To begin the process of training a vine, select one shoot growing from the wood that you planted the previous spring and remove all other growth. Cut the selected shoot just below the third bud.
During the second spring, the vine will produce many shoots. Once these shoots grow to about a foot in length, select the most vigorous upright shoot and break off all other growth by hand. This shoot will become the trunk of the vine. To prevent the breakage of the shoot and to ensure that the trunk will be straight, tie this shoot to the stake as it grows. This should be done about every 10 days until the shoot approaches the height of the wire.
There are many ways to train a vine. Up to this point, all training techniques will be the same. I will present one common method that will work well for all varieties grown in a backyard.
Once the shoot grows near the wire, it should be cut about 12 inches below the wire. At this time, remove all lateral shoots on the lower two feet of the vine and save at least five lateral shoots at the top of the vine. As these shoots develop, loosely wrap them around the wire.
In the winter, select two or three of the shoots (canes) for fruitwood and cut them so there are 10 to 12 buds per cane. The other two or three canes should be cut just below the third bud. These short canes will produce shoots that will be fruitwood for the following season. By the fourth year, you can begin pruning, as you would prune a mature vine.
>> Pruning a mature vine
The first step is to select four to eight canes that will produce fruit next season. The number of canes left will depend upon the vigor of the vine. If the vine is vigorous, leave more canes; leave fewer canes for weak vines.
Look for thick canes that are close to the trunk. If possible, select canes that are growing from year-old wood left last winter rather than canes produced directly from the trunk. Cut these canes so that there are 10 to 15 buds per cane.
Next, select healthy canes at the base of each of the fruiting canes you just selected. Cut each of these healthy canes so that there are two or three buds per cane. These short canes are called "spurs." There should be two to four more spurs than fruiting canes. These spurs will produce little fruit during the coming season but will produce shoots that will become the fruiting canes summer after next. Therefore, consider what leaving these canes in certain positions will do to the shape of the vine next season.
The last step that involves cutting is to remove all of the growth that you did not select. Then wrap the long canes around the wire. If necessary you can tie the end of the canes to the wire. If you don't have a trellis, you can pull all the canes upward and tie them together.
The goal of pruning is to train a vine that is balanced, that has canes that can easily reach the wire and that has renewal spurs that will help to ensure that the vine continues to have these characteristics the next season.
Grape vines can be a high-maintenance component of a home landscape, but with good training and pruning you can increase the likelihood that the vine will be long lived, that there will be excellent yield and that the vine will be attractive.