What is the cause of watermelon cracking in greenhouse when the weather is hot?

First, the reason of watermelon fruit cracking:

(1) drastic changes in soil moisture lead to fruit cracking: (1) high temperature and drought lead to a large number of fruit cracking in some watermelons during expansion. During the fruit expansion period, fruit cracking is mostly caused by sudden flooding or continuous rainstorm after continuous drought, and a large amount of nutrients are input into the fruit, which makes the pulp grow much faster than the peel and forms cracked fruit. (2) This year, when watermelon was planted, it was cold and rainy, and some Gua Tian didn't irrigate slow seedling water, so it was short of water at the fruit-setting stage, which led to fruit cracking.

(2) Generally, thin-skinned watermelons are easy to crack, such as Huang Xiaoyu, Hong Xiaoyu and 84-24. And the skin thickness is only about 0.5 cm. When the fruit is about to mature, if it cracks slightly, in case of continuous rain and sudden flooding due to continuous drought, it will cause a lot of cracking.

Second, the preventive measures:

Appropriate furrow irrigation can determine the degree of water shortage according to the wilting and recovery of leaves, and combine with the local meteorological forecast to ensure that furrow irrigation is carried out under the premise of no rainstorm in the recent 3-4 days, and the water content should be uniform. It is best to use drip irrigation.

When melon fruit cracking is serious, in order to prevent fruit cracking caused by sudden rainstorm after continuous drought, a large amount of nutrients can be properly controlled to flow into the fruit. The specific method is to select two small bamboo sticks with the width of 1/3 and the diameter of the stem and vine, and insert them vertically into the melon and vine; Insert the pin vertically into the fruit handle instead of the bamboo stick; The purpose of reducing fruit cracking can be achieved by gently twisting vines or fruit handles with your hands.