Extreme weather processes are strong, long, wide-ranging, and cause serious damage, resulting in deformation and collapse of plastic greenhouses, multi-span greenhouses, and solar greenhouses. In response to the impact of heavy snow and continuous snowy weather for many days, what adjustments should we make to the greenhouse?

1. Timely snow removal and inspection and repair of various facilities. Clear the snow in the solar greenhouse as soon as possible, carefully check the damage, and actively and quickly repair the damaged greenhouse film, film pressing line, frame, internal and external circuits, roller shutters, air vents, lighting, water pumps and other equipment. Organize forces to remove the snow around the facility park and the main access as soon as possible to prevent the melting of snow from causing water accumulation and siltation around the greenhouse. At the same time, pay attention to the safety of snow removal personnel, especially to avoid the collapse of the shed and personal injury. Further strengthen facilities and equipment to prevent more severe wind and snow again.

2. Management points for long periods of snowy weather. If the number of cloudy and snowy days exceeds 3 days, the heat preservation cover of the solar greenhouse should be uncovered in time during the day when the outside temperature is not very low; when the outside temperature is low during the day, the heat preservation cover of the solar greenhouse should also be uncovered for a short time at noon to allow the vegetables to receive some scattered light, so as to avoid the growth disorder of the vegetable plants caused by not uncovering the heat preservation cover for several consecutive days.

3. Key points for management in the early stage of clear weather. This time, the continuous cloudy and snowy weather lasted for a long time, and the greenhouse was covered for a long time. Therefore, after the weather suddenly cleared, it is necessary to take the approach of uncovering the heat preservation cover of the solar greenhouse at intervals, alternately, or gradually opening the heat preservation cover. The heat preservation cover should not be uncovered immediately to prevent the crop leaves from losing water and wilting under strong light. If the leaves are found to be wilting after uncovering the heat preservation cover, the heat preservation cover should be covered immediately, and then gradually uncovered after the plants recover, and ventilation and dehumidification should be restored in time. Normal management can be returned to normal after 1 to 2 days. After the plants adapt, potassium dihydrogen phosphate and amino acid foliar fertilizers should be appropriately applied to the leaves.

4. Strengthen field management after cloudy and snowy weather. Mainly pay attention to the management of sunlight greenhouse lighting, heat storage and insulation, crop fertilizer and water management, ventilation and dehumidification management, etc.

First, strengthen the management of greenhouse heat storage and insulation. After a heavy snowstorm, it is often accompanied by a sharp drop in temperature. In addition to maintaining and strengthening the insulation cover of the sunlight greenhouse, you can also take measures such as adding bubble film between the insulation blanket and the greenhouse film, adding simple buffer rooms or enclosures inside and outside the door, sealing the gaps in the greenhouse, surrounding the front foot with a “skirt curtain”, and hanging two curtains in the greenhouse to comprehensively improve the heat storage and cold resistance of the sunlight greenhouse. In places where conditions permit, emergency heating equipment such as heating blocks, oil or coal-fired hot air furnaces, mobile electric heating fans, and heaters should be prepared.

Second, strengthen the management of greenhouse lighting. When the temperature permits, try to uncover the insulation cover of the sunlight greenhouse as early as possible and cover it as late as possible to extend the lighting time. The time to uncover the insulation cover should be when the temperature in the greenhouse does not drop after uncovering the insulation cover; at the same time, the insulation cover should be covered in time. For solar greenhouses with good insulation performance, the insulation cover should be covered when the temperature in the solar greenhouse drops to 15-17℃ in the season when the lowest temperature at night is 0–15℃; the insulation cover should be covered when the temperature in the solar greenhouse drops to 17-19℃ in the season when the lowest temperature at night is below -15℃. Solar greenhouses with poor insulation should cover the insulation cover early. Clean the greenhouse film in time, and hang reflective curtains on the back slope and back wall to increase light. Artificial lighting can be added in places with conditions. Generally, each lamp is 40W, and it is appropriate to install about 25 lamps per 667 square meters. In the weak light season, supplementary lighting for 3-4 hours a day can significantly increase vegetable yield and quality.

The third is to strengthen the scientific management of greenhouse fertilizer and water. In winter, strict fertilizer and water management of solar greenhouse vegetables should be implemented. When the outdoor minimum temperature is below -15℃, watering should be minimized. Choose a sunny day with a minimum temperature of -10℃ or above to water thoroughly, and cover the ground with film to retain moisture. If the vegetables are short of water, choose a good day when the cold wave has just passed and the weather is clear, and use drip irrigation or trench irrigation under the film to irrigate with small amounts of water to avoid lowering the ground temperature. The temperature and air temperature in the solar greenhouse are low in cloudy and snowy weather. The absorption capacity of vegetable roots is weak and the growth and development are slow. Soil topdressing should be minimized, but foliar topdressing can be appropriately performed to alleviate the poor growth and development of vegetables due to low temperature and low light. Generally, 0.3% potassium dihydrogen phosphate plus 0.3% calcium nitrate plus 1% glucose solution can be sprayed on the leaves; or 0.3% compound fertilizer (NPK is 15:15:15) plus 0.2% calcium chloride plus 1% glucose solution.

Fourth, strengthen greenhouse humidity control and disease prevention. In continuous cloudy and snowy low temperature weather, the air humidity in the solar greenhouse is high, which is easy to induce diseases. Ventilation and dehumidification should be carried out for a short time at noon to control the occurrence of diseases. After the disease occurs, use aerosol and dust agents for prevention and control to facilitate uniform application of pesticides and avoid excessive air humidity in the greenhouse. In addition, in the ridges and ditches in the greenhouse, hygroscopic materials such as corn and rice and wheat straw, rice husks, sawdust, etc. should be laid as much as possible to reduce the humidity in the greenhouse.

The fifth is to increase the ground temperature in the greenhouse to promote root growth and seedlings. If the solar greenhouse is still in the stage of land preparation and planting, it is necessary to focus on increasing the ground temperature. Generally, measures such as increasing the application of organic fertilizers and organic materials, wide row cultivation, high ridges and large ridges, mulching, laying organic materials (sawdust, rice husks, broken straw) in the ridges and ditches, drip irrigation under the film, and watering once to reduce the number of watering times can increase the ground temperature by 3 to 4°C and promote root growth and nutrient absorption.

The sixth is to properly control the results. In the case of continuous cloudy, snowy and low temperature weather, the growth and development of vegetable plants are weak. It is necessary to harvest fruits early and thin out flowers and fruits appropriately to avoid increasing the burden on the plants, resulting in weaker plant growth and reduced resistance to stress and disease.