Grape vines come in a vast number of varieties, and if you have one that is overgrown, you face a challenge to get it back into a healthy state. A healthy grape vine consists of a single trunk and four strong branches. After you get your overgrown vine properly pruned, you will be able to train it and maintain it on an annual basis. In addition to maintaining a manageable-sized vine, you should prune to position the fruit growth close to the main stem and to allow sunlight in. Prune after the vine has lost its leaves in the fall and before the buds appear in the spring.
Pick a main trunk and prune away any stems that are the same size as your main trunk. Cut these large stems at ground level.
Locate a cane on each side of the main trunk, and mark these two canes by tying a ribbon or string around them. These canes will be the source of the upcoming year's growth.
Shorten the two marked canes, leaving approximately 10 buds each. Make your cut in front of the 10th bud.
Cut back two additional canes on each side, leaving two buds on each cane. Make your cut in front of the bud. These are called spurs. The spurs will become the fruit-bearing canes in the next growing season.
Remove all remaining growth. You should only have a trunk, the two marked canes and the two spurs.
Tie the two marked canes to your support wires or trellis. You can use plastic ties. The structure of your newly pruned grape vine should resemble the letter T.