I planted several grapevines last year. How should they be pruned this spring?
By the second year, the home gardener should have selected the training system and constructed the appropriate trellis. In early spring, select a vigorous, straight cane and remove all the rest. Tie the cane securely to the uppermost wire with string. Cut the cane off just above the wire. As the buds begin to swell, select and retain 4 to 6 buds in the vicinity of each wire and rub off (remove) all the remaining buds. Later, remove all flower clusters that may form on the shoots. Fruit production at this stage of development will reduce vegetative growth.
If the best cane does not reach the lowest wire on the trellis, it should be pruned back to a point where it is approximately pencil-size in thickness. Weak plants may require a second year to develop a strong trunk.