Pruning grapes depends on how your decide to grow them in your garden and how much space you have. Fences are ideal to use as support for vines. Vines can also be contained to one stake in the ground. If you have an arbor or pergola, grapevines can be grown over the top to produce shade. Remember, flowers and fruit are located on buds that developed the previous year. Therefore you need to encourage new growth, but not too much.
For the first year, pruning is the same no matter how you plan to train your vine; the key is to develop a strong root system and straight trunk. Depending on the size of the vine that you buy, prune the vine back to one straight cane. Tie this cane to a stake or to the fence and encourage it to grow straight. You might have to tie it multiple times during the first year to keep it straight. When the vine gets to the top of the fence-this might be the year you planted, or it might be in the spring of the following year-remove an inch or two of terminal growth to force the vine to branch. Train two branches, one in each direction, by tying them to the fence in opposite directions to form permanent branches running along the top of your fence. Remove any buds that start to grow lower on the trunk. This will make managing the vine much easier.
Once the trunk has reached as high as you want, and the lateral trunks have been formed, prune the vine each spring before growth begins so the developing canes have enough air movement around them to reduce diseases. There are many different methods and techniques for training vines; we recommend you experiment with pruning vines to make them an integral part of your landscape. Remember, fruit is produced on the current season's growth, that in turn grows from last season's wood. Heavy pruning provides the best fruit. Light pruning results in large yields of poor-quality fruit; very heavy pruning produces too much vegetative growth and very little or no fruit. Table, juice, and jelly varieties can have 40 to 60 buds per vine after pruning, but wine varieties should have only 20 to 30 buds per vine after pruning.