How to prevent spring frost (late frost)?

Spring frost (late frost) refers to the phenomenon when the temperature drops below 0℃ after warming up in spring. When the daily average temperature drops to the lowest limit for the growth and development of pear trees (ie, the critical temperature), some organs of the pear tree will be damaged by freezing.

The main organs of pear trees damaged by spring frost are buds, flowers, and young fruits. Some foreign scholars believe that the dangerous temperature for freezing damage is -2.2℃ in the bud stage and -1.7℃ in the flowering stage. Some people also believe that flower pots will suffer varying degrees of frostbite at temperatures between -3 and -1°C. But whether you will be harmed depends on the duration of the low temperature. Generally, the duration of low temperature is less than 4 hours, and although there is frost damage on the surface of plant organs, it can usually recover.

The main measures to prevent spring frost:

First, choose varieties that are suitable for cultivation in the region and can withstand late frost.

The second is to delay the flowering period so that the flowering period occurs after the late frost. Such as pear orchard irrigation or sprinkler irrigation, spraying B9 before flowers, painting tree trunks white, etc.

The third is the fumigation method. According to the weather forecast, at night before frost occurs, a number of smoke piles are set up in the orchard. When the canopy temperature drops to 1°C, the smoke is ignited to cover the pear orchard, reduce ground heat dissipation, and warm the air in the garden.

Fourth, the remedial measures after frost are: strengthening soil, fertilizer and water management to promote growth; spraying boron, urea and gibberellin on flowers to increase fruit setting rate.