Grapes, Kiwi

Today we planted on the grape trellis one each of:

Spur Pruned

• Flame seedless
• Perlette seedless

Cane Pruned

• Himrod seedless (an American hybrid)
• Black monukka

Initial Training

Although vines often are allowed to grow at random, sprawling over the ground during the first season, it’s best to train the stronger of the two canes that develop from the plant to a strong stake, five to six feet tall. Remove any suckers growing from the base of the canes. Remove the weaker cane in March. If neither cane is three feet long, cut the plant back to two buds again the second year.

Apply nitrogen two weeks after planting at a rate of 10 lb of 10-6-4/100 ft of row. Reapply the same rate annually in early spring, right before growth starts. Fertilizer can be applied to a single plant at a rate of 1 lb/plant. Have the soil tested every three to five years. Do not apply fertilizers containing herbicides (such as some lawn fertilizers) in or near the grapes. Four to six inches of mulch may be applied to help control weeds and conserve soil moistures.

Pruning

http://www.extension.umn.edu/distribution/horticulture/DG1103.html

First Year: During the first season, the primary objective for grapevine growth is the development of a large, healthy root system and a straight trunk. When new growth begins, train the two or three shoots that arise from buds on the pruned cane to a training stake. This 4- to 5-foot stake should be set 10 to 12 inches deep and should be long enough to be tied to the first wire of the trellis system. Tie the shoots loosely to the stake several times during the growing season to maintain vertical growth. On each shoot pinch back any laterals to a leaf to encourage rapid extension growth. Keep the vines well-watered and mulched to suppress weeds.

Second Year: In late winter evaluate the amount of growth produced during the first year. If no cane is long enough to reach the cordon wire, remove all but one. Prune this cane back to two buds and treat it as a first- year vine. If a cane is long enough to reach the cordon wire, relatively straight and of adequate pencil-size diameter (about ¼ inch), retain it as a trunk and remove the rest. Cut this trunk-cane through the first node above the cordon wire and tie it securely to the support stake.

When new growth emerges in the spring, select two shoots that are 8 to 12 inches below the cordon wire and on opposite sides of the trunk. Remove all other shoots. When these shoots reach 1½ to 2 feet in length, gently bend them over to the cordon wire and loosely tie them. As these cordon shoots continue to grow, loosely twine them around the wire (do not wrap a shoot more than three times around a wire) and tie them. To avoid damaging the tender shoot, tie the cordon shoot at least 12 to 18 inches from the tip. When the cordon shoots have grown 5 to 5½ feet from the trunk (1 to 1½ feet beyond the halfway point to an adjacent vine), cut them back to 4 feet from the trunk, which encourages lateral shoot growth.

Low-trellis cordon system: Remove lateral shoots that develop on the underside of the cordon and retain the shoots that develop on the upper side.

High-trellis: For American labrusca bunch grapes, remove shoots that develop on the upper side of the cordon and keep the shoots that develop on the underside. For American non-labrusca and American hybrid bunch grapes, prune out shoots that develop on the underside of the cordon and retain shoots that develop on the upper side.

With either system, rub off all flower/fruit clusters as they develop and maintain a good pest control program to protect the leaves.

Third Year: The objective of the third growing season training is to establish vertical arms on each cordon.

Low-trellis: In late winter, head back canes that developed on the upper side of the cordon to spurs of one to three buds. Space the spurs at regular intervals of 4 to 6 inches. Remove all extra shoots and suckers arising from the trunk. When new growth begins, rub off any shoots that develop on the underside of the cordons. Tie the selected vertical shoots to the first catch wire as soon as they reach a length of 18 inches. The sole purpose of the catch wire is to direct the shoots upward. Later in the growing season, head back or hedge the shoots above the top catch wire. Ideally, these shoots should be 4½ to 5 feet long with 15 to 20 leaves.

High-trellis: For American labrusca bunch grapes, retain short canes of four to six buds on the lower sides of the cordons to promote downward growth. Space them at regular intervals of 4 to 6 inches along the cordon. For American non-labrusca and American hybrid bunch grapes, retain spurs of one to three buds or short canes of four to six buds on the upper sides of the cordons. Train the shoots downward to create a “curtain.” Altering the canopy in this manner will improve light interception by the leaves, and most important, will expose the basal four to five buds of the shoots to sunlight. These are the buds that will produce next year’s crop, and the exposure to light will increase their fruitfulness.

During the third season, it is very important to prevent the vines from overproducing. Allow only one cluster of fruit per two shoots to balance fruit production with the accumulation of food reserves in the vine. Continue to maintain a good pest control program.

Fourth Year and Thereafter: The vine must be pruned each year during the dormant season to avoid alternate-bearing and to make harvesting easier. Pruning after growth starts may cause an excessive flow of sap from the cuts. In fact, “bleeding” may occur at pruning in midwinter if fine roots have been stimulated into growth following warm weather. This loss of liquid is not injurious to the vine.

Pruning the mature vine consists of three operations:

The first step is pruning last season’s growth. Evaluate the canes that developed from last year’s spurs. Select straight canes, that developed from basal spur buds (closest to the cordon) and are growing in the right direction for the particular training system. Head back these canes to spurs or short canes as was described in the third year for each system. They should be spaced 4 to 6 inches apart along the cordon.

The second step is to remove water sprouts, suckers, and any tendrils attached to the trunk or cordons.

Finally, prune back cordon growth beyond the 4- foot point or halfway to the next vine. Do not retain any canes on the bends or divide of the cordons.

For both the low- and high-cordon systems, maintain four to six shoots per foot of cordon, removing shoots where necessary. Also, selectively remove leaves from around the fruit clusters to improve fruit quality and help reduce disease pressure. These leaves can be removed shortly after bloom but before the berries begin to change color and soften (the verasion stage). Do not remove the leaves after the berries begin to soften because sunburn may result.

Overcropping will greatly reduce fruit quality and will reduce next year’s harvest by limiting food reserves in the vine. Some cluster thinning in years of heavy fruit set (thinning to one or two clusters per shoot) is the simplest way to ensure that those remaining fruits will develop into larger, more fully ripened clusters. A good rule-of-thumb for mature vines is to allow no more than two clusters per shoot.