Black-fruited varieties tend to send out more lateral shoots when headed. Heading back should be done early in the growing season to about 2-2.5 feet. The laterals should then be pruned back to 5-6 inches during the dormant pruning. Leaving longer laterals may result in small berries. Fruiting canes of both types should be removed immediately after harvest.
All grapes bear fruit at the base of new shoots coming from year-old canes.
Grapes must be pruned hard for maximum yields. At the first pruning, remove all suckers and canes except the strongest one. Head it back to two buds. The second pruning consists of heading back the main cane on the wires and selecting healthy laterals for each. The number of buds retained will depend on the vigor of the vine.