Perhaps the single most important factor in producing abundant grape crops is the proper training and pruning of the vines.
Pruning at Planting
At planting time, you should choose one vigorous cane that will become the trunk of your grape vine. The cane you have chosen as your trunk should be pruned to 2-3 buds. All other canes should be pruned back completely. If using a trellis system, place a stake in the ground as close to the new planting as possible. As the remaining cane grows, tie the cane to the stake so that it grows upward toward the cross wire(s) on your trellis.
Pruning after the First Season
Pruning of dormant grape vines should be done in the early spring. Thus, pruning after the first season should be done in March (i.e. just before the beginning of the second season). Here are some guidelines for pruning after the first season:
• Remove any lateral canes
• If the main cane has reached or extended beyond the desired wire, tie it to the desired wire OR prune it back to just below the wire to promote new cane growth.
• If the main cane did not reach the desired wire, prune back to wood that is at least 3/8” thick.
Pruning and Training During the Second Season
Once the trunk reaches the height of the desired wire, begin training any proximal canes to the wire. Other considerations during the second season:
• Remove any canes growing lower on the trunk.
• Remove any shoots (suckers) emerging from the ground.
• Remove grape clusters when they begin to bloom.
Pruning after the Second Season
Now is the time to choose the cordons (lateral portions of the trunk) on a trellis system. Choose the healthiest, most vigorous canes to form the cordon. Prune these canes back to 2-4 buds each. Prune all other laterally growing canes back to a single bud.
Pruning and Training During the Third Season
During the third season, you may allow some crop formation. You do not want to let the vine carry a full crop, so thinning should be done to promote further vine establishment. As during the second season, remove any canes that develop lower down on the trunk, as well as any suckers that may emerge.
Pruning after the Third Season and Subsequent Dormant Seasons
Once your vines become mature, you prune based upon the weight of the previous year’s growth. This is called “Balanced Pruning.” The steps for Balanced Pruning of American cultivars are as follows:
• Estimate the weight of all the one-year-old fruiting canes.
• Remove all one year-old canes except those closest to the trunk or cordon and that appear vigorous enough for good fruiting.
• Weigh the canes that you have removed.
• Follow the “30 + 10” rule: Retain 30 buds for the first pound of canes removed and another 10 buds for each pound thereafter. For example, if the total weight of removed canes is 2 lbs., you would retain 40 buds (30 for the first pound and 10 for the second).
• Remove any extra buds to achieve the calculated number of buds.
• The maximum number of buds retained for the next growing season should not exceed 50.
For French-American hybrids, you should follow a “20 + 10” rule. As with the American cultivars, the maximum number of buds retained for French-American hybrids should not exceed 50.
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