What causes soft berries in grapes?
When grapes reach the final stage of ripening and harvest, softening followed by dropping of the berries often occurs, and there are many different reasons for this phenomenon. But the end result is always the same: it seriously affects the quality and yield of the grapes and causes them to lose their commercial value. So what exactly causes soft berries in grapes? Let's take a look together!
1. Improper fertilization
The amount of fertilizer needed throughout the grape growing period is relatively large, but the growth stages of grapes place certain demands on how much fertilizer is used. For example, if compound fertilizer is applied excessively during the stage from berry enlargement to veraison, fertilizer burn is likely to occur, killing the roots and preventing them from supplying nutrients, which results in nutrient deficiency. And if nitrogen fertilizer is applied one-sidedly in order to increase yield, the grapes will absorb too little calcium fertilizer, causing excessive vegetative growth of the leaves, which take up too many nutrients, leaving the fruit short of calcium and causing soft berries.
2. Climatic factors
According to the results of experimental investigations, soft berries in grapes generally occur at the highest rate during rainy weather. And if such weather occurs while the grapes are coloring, the grapes will undergo reduced photosynthesis due to insufficient light. Without enough sugar in the grape plant, soft berries develop. After rainy weather, the rain causes serious loss of fertilizer, and without enough nutrients and water, softening also occurs.
3. Planting too densely
The planting density of grapes should not be too sparse or too dense. Too sparse leads to excess nutrients in the grapes, excessive vegetative growth of the branches, and fruit cracking. But too dense causes the branches and leaves to be overly crowded, shading each other, so the lower leaves get no light and cannot carry out photosynthesis, and ventilation and air permeability become poor. The branches, leaves and fruit also need a large amount of nutrients, and the decline in photosynthetic capacity leads to insufficient nutrition, with branches, leaves and fruit competing for nutrients, causing nutrient imbalance within the fruit and resulting in softening.
4. Too much fruit set
Many growers, in pursuit of high yields, pay no attention to the flowers and fruit of the grapes and do not thin the fruit or prune the flowers. As the fruit grows larger, the branches carry more fruit than they can bear, and there are no nutrient branches. As many flowers as there are on a branch, that many fruits are kept, which lowers the leaf-to-fruit ratio and far exceeds what the grapevine can bear. This leaves the leaves unable to supply the fruit with sufficient nutrients, and the sugar content of the fruit drops sharply, ultimately making the grapes sour and soft.
There are many other causes of grape softening, such as pests and diseases, waterlogging, hormones and many other factors. Grapes are very sensitive and fragile during their growth process. The orchard must be managed diligently, water and fertilizer must be applied appropriately, and treatments must be chosen according to the condition of the grapes. Use various pesticides reasonably. To learn more about grapes, please keep following Qinnong Web!