For centuries a symbol of “the good life,” grapes fit even postage-stamp size (but sunny) gardens because they grow up, not out. After careful planting, grapes reward you luxuriously with plump fruit in two or three years. When calculating how and where to raise grapes, keep in mind that at least 150 days of frost-free weather are needed.
Although most grapes are self-fertile (Scuppernong is an exception), you’ll get best results by planting two different varieties in your yard or garden. Choosing the right variety for your part of the country is important. For Denver area, Campbel Early, Concord, Niagara, Niabell, Blue Lake Catawba, Delaware. Some seedless varieties include Himrod, Interlaken, Concord Seedless, and Romulus.
Choose a site that offers protection from strong winds and unexpected late frosts. A northern slope is perfect because temperatures are generally more even there. If possible, run vines in an east-west line to cut down on shade cast on vines by the trellis. This also will help dry up rain or dew quickly, cutting down on diseases.
Grapes need a nutrient-rich and well-drained soil. Before planting, would in moderate amounts of rotted manure or compost. Do not overfertilize. Rampant vines are soft and tender and will succumb easily to severe weather.
In the spring, as soon as the soil will accept a spade, plant one- or two-year-old vines obtained from a reliable nursery or garden supply center. Set vines in the soil so that the soil line matches original planting depth at the nursery. Then cut back all vines and branches to a single stem with at least three remaining bugs. If plants are planted in rows, allows seven to eight feet between vines.
Care & Feeding
Grapevines will twist and twine around everything within reach unless snipped and trained to grow where you want them. If you want shade for a patio or screening for privacy, limit pruning to the removal of scraggly growth and old canes. For quantities of luscious clusters, serious pruning is in order each year. The most popular training method is called the four-arm Kniffin system. The idea is to prune vines in such a way that four canes are allowed to develop and bear fruit, while four spurs are carefully preserved for the following year.
First, construct a trellis consisting of two stout posts sunk into the ground. Then stretch two wires so the bottom wire is about 30-36 inches from the ground. The second wire should be 24-30 inches above the first. After the first season and during the midwinter or very early spring when the plant is dormant, tie the central cane to the top wire. If there is a confusion of canes, select the most vigorous for the central stem. Cut the cane off slightly above the wire and snip off all other growth. If the cane doesn’t quite reach the top wire, fasten a piece of bamboo or lath as a bridge between the wires and tie the cane to the wood.
After the second or third season, new growth will be vigorous enough to select four of the best canes for the “arms.” Cut back to about ten buds per cane and tie to upper and lower wires. Also, leave stubs with two buds each to become next year’s renewal canes. Then remove all other canes and stubs. Every winter the previously bearing canes are removed to make room for the renewal growth.
Well-rotted manure is the best fertilizer for grapes. If none is available, use a good garden fertilizer – a pound and a half for each mature vine.
Insects & Diseases
Thwart the host of diseases and bugs with prevention. Plant vines in a sunny, fairly open spot where good air circulation is assured. To protect against fungal diseases, use a reliable fungicide at rates recommended on the label. If insects threaten to defoliate the vine, spray thoroughly with an insecticide labeled for use against them. Some growers shroud the ripening clusters in paper bags as a defense against wasps and bees.
Don’t be fooled by a purple grape. Most varieties change color well before they have arrived at peak ripeness and flavor. Let taste me your guide. A fully ripe grape, ready for picking, will be sweet and bursting with juice. To harvest, cut the entire cluster from the vine.