How to Prevent Uneven Size Grapes
Here's an introduction on how to prevent uneven size grapes and detailed methods for proper grape care, which are great bits of knowledge. It's recommended to save this for future reference!
Improper water and fertilizer management can cause grapes to have uneven sizes. Insufficient organic fertilizer and microelement supplementation, as well as excessive chemical fertilizer application, can also cause this issue. Daily water and fertilizer management should be strengthened, controlling the amount of water each time and applying a balanced amount of fertilizer, avoiding the excessive application of a single type of fertilizer. Prune the branches and leaves to maintain a neat grape trellis, thinning the fruit appropriately to increase overall light penetration. Let's delve into the details next.
1. Water and Fertilizer Control
Water should not pool after each irrigation, and it should be drained promptly. When watering before flowering, the soil 10 centimeters below the surface should be able to clump when gripped by hand. You can water twice before flowering. If the orchard is in a low-lying area, one watering is sufficient. Strictly control the application of nitrogen fertilizer, as too much nitrogen can cause excessive growth and leafy vegetation. Nitrogen fertilizer can be omitted before flowering, using a small amount of organic fertilizer and supplementing potassium and phosphorus fertilizers during the hard core stage. Spray a high-activity boron-calcium solution on the leaves, as boron-calcium foliar fertilizer can effectively mitigate the uneven size caused by uneven pollination. Foliar fertilizers containing enzyme dynamism enhancers have a higher content of elements and can supplement the required trace elements. Use plant growth regulators in moderation, neither too little nor too much, as this can easily cause uneven sizes.
2. Pruning Branches
Strong branches within 25 centimeters of each fruiting branch should be cut, the terminal buds removed, and only a few buds should be left. Maintaining an overall vigorous tree is sufficient; branches less than 20 centimeters should be pruned entirely. Branches thicker than 1 centimeter can be left with double fruit clusters, while medium-strong branches should be left with one. When the fruit is the size of soybeans, the uneven sizes can be seen. From the base of the branch, cut above the 5-6th leaf.
3. Pinching Tips and Stems
3-5 days before flowering, for fruiting branches with double buds, leave one short and one long when pinching the tips, with the short branch left with 6-8 leaves and the strong branch with 8-10 leaves. Fruit clusters less than 10 centimeters in length do not need to be pinched. For 20-centimeter clusters, pinch off 1/5.
4. Secondary Branch Fruiting
When grape seeds are the size of soybeans, prune at the 5-6th leaf on the branch, cutting off branches that extend outward. This is usually suitable around the end of June.
5. Adjusting Load Capacity
Thin appropriately based on the growth of the fruit clusters. Fruit clusters on branches less than 20 centimeters should not be left, while branches thicker than 1 centimeter and longer than 20 centimeters should be left with double fruit clusters.
6. Rational Use of Hormones
5 days before full bloom, spray the trees with chloroacetic acid and gibberellin to treat the flower clusters, increase fruit set, and make the fruit seedless. 10 days after full bloom, dip the fruit clusters in a 1000 ppm gibberellin solution to lengthen the fruit stems and increase fruit size, reducing the occurrence of uneven sizes. Before the grapes mature, treat with a 500 ppm ABA solution to promote fruit ripening.
7. Supplementing Zinc and Boron
After harvesting, spray the leaves with zinc fertilizer and apply boron fertilizer, or spray 2 to 3 times with zinc fertilizer before and after flowering, and spray boron fertilizer twice during the inflorescence separation stage.
8. Replanting Trees
For varieties like the large Fruiting Grape, which are tetraploid and prone to degeneration, or trees affected by viral diseases and declining vigor, even with watering and fertilization, they may still produce few fruits and have uneven sizes. For such trees, it's necessary to dig them up and replant them to reduce losses.
The above is a complete introduction on how to prevent uneven size grapes and detailed methods for proper grape care. I hope it can be of help to you. Don't forget to check out more flower care tips and knowledge!