Grapes produce fruit on lateral shoots on 1-year-old canes. All grapes require heavy pruning to produce fruit, but after the first three growing seasons, different types of grapes need different methods of pruning. Wine grapes and muscadines usually need spur pruning, and American grapes, such as Concord and Thompson Seedless, require cane pruning.
Training spur and cane grapes for the first three seasons
- When you plant: Plant a rooted cutting with two or three buds above the soil line, then bury the roots in light mulch.
- First growing season: Leave the plant alone. It will grow a number of shoots.
- First dormant season: Choose the best shoot and cut others to the base. Prune remaining shoot to three or four strong buds.
- Second growing season: When new shoots reach about 12 inches long, select the most vigorous and pinch off others at the trunk. Tie the remaining shoots to support (arbor post, trellis post). When the shoot reaches the branching point at top of arbor or trellis wire, pinch it to force branching. Let two strong branches grow. Pinch any others at 8–10 inches long.
- Second dormant season: Cut away side shoots, leaving only the trunk and two major branches. Tie these to the arbor top or the trellis wire.
- Third growing season: Let the vine grow. Pinch tips of sprouts on the trunk. After this, spur and cane pruning differ.
Spur training of grapes
Spurs are created by cutting all side branches on the lateral arms to two buds in late winter. Two new shoots grow on the spur you leave, and each produces a cluster of fruit.
- Dormant season: Each spur will have two shoots that produced fruit during the summer. Cut off weak spurs. Cut the stronger spurs to two or three buds. These buds will produce fruit-bearing shoots in summer. Repeat each year. Always keep the trunk clear of growth.
- Summer: When fruit forms from the fruiting shoots, clip the shoot off beyond the next set of leaves past the last fruit.
- Third dormant season: Remove all shoots from the vertical trunk. Choose the strongest side shoots on horizontal branches and cut to two buds. Remove weak shoots at the base, spacing a spur, cut to two buds, every 6 to 10 inches.
Cane training of grapes
Cane pruning involves pruning annually to remove all growth except two whole canes from the previous growing season and two other canes each cut back to a spur with two buds. The whole canes will produce fruiting shoots for next season and the spurs will form replacement canes for the following season. On a two-wire trellis, follow this procedure for both wires.
- Annually: When the outside cane has borne fruit, cut it back to the inside stub, now holding two or three new canes. Select the best and tie it to the trellis for fruit. Cut the next cane to two or three buds. Remove the weakest at the base. Repeat each year.
- Third dormant season: Remove shoots from the trunk. Cut horizontal branches back so that two long shoots remain on each. On a two-wire trellis, you can leave up to eight shoots per vine. Tie the shoot farthest from the trunk to the trellis. Cut the other to two to three buds. The tied shoot will fruit the following summer. The clipped shoot will produce growth to replace it the next winter, and fruit the year after.