How to Train Grapevines
image by Bill Silvermintz
It is important to train a grapevine to attach to a trellis properly in order to prune for the optimum crop. Keeping the vines organized helps the gardener find the particular pieces of vine that need to be tied to the trellis or cut from the trunk. Another reason to train the plants to a trellis is to ensure they receive the proper amount of sunshine. There are a couple of training methods but the most popular is called a four-arm Kniffin. This type of training encourages good production and requires little summer pruning relative to other methods.
After planting the initial vines in the spring, prune to one stem apiece and cut that stem to two or three buds. The initial pruning should start in the early summer, just giving the plants enough time to adjust to their environment. This pruning will help your plant develop a straight trunk and give the roots time to grow and strengthen before all its energy is sent to the vines.
Select the most vigorous 6- to 10-inch shoot from the new growth off the main trunk buds at the end of the first growing season or beginning of fall. Cut the rest off. You can either tie the remaining shoot loosely to a training stake or tie the end of the shoot to a piece of string and tie the other end of the string to the first or second wire of the trellis and allow the shoot to grow up the string to the wire.
Pinch off all lateral shoots from the main shoot. This will help the main vine grow faster and can save you a year of time to establish the main trunk. Grapevines must be pruned every year to produce strong vines for the grapes. Otherwise you will have many weak vines that produce little fruit. When the first shoot reaches the top wire, cut the tip of it off and tie the now-pruned shoot to the wire.
The following spring, remove all but four of the strongest new shoots near each wire. Do the same in the beginning of winter; preserve the four strongest and cut off the rest. From the second group of four, select the strongest two and cut them back, leaving five buds. Tie the weaker two of this group to the wires going in opposite directions. Cut the first group of four to two buds. These are called renewal spurs.
The following winter, remove the two shoots that you tied to the wires in each direction and replace with the strongest two renewal spurs. Cut back new renewal spurs to two buds. Each winter replace the shoots you've tied to the wires and leave new renewal spurs. All other shoots should be removed.