The best time to prune your vines is i n late winter. The end of January to early March is the best time for pruning, the grape vines are inactive. Their dormancy during this period allows you to cut away the old, neglected vines that don’t produce anything. Getting rid of these vines will help to produce more grapes in the future.
In the late winter period, you should be eliminating 90% of the wood on the vines. Most of the vines produced in the previous season needs to be pruned. Most gardeners don’t prune enough of the old growth. Leaving this wood will limit the amount of grapes you’ll harvest in the spring/summer season. Light pruning not only affects the number of grapes you harvest, but it also lowers the quality of the grapes. When enough of the old wood is removed, better quality grapes come in.
For the best winter pruning, cane pruning is a recommended method. Start by selecting two to four new fruiting canes per vine. Cut back each of these canes, leaving 15 buds per cane (20 to 30 buds per plant for wine grapes). This should amount to 50 to 80 buds per plant. You should leave a two-bud spur cane near the fruiting cane with one or two buds each. These will help to create the canes for the next season. All other cane growth should be removed.