How to Prune Grapes With the Kniffin System

Select the healthiest cane at planting and cut it back to two buds. Remove all other canes.

Select the most vigorous cane in the dormant period preceding the second year and remove all others. If the cane is tall enough to reach the top wire, cut it off at the height of the top wire and tie it securely to the wire. If the cane is not tall enough, tie it to the first wire. Plants having no canes tall enough to reach the first wire should be trimmed like newly planted vines.

In the dormant period preceding the third year, select two vigorous canes close to the level of each wire and remove all the others. Cut those canes back to two to four buds. These will grow into the arms. Allow the central cane to grow to the top wire on those plants that were not tall enough the previous year.

Select a fruiting cane and a renewal spur at the site of each arm in the fourth and subsequent years. The renewal spur should be a first-year cane close to the trunk, and the fruiting cane should be the next healthy cane away from the trunk. Shorten the renewal spurs to two buds and the fruiting canes to four to six buds on less vigorous plants, 10 to 12 buds on more vigorous plants. Remove all other growth, including suckers from the trunk or base of the plant.