Four key points of winter management in greenhouses!

    Greenhouse wintering management is an important production management link linking the previous and the next, laying a solid production foundation and improving output. Overwintering management direction and technical ideas should be the main line of anti-freezing and preservation of seedlings, and heat preservation to promote growth, and the key to promote tree erection, control main diseases and insect pests, rational fertilizer and water management, and implement symptomatic management.

    1. Temperature management

    Plant's own cold tolerance and matching of warming and thermal insulation facilities

In the growth of overwintering greenhouse crops, among the four elements of water, fertilizer, air and heat, temperature is the most active factor for crop growth. Antifreeze to protect seedlings and heat preservation to promote growth are the top priorities of greenhouse overwintering management. Mainly from the aspects of enhancing the cold tolerance of the plant itself and the matching of warming and thermal insulation facilities.

    One is to provide suitable greenhouse facilities according to the temperature requirements and growth characteristics of different vegetable crops.

    ● For crops with high temperature requirements for tomato and melon, implement double-shed four-film mulching cultivation.

   ● At the same time, in order to enhance the light transmission and heat preservation performance of the film, it is better to use a new film for the outer top film, which is conducive to the early market of vegetable crops and the improvement of commodity value.

    The second is to implement the ventilation and dehumidification method of "later ventilation and early cover" for heat preservation and temperature increase in winter greenhouses. During the wintering greenhouse stage, the light is weak and the temperature is low. During this period, temperature is the most active factor for hair tree growth. Temperature and humidity management should focus on increasing and prolonging the effective growth temperature.

    ● Adopt the method of closed shed and gap ventilation before January. The closed shed should not be too long, generally no more than 5 days, to prevent the harmful gas concentration in the greenhouse from being too high and the carbon dioxide concentration being too low, which will affect the normal growth.

   ● Generally, the temperature should not exceed 30 degrees during the closed shed. The gap ventilation should be controlled in fine weather. In the case of low winter temperature, in principle, the shed should be opened in the downwind for ventilation. When the weather is fine and no wind, the upper wind can also be slightly ventilated to speed up the moisture removal and increase the gas exchange in the shed.

    ● If it is cloudy and sunny for a long time, the ventilation time should not be too late, and pay attention to ventilation only on one side to prevent the leaves from losing water due to transpiration.

    The third is to control air leakage and run heat. Some details can not be careless. For example, the joint of the film should be tight, the inner and outer skirt film and the bottom film should be in contact with the ground, and the soil should be solid. Repair even small holes.

    Fourth, focus on improving the cold tolerance of plants. Different crops have different cold tolerance, and the same crop has different cold tolerance. It is mainly related to the concentration in plant cells. Nitrogen fertilization, vigorous growth, soft long-shade plants, etc., the concentration of cells in the body decreases, and the cold tolerance decreases.

Therefore, more attention should be paid to rational fertilization, reasonable ventilation and dehumidification, and coordination of the relationship between vegetative growth and reproductive growth for overwintering vegetables.

    Under normal climatic conditions, with the above measures in place, there will not be many problems in greenhouse vegetables overwintering. In order to prevent extreme cooling weather, a wind barrier can be built at the north air outlet, covered with grass felt, and other emergency thermal insulation and heating facilities can be added to ensure that the seedlings are not damaged.

     2. Disease prevention and pest control

     Focus on key points, be safe and effective

    The occurrence of pests and diseases is conditional and regular, and it is necessary to prevent and control overwintering vegetable diseases. It is necessary to coordinate the relationship between thermal insulation and ventilation and dehumidification, make full use of agricultural control measures, and flexibly use chemical spray control and fumigation control methods. Implement timely prevention and control, adhere to symptomatic prevention and control, and choose the right time and appropriate spraying equipment for prevention and control.