There are two general systems for training vines on a trellis. In the “head-trained” system, a trunk is established and a few to several short main branches are developed that sustain renewal spurs and fruiting canes. The canes are placed on a trellis, arbor, or other support system. Cane pruning is typically practiced on head-trained vines in California. See Figures 15.9A and 15.10, linked below.
In the “cordon-trained” system, a trunk and two or more permanent horizontal arms, or cordons, are established and spur pruning is typically practiced. See Figure 15.9B, linked below. The cordons are trained on the trellis and serve as the base for several spurs that produce fruiting canes each year.
Train shooots on the trellis wire in the second year for vigorous vines. Vines or varieties with low vigor may take 1 or 2 additional years to develop. The shoots should be selected from buds that occur several inches (15 to 30 cm) below the trellis wire so the shoots continue in an upward direction as they approach the wires. Allow the main upright shoot to grow approximately 1 foot (30 cm) above the trellis wire, then tie it securely to the trellis. See Figure 15.8C, linked below.
Shoots positioned to grow on the trellis wires should be allowed to grow 12 to 18 inches (30 to 45 cm) long before they are tied down to the wires. See Figure 15.11, linked below. Never tie the growing shoot tips to the wire because they will lose vigor and cease growing. Always leave at least 6 inches (15 cm) of shoot tip free beyond the last tie so it can grow in a vertical direction to maintain vigor.