Grapes can be bagged after thinning and shaping. At this time, the temperature is not high, the humidity is low, and the infectivity of bacteria is poor, which is beneficial to the ears and will not bring bacteria into the bag. The best time for bagging in a day is after afternoon 16. During this time, the temperature in the bag is low, so the grapes can adapt to the temperature in the bag and are not easy to get sunburned. The ears in different positions should have different bagging methods. Bagging grapes with strong light on the periphery of vines, with white paper facing outwards to prevent sunburn, and then turning the transparent side upside down when it is necessary to color. At this time, the grapes have adapted to the growing environment in the bag and can be colored quickly. Grapes with weak backlight ears under trees and in the middle of trees should face the sun, so that grapes can get enough light and achieve better coloring effect. You can also adjust the bagging direction according to the market time to control the ripening time of grapes, and realize batch coloring and batch picking.

For reference.