Why Does the Same Bunch of Grapes Have Uneven Coloring?

1. Too Much Nitrogen Fertilizer and Too Little Potassium Fertilizer

• Grape is a grape variety that needs more potassium.

• The ratio of nitrogen, phosphorus, and potassium demand of grapes should be 1:0.7~0.9.

2. Over Irrigation

Due to the excessive water and fertilizer, the vegetative growth of new shoots is too strong, and the green is too late, which is not conducive to the coloration of grapes.

3. Poor Light Transmission

As the pinching and thinning were not completed in time, the branches and leaves were too prosperous, resulting in serious shading, poor ventilation, and light transmission, so the anthocyanins were not easy to form and could not be colored.

4. Adventitious Shoots Heading Late

If the vineyard is subject to frost, the main buds in the winter buds may freeze to death, while the secondary buds may have weak growth potential and late heading due to insufficient nutrition, so the grape spikes grow slowly and it is difficult for the grapes to be colored and mature early.

5. The Measures to Promote Grape Coloring Did Not Keep Up

• Bagging time is too late

• The large dark leaves on the ear are not removed

6. Excessive Humidity

Timely moisture removal is conducive to the smooth progress of leaf photosynthesis and the improvement of leaf photosynthetic products.

8. Hyperthermia Disorder

If the temperature is too high (over 30 ℃), anthocyanins are not easy to form, leading to non-staining.

9. Pest Damage

In the process of cultivation, the leaves are damaged by diseases and insects, resulting in low photosynthetic efficiency, slow sugar content increase, and inability to color