Three Possible Problems that may be encountered with Growing Grapes in Polytunnels

1. Warming up too early, the amount of cold required is not enough

(Insufficient grape cold demand, resulting in soft grape ripening cold demand refers to the number of hours of effective low temperature required to break the natural dormancy of deciduous fruit trees). Some farmers blindly advance the temperature to get to market early, believing that the earlier the temperature is raised, the earlier the ripening, resulting in a lack of grapes needing cold. The normal dormancy period for grapes is 30 to 45 days. There are some differences between each variety. If the temperature is raised too early or improperly, it will cause the new tips to stop growing and fall off.

The date of warming up is determined by the insulation capacity of the facility, the length of the dormancy period, the number of days of fruit development, and the fruit ripening period. The important thing is to make sure that the warming is done at the right time. Premature warming is detrimental to the growth of grapes.

2. High temperature and humidity cause grape excessive growth and serious diseases

When grapes are planted in polytunnels, the temperature and humidity are increased in the early and late stages of growth. The high temperature and humidity will promote the growth of branches and leaves. Excessive growth of branches and leaves is not conducive to material accumulation, resulting in low fruiting rates and difficulty in increasing yields.

3. Blindly pursuing high yield and neglecting quality

In grape production, there is the problem of one-sided pursuit of high yield and neglect of improving quality, blindly increasing production in pursuit of profit, uncontrolled load, overweight whole branches, too small leaf-to-fruit ratio, insufficient nutrient supply from fruit maturity to sugar accumulation, poor color and sweetness, and even leading to soft grains during grape maturity.