Grape vines are popular among home gardeners for the abundance of fruit in a small space. The vines must be trimmed back every year for a good yield and healthy fruit. Learning how to prune grape vines also means learning how the grapes are produced. It is the second year's growth that generates the fruit. By the third growing season, the grape vines will be in full production.
Mark the first, second and third year growth using the marking tape or colored cloth strips. By marking the different vines, you will have a better knowledge of which vines to prune and which ones to train onto the trellis.
Remove any fruit and excess leaves for a clear view of the growing vines. At this point, cut off any unwanted new shoots or growth coming from the main trunk. Tie any new vines to the trellis or growing system so they are trained for next year's growth. These vines are called cordons and will become a permanent part of the grape vine as it grows. The vines produced by the cordons will be the ones pruned in the future.
Cut back the third year growth, or the ends of the existing cordons, leaving four or five nodes in place. These spurs will produce replacement vines for next year's fruit production. They should be trained to hang down from the existing vines. Check the ties of the vines to ensure they will not detach from the trellis over winter. Replace any worn or broken ties.
Prune the second year grape vines, using the shears or hand saw, but be careful not to damage the other vines around the area. There should be an average of 30 to 40 buds left on the grape vines when you are done pruning. The second year growth is generally the vines hanging down from the cordons.
Untangle any shoots still intertwined with the other vines. Position these green, or new, shoots so they will be growing downward during the next growing season. You can prune these vines also, if they are thicker than a standard pencil. Smaller vines will suffer winter shock and possibly die if they are pruned.