Growing grapes in the home garden

By Melanie Mathieson
The Gardening Guru

Grapes can grow in Rainy River District if varieties adapted to our cold, dry winters and short growing season are chosen.
When making the decision to plant grape vines, it is very important to be aware of our hardiness zone (Zone 4) and to check the tag on each variety as each one has to be treated individually.
Grapes need full sunlight and high temperatures to ripen, so plant on southern slopes, the south side of windbreaks, or the south sides of buildings. Avoid northern slopes and low ground since these will be cooler throughout the growing season, which delays ripening of the fruit.
Choose deep, well-drained soils to avoid standing water in the spring and encourage early growth.
Plant your vines in the spring as soon as the soil can be worked. Use healthy plants with well-developed root systems and space the plants six -eight feet apart.
Before planting the vine, remove all canes except the most vigorous one. Trim off any broken or excessively long roots.
Dig a hole large enough so you can spread the root system out without bending the roots. Plant vines at the same depth as they have been placed in the pot (do not plant too deeply).
Spread the roots and cover them completely with soil. After planting, shorten the remaining cane to two strong buds (each bud will develop into a cane).
Grapes need a good water supply when they are actively growing in the spring and summer. They should be watered at least once a week in areas of little rain (and more often under droughty conditions).
Regular watering should be continued until the berries begin to turn colour. After colouring, watering is not needed and will, in fact, slow the ripening process.
Once the leaves have fallen in the fall, one last large watering should be undertaken before the ground freezes to get the vines through the winter.
Growth habit determines the trellis type and how the grapevine will be trained and pruned (read the tag for guidance).
All grapevines can be trained to climb a trellis or support system. I have grapes growing on one side of my dog pen, with the goal being to create shade for the dog and have fruit at the end of the season.
There are many reference sources available for directions on constructing grapevine supports. You also can use the grapevine in your landscape purely for decoration or for hiding unsightly areas.
The ripening season for grapes is August through October. When to harvest your grape crop will depend on the variety you chose to plant. Unlike other fruits, grapes don’t ripen once picked, so you want to make certain they are ripe before harvesting.
You’ll know your grapes are ready when:
•they no longer increase in size and aren’t as firm to the touch; and
•they have turned their mature colour and the seeds have turned from green to brown.
Grapes generally ripen three weeks after they begin to change colour.
Of course, tasting your harvest is one of the best ways of determining ripeness. The clusters ripen on top first.
When a taste test tells you that a grape chosen from the top is ripe, wait a day or two and then taste one from the bottom of the cluster to see if it’s sweet. If so, start harvesting.
Make certain to use sharp shears so as not to injure the plant. Lift the cluster and cut the stem, leaving enough length to be able to handle the cluster later.
Perhaps the biggest mistake home gardeners make when growing grapes is neglecting pruning the vines each year. Pruning removes 90-95 percent of the previous year’s growth.
It keeps the vines in balance and aids in controlling the crop and ripening the fruit. Pruning the grapevine is an art, not a science.
When pruning, keep in mind that fruit is produced on the current season’s growth that, in turn, grows from last season’s wood. Heavy pruning provides the best fruit.
Light pruning results in large yields of poor-quality fruit while very heavy pruning produces too much vegetative growth and very little or no fruit.
You can refer to a reference book or website for more detailed instructions on pruning.
If you are thinking of growing grapevines in your backyard or garden, be sure to consider the above factors before you start planting.
Choose your grape varieties based upon what you plan to use them for, how they are adapted to the local growing conditions, and plan the trellis according to the variety’s growth habit.