Did you girdle the fruit-bearing canes?
Did you reduce the number of produced clusters of grapes on your vines?
Did you reduce the number of fruits on each cluster of grapes?
Girdling removes a narrow ring of bark from around the base of the fruit-bearing cane. What this does is prevent the nutrients that are already in the branch from returning to the stem and roots of the vine through tubes called phloem, which is located just beneath the bark. Removing the bark interrupts the phloem. The extra nutrients go toward making grapes bigger and plumper. To girdle a cane, scrape off a 1/8- to a 1/4-inch-wide ring of bark near the base of the fruiting cane early in the season, just after the flower parts have fallen off the young grape cluster.
Table grapes often make more clusters of grapes than the branch can properly nourish. If all the clusters try to develop, fruits are small and often poor in color and sweetness. Just after the flowers have finished blooming and the flower parts are falling off, look over your grapevine and remove any forming clusters that are poorly shaped, too big, or too little. Then look at each branch and estimate how many bunches each shoot should successfully nourish.
Thinning of the number of grapes growing on each cluster makes individual grapes larger. You'll notice that some table grapes have so many fruits in a cluster that they get pressed together and are limited in their growth. Give grapes a chance to grow larger and to get more plant nutrients and water per grape by shortening the cluster. Take off the bottom half of the cluster, leaving four to five side branches near the top. Since these branches grow sideways from the cluster's main stem, they have room to hold fruit without crowding.
Grape size is affected if annual pruning isn't carried out to limit the number of fruiting canes that develop each year. If grapevines grow unchecked, grape production and quality decline. The annual pruning, which should remove about 90 percent of the previous season's growth, is essential for producing large-sized grapes.
https://homeguides.sfgate.com/increase-size-diameter-table-grapes-105205.html
Sreten null
Hi! I’m Sreten Filipović. I graduated from the Faculty of Agriculture at the University of Belgrade, with a master's degree in Environmental Protection in Agricultural Systems. I’ve worked as a researcher at Finland's Natural Resources Institute (LUKE) on a project aimed at adapting south-western Finland to drought episodes. I founded a consulting agency in the field of environment and agriculture to help farmers who want to implement the principles of sustainability on their farms. I’m also a founding member of the nonprofit organization Ecogenesis from Belgrade whose main goal is non-formal education on the environment and ecology. In my spare time, I like to write blog posts about sustainability, the environment, animal farming, horticulture, and plant protection. I’ve also published several science-fiction short stories.
You can find me on LinkedIn at https://www.linkedin.com/in/sreten-filipovi%C4%87-515aa5158/
