenhouse vegetables are frozen, the shed can not be closed immediately, but can only be cooled by ventilation to make the temperature in the shed rise slowly and avoid the sharp rise in temperature and lead to the necrosis of frozen tissues of vegetables.

3. Artificial water spraying: water spraying can increase the air temperature in the greenhouse, stabilize the greenhouse temperature, inhibit the evaporation of water from the frozen tissue of vegetables, and promote the tissue to absorb water.

4. Cut off dead branches: cut off frozen branches and leaves in time to avoid mildew and disease of frozen tissue.

5. Set up a shed to shade the sun: build a sunshade in the shed to prevent direct sunlight from frozen vegetables, so as not to lose vitality due to tissue dehydration and shrinkage.

6. Supplementary application of fertilizer: after slow seedling of frozen tissue, quick-acting fertilizer should be applied in time. Foliar can be sprayed with 2% urea solution and 0.2% potassium dioxin phosphate solution.

7, the use of hormones: the growth of vegetables is slow after freezing, and the new branches and leaves are delayed. Exogenous plant hormones can be sprayed to promote growth and speed up the recovery of the body.