Grapes are the most widely grown fruit in the world and unlike most fruit crops, grapes are native to North America. The wild grapes found by early settlers were quickly rejected because they were high in acid, low in sugar and uniquely flavored.
Grape vines brought from the emigrants' native countries failed to survive the new continent. It took hundreds of years to learn that disease and insect pests unique to North America were not tolerated by European grapes.
Grapes differ greatly in their tolerance to disease and insect pests and to cold winter temperatures. With proper care, grapevines can be grown in most locations in New York, although getting fruit on those vines is often challenging.
Grapes can be eaten fresh, made into juice, dried to make raisins or made into wine. With many varieties to choose from, a gardener can have a long season of delicious grapes with a full range of flavors, colors and uses.
Varieties for New York
There isn't a simple answer to the question of what grapes you can grow at your location. The question that you must first answer is how cold can it get in winter. A single night at subzero temperatures will make grape growing difficult, but not necessarily impossible.
Grapevines grow well at many locations where they will not produce fruit, usually due to cold winter temperatures that the vegetative buds but not the flower buds can survive. If the summers are warm and sunny it is possible to protect vines from winter cold by burying them during the coldest time of the year.
Most grape varieties you find in your supermarket, such as 'Thompson Seedless', will not survive even the mildest winter temperatures in New York (even underground). If you live in an area of the state where grapes are grown commercially, you obviously can grow grapes in your garden.
Grapes are grouped into American, hybrid and European types. The American Concord variety is the most widely planted grape in New York. It can be eaten fresh, made into wine, and it is the basis of the grape juice industry. In addition it is cold hardy and disease resistant.
Recently developed hybrid seedless grape varieties can be made into juice, wine, or raisins in addition to their intended use as table grapes. They are more sensitive to cold winters than Concord.
There is an excellent publication from the grape specialists at the New York State Experiment Station that discusses suitable varieties for our state, your county extension agent can tell you how to get one.
Vines should be spaced 8 feet apart in rows 8 to 10 feet apart. Vines are usually planted in the spring and should be watered during the first growing season.
Each year grape vines grow long shoots which not only produce the fruit of the current growing season but also produce the buds that make the next season's fruit. The brown overwintering shoots are called canes and the number and length of canes left at pruning determines the amount and quality of the next crop.
Grapes are vines, and in the wild they grow to the tops of trees in the forest. They do not do well on the ground and don't stand up well on their own.
Grapes can be trained (actually tied) to many different supports. The simplest, or really the easiest, to construct and maintain is 12.5 gauge high tensile wires (two or three) stretched between posts 16 to 24 feet apart. Hopefully a heavy crop of fruit will make sturdy posts and end anchors mandatory. The top wire is usually 5 feet from the ground.
An arbor is a fancier and horticulturally more pleasing support, but it makes grape growing more difficult. Trellis support should be provided for the grape vines as soon as they are planted, even temporary support if necessary. Also, grape vines growing on the ground are very prone to disease.
Training Young Grape Vines
Young vines must grow for several years before they are strong enough to support fruit. When the vines are planted they should be cut back to 2 or 3 buds. Allow several shoots to grow. The goal is to have an abundance of leaves on the vine to permit the formation of a strong root system.
The second year select two sturdy canes, remove the rest and allow three to four shoots to develop about 4 feet from the ground and make sure they stay attached to the trellis. Remove flower clusters as they form. During the third year you can start regular pruning and allow some fruit to develop.
Grapes require yearly pruning. Unpruned grape vines get very dense, diseases get hard to control and fruit quality declines.
Pruning is not difficult and can be done anytime during the dormant season. Vines are pruned so that they can produce an optimum crop of ripe grapes. The more buds left at pruning, the more fruit will develop. If too many fruits are left through the season, the fruit will be small and even worse, may not ripen.
A good rule is that big vines can have more buds and therefore more fruit than small vines. Keep new growth on the vines near the center of the vine. Harsh winters occasionally damage trunks and new trunks (renewals) should be selected from the suckers growing from the base of the vine frequently, with some varieties this must be done every year and as many as 4 trunks of different ages left during the growing season.
It is simple to leave just enough vine during pruning to allow it to grow to fill the space allotted along the wire, (about 8 feet long). The crop can then be controlled by fruit thinning to no more than one cluster for each rapidly growing shoot.
Fruit thinning is frequently necessary to assure maximum quality and ripening. It is possible (and often necessary) to control excessive cropping by removing fruit during the growing season. The earlier this is done the more effective it will be. To have large berries and large clusters, small or imperfect flower clusters can be removed as soon as they appear.
Grapes have few insect pests, but many diseases. The grape berry moth, native to New York State and always close by where it feeds on our common wild grapes, is our worst insect pest. The adult moth lays eggs in the young fruit which hatch into larvae (fruit worms). It can be controlled without spraying pesticides by the use of pheromones which disrupt mating and decrease egg laying. Alternatively, infected fruit can be picked off the cluster and discarded. One or two insecticide applications can fully prevent damage if desired.
Major diseases are powdery and downy mildews, and black rot. Concord grapes can tolerate these diseases with minimal control but other varieties need more frequent fungicide treatment. Contact your local extension office for information on appropriate pesticides for specific problems. Some varieties of grape can be grown in New York using organic growing techniques. Your local extension office can assist you in selecting organic fertilizers and pesticides.
With many grapes, birds and raccoons need to be controlled as the grapes ripen. Netting is an excellent way of controlling birds. Interestingly, birds do not bother Concord grapes. If netting is required for your grapes, you may be able to use the net earlier in the season on other crops and make its purchase economical.
Raccoons, skunks and opossums love grapes. It is not reasonable to assume that you could grow enough grapes to fill them. A low (6 inches from the ground) electric fence is the best control but again has additional uses. Weeds are difficult to control but any weeds within several feet of the vine must be removed.
Grapes are ready to harvest when they taste good. Some varieties of grapes ripen before Labor Day and others barely before killing frost. Once the leaves are killed by frost the grapes will not develop further and might as well be picked. Your local extension educator can suggest publications on ways to process grapes that you may have in excess. Happy Harvest.
Le Creasy, Professor of Pomology, Department of Fruit and Vegetable Science, Cornell University, Ithaca, NY