How to prevent vegetable frost in spring

Spring cold can be divided into two types: low temperature freezing injury and late spring frost. The chilling injury mainly occurred in February-April, which caused root rot, seedling death, flower and fruit dropping and early bolting of spring vegetables. Late spring frost usually occurs in the middle and late April, which causes frost on the surface of growing vegetable plants in the field and damages them. Preventive measures are as follows:

The first is to temper seedlings at low temperature. After the seedlings come out, the seedbed should be ventilated. With the warming of the weather, the ventilation rate should be gradually increased, and the seedlings should be exercised at low temperature to improve their cold resistance and adapt to the outdoor low temperature environment.

Second, increase facilities. There are two ways to increase protection facilities:

(1) Erect the wind wall. Wind barriers can block cold air and prevent the surface from further cooling.

(2) Ditching for planting and covering with plastic film. When planting vegetables in early spring, furrow planting can be used, and the depth of furrow should exceed the height of vegetable seedlings, and then plastic film should be covered on the furrow.

Third, temporary heating. When the cold current comes, we can build a simple coal stove or install electric lights in the seedling shed or production shed for temporary heating to improve the temperature in the shed and prevent freezing injury.

Fourth, irrigate well water. When strong cold air passes by, the weather is clear, there is no wind or breeze at night, and the temperature drops rapidly, especially when the local surface temperature drops below 0℃. When frost occurs, well water can be poured on the ground to greatly increase the surface temperature.

Fifth, light the smoke. Smoking in the field can effectively reduce or avoid frost disasters on frost nights. But pay attention to two points:

(1) Fireworks should be densely packed, so that the smoke screen basically covers the whole park.

(2) The ignition time should be appropriate, and it should be ignited in the windward direction from midnight to 2-3 am until sunrise, and the smoke screen should be hung on the ground for the best effect.

Sixth, the right amount of water. Before frost occurs, spraying water on the plant surface with a sprayer can slow down the temperature drop, increase the content of water vapor in the atmosphere, and reduce the frost damage.

Seven, timely cultivation. Tillage before frost can alleviate frost. As the temperature rises gradually in spring, the loose soil can better absorb and store solar heat energy. Once the frost comes, it can be relieved because some heat is accumulated in the soil.