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University
of Rhode Island GreenShare Factsheets
Grape
Culture
Grapes
are an excellent fruit for fresh use or processing into jam, jelly,
juice, pie or wine. Grapes can also be ornamental and valuable as
shade or screen plants in the home landscape when trained on a trellis
or arbor. Well-grown grapevines of cultivars such as Concord can
produce up to 20 pounds or more of the fruit per vine per year.
Once established, well-tended grapevines can be productive for 40
years or more. Home fruit gardeners can be successful if they select
the right cultivars, maintain a good fertility and pest management
program and properly prune grapevines annually. Grape
cultivars may be of the American, European or French hybrid types.
American and French hybrid types are best suited to northern growing
conditions because they tend to be more winter-hardy. Recommended
American cultivars include Concord, Niagara, Delaware, Reliance
and Canadice. Several French-American hybrids, such as Seyval Blanc
and Vidal Blanc, are recommended for their wine making qualities
and good winter hardiness. Depending
on the cultivars selected, grapevines will produce berries that
may be red, blue, white (greenish-yellow), purple or black with
a distinctive flavor. Both seeded and seedless types are now available.
Some cultivars produce good table grapes while others make better
wine grapes. In
the Northeast, the earliest cultivars begin to ripen about mid-August,
while the latest cultivars produce ripe fruit from late September
to early October. Canadice is an example of an early season cultivar;
Concord is a mid-season cultivar. Reliance is one of the best tasting,
red seedless grapes. Catawba is a popular late-ripening cultivar
used mostly for wines.
By selecting and planting different cultivars in the home planting,
the gardener can spread the harvest over several weeks. However,
if interested in planting only a few vines or even an isolated single
vine, the gardener may do so without worrying about the necessity
of planting different cultivars. Grapevines available to gardeners
are self-pollinated or self-fruitful. Bees are not required for
pollination. Disease
tolerance is another important factor to consider since wet springs,
and hot and humid summers tend to favor common diseases that attack
grapes. Try to select grape cultivars that are least susceptible
to diseases. No grape cultivar, however, is entirely disease resistant.
Early spring is the best time to plant grapevines. Fall planting
is not recommended because plants are likely to be lost to heaving
during the first winter. During the first year, the soil is prepared
for planting, cultivars are selected and vines are planted, mulched,
fertilized and kept free of weeds, insects and diseases. Prune off
broken or dead portions of branches and roots. At the same time,
prune top growth to a single cane. During the first year, tie the
vines to a stake to keep them off the ground, prevent damage and
make spraying more effective. If the first season is dry, supplemental
watering may be necessary to keep the vines growing. It is important
to get as much first-year growth as possible.
Three years are normally required to establish a grape planting.
Vines planted for training on a trellis are normally placed 8 feet
apart, while those planted for training on an arbor can be placed
4 feet apart. Before growth begins the second year, a support for
the vines--either a trellis or an arbor--must be provided. Care
of vines the second year is similar to that of the first year. A
system for training the vines should be selected during the second
year. Vines are trained to a particular system by pruning and tying
the canes to the support system. In some methods of training grapevines,
the canes are tied to wires above the trunk and arms of the vines.
Such training works well where grapevines are to be grown on a fence
or in an upright position. In another method of training, the canes
are tied to the wires and the fruit bearing shoots are allowed to
droop or hang down. A third method is the cordon type training system.
Here the fruiting canes are developed from a horizontal extension
of the trunk called a cordon. If canes are pruned long, they can
be tied to the lower wires. If pruned short, they hang free. One
of the most common training systems is called the single curtain/cordon
bilateral system. Annual
pruning is important in maintaining a uniform yearly production
of quality fruit. The best time to prune grapevines is in the dormant
season after all danger of severe cold weather. Learning to prune
grapevines requires practice and experience.
Grapes perform best where the soil pH is between 5.0 and 6.0. Apply
lime only when soil analysis indicates a need. Apply 8 ounces of
10-10-10 fertilizer per plant seven days after planting. Increase
the amount of fertilizer to 1 pound of 10-10-10 in the second year
and 1 1/2 pounds per vine in the third and later years, approximately
30 days before new growth begins in the spring. Do not concentrate
fertilizer at the base of the trunk; keep fertilizer 6 to 12 inches
from the trunk and spread evenly under the spread of the vine. During
the third season, some harvest may be expected from the vines. The
first full crop, however, will not be produced until about the fourth
or fifth year. It
is important that cultural practices of maintaining soil fertility,
weed control, soil moisture conservation and insect and disease
control be continued not only during the third year, but in subsequent
years as well. Control weeds by hand hoeing or with plastic or organic
mulch. A clean area 11/2 to 2 feet on each side of the vine is necessary.
Do not damage trunks with a hoe or chemicals. Selecting
disease tolerant cultivars, good sanitation practices, managing
vine canopies for good air movement, pest scouting and an effective
spray program are all part of a successful pest management program.
Common grape diseases are black rot, downy mildew, powdery mildew,
phomopsis cane and leaf spot and botrytis
bunch rot or gray rot. Significant insect and mite pests on
grapes are grape berry moth, Japanese
beetle, grape flea beetle, European red
mite, grape root borer and grape phylloxera. Adapted
from Gary Gao, Ohio State University Extension, 2000
Pesticides
are poisonous! Read and follow all safety precautions on labels.
Handle carefully and store in original containers out of reach
of children, pets or livestock. Dispose of empty containers
immediately, in a safe manner and place. Pesticides should never
be stored with foods or in areas where people eat.
When trade names are used for identification, no product endorsement
is implied, nor is discrimination intended against similar materials.
Be sure that the pesticide you intend to use is registered for
the state of use.
The user of this information assumes all risk for personal injury
or property damage.
For more
information, call the URI CE Gardening and Food Safety Hotline
at 1-800-448-1011 or (401)874-2929 from outside Rhode Island;
Monday-Thursday between 9 am and 2 pm.
University
of Rhode Island Cooperative Extension provides equal program
opportunities.
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