California is famous for its wine grapes, but did you know it is easy to grow your own table grapes at home?
Not only will you get sweet, luscious grapes, but the vines can be trained over a patio or pergola, providing a nice shady spot in summer!
How to grow grapes
Pruning grape vines
The variety of grapes being grown determines which of two pruning methods to use.
Grapes are either spur-pruned or cane-pruned. This is because different grape varieties produce fruit on different bud spurs.
‘Thompson Seedless’ and ‘Concord’ are cane-pruned grapes. Cane-pruned grapes should be pruned so that 2-4 horizontal arms (‘bilateral cordons’) can be trained along each of the horizontal trellis wires. One cane-pruning method is called the Four Arm Kniffen method and the University of Maine offers an excellent how-to video here.
Spur-pruned grapes are more productive so it is necessary to limit their crop to only two canes per wire. ‘Flame Seedless’, ‘Tokay’, and ‘Ribier’ are spur-pruned grapes.
In either case, you will want to trim each cane to have no more than 14 spurs. Otherwise, all the plant’s energy will go into vegetative growth, rather than producing grapes.
While most of a grape vine’s roots are in the top 3’ of soil, some of those roots can go down as much as 15’ deep! Grapes perform best when they are watered deeply and allowed to dry out between waterings. The amount of water needed depends on the type of soil, the depth of the roots, and the weather. At the peak of summer, grape wines may need 8-10 gallons of water per day, if a drip system is being used. On average, a deep watering every 2-3 weeks, during summer, is adequate. During cooler or wet weather, little or no water is needed. Once your vines have bloomed, it is important to water regularly, rather than allowing the soil to dry out. As fruit develops, erratic watering can lead to water-stress and cracked fruit.
Feeding grape vines
If grapes are being grown in rich soil, nothing needs to be added. Too many nutrients can reduce or eliminate fruit production. Remember, in the plant world, it’s all about reproduction. Grapes are the reproductive part of the vine. If the plant doesn’t feel the need to reproduce, it won’t.
Assuming your soil isn’t perfectly rich, nitrogen and potassium can be added before berry set. (‘Berry set’ is when the grapes are 1/4” in diameter.) Zinc should only be added before the vines bloom. The only way to know if these additives are needed is to have your soil tested by a reputable lab.
To reduce the chance of pest problems, harvest grapes as soon as they taste ripe. Unripe grapes will not ripen off the vine. Grape clusters should be cut, not pulled, from the vine, and then cooled after being harvested. Do not rinse grapes off before storing them. Do that just before eating.
Pests & diseases of grapes
Spider mites, aphids, mealybugs, cutworms, thrips, click beetles, leafhoppers, branch and twig borers, and ants can infest grape vines. Diseases such as Eutypa Dieback and Pierce’s Disease can infect grape vines and powdery mildew is a common problem. Birds and rodents can also wreck havoc on your harvest. Monitor grape vines regularly for these pests and diseases to ensure timely control. Contact your local County Extension office for information specific to your region.
While grape vines take some time to become productive, an established grape vine can produce fruit for 50-100 years! Only one or two vines are needed to provide a family with an abundance of grapes.
Get yours started today!
You can grow a surprising amount of food in your own yard. Ask me how!