Early spring vegetable seedlings pay attention to antifreeze
When greenhouses cultivate vegetable seedlings in early spring, they are prone to frost damage if they encounter cold weather. In order to prevent seedlings from freezing, measures should be actively taken to prevent freezing.
One, increase lighting
With strong sunlight, the photosynthesis of the seedlings is strong, and there are also many nutrients such as sugar and starch produced, and the cold resistance is strong. In order to make the seedlings more light, in the temperature range where normal growth can be maintained, cover should be covered as early as possible to cover the late cover, cloudy, rain and snow should be opened cover; it is best to use high light transmittance No drip or dustproof film, while the plastic film should always keep the film surface clean.
Second, control the humidity of the greenhouse
The humidity in the shed is large, the water content of the seedlings in the larvae is high, and the concentration of the cell fluid is low, so that the seedlings are easily chilled. In early spring, because the temperature is low and the light is weak, if the humidity in the greenhouse is too high, it is not only susceptible to freezing damage, but it is also prone to infection. Therefore, the number of times of watering and watering should be strictly controlled in the early stage to prevent the soil and air humidity in the shed from being too high. When the humidity in the booth is too high, it is necessary to enhance ventilation and humidity. Ventilation must be performed at a high temperature around noon to prevent cold air from blowing directly onto the seedlings and causing freezing damage.
Third, scientific fertilization
Do not apply nitrogen fertilizer, so as not to weaken the cold resistance of the seedlings. Increase potassium fertilizer can significantly increase the cold resistance of seedlings. In addition, the use of sweet and sour liquid sprayed on the leaf surface, can increase the degree of sugar and hardness of mesophyll, and improve cold resistance.
Fourth, strengthen coverage
In the early spring season, the exterior of the solar greenhouse shall cover the outer insulation materials such as cotton quilts and grasshoppers at night, and keep the outer insulation coverings always in a dry state. The interior of the greenhouse shall be covered with multiple layers such as hanging curtains and buckled arches. Plastic sheds should also be covered with multiple layers. Grass curtains are enclosed around the outside. The bottom of the shed is surrounded by a plastic film to prevent cold. The shed is hung with two curtains, a small shed, a cover film, and a non-woven fabric directly covering the seedlings. Superior. It can also be used as a windbreak in the north of the greenhouse to protect the wind and cold.
Fifth, take temporary warming measures
When the daytime temperature in the shed is lower than 15°C and the nighttime temperature is lower than 5°C, cold injury or freezing injury may occur. In case of cold weather, it is necessary to take necessary temporary warming measures at night to artificially supplement heat. Temporary heating equipment such as heaters and stoves can be installed in the sheds, but chimneys must be sent to the outside of the sheds. It is not possible to warm them with open flames to prevent poisonous gases from damaging the seedlings when fuel is burned.
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