Grapes like heat and most of the sweetest grapes tend to like plenty of sun and warm temperatures. Most of the continental US is in the grape belt between 30 - 50° N. latitude. Cool season plants produce less sugar and are higher in acid. Most areas can grow grapes but check with your County Extension service for tips on the healthiest, most productive varieties for your region, then research detailed cultivation types specific to that variety for the most reliable performance.
Depending on your purpose (i.e., eating, drying, or making juice or wine), climate, and cultivation, a single plant can produce as much as 25-30 pounds of fruit. To get the most from your plants, plant vines where they will get a good southern exposure. The optimum placement is in full sun oriented on a North-South axis. This provides the optimum amount of light and heat.
Grapes like deep, well-drained loam soils. Soils that are either too clay-ey or too sandy tend to retain too much water or drain too quickly, so amending the soil to maintain even moisture is important. They also like somewhat acid soils with a pH of between 5 and 5.5. Mulch with fir or pine needles to eliminate weed problems and maintain the pH.
Plant spacing should be about 5–8 feet apart in rows with 8–12 feet between rows. In home gardens, if you plant a sod walkway between rows and fertilize or compost the grass, you will probably not need to add extra fertilizer for the grapes which have far reaching root systems that are capable of harvesting nutrients from some distance.
Young grape plants like humid conditions and can be put outside if the temperatures are above freezing. Keep them out of direct sunlight until they are acclimated ... usually a week or two.
Pruning grapes is important to ensure large bunches of good sized grapes. Though the plants will grow without pruning, you'll notice fewer, smaller bunches over several seasons.
Because grapes are a vine, it's important to give them some structure. You can train them over an arbor, trellis, or along wires. The wire trellis systems used by vintners have sturdy 4x4 wood posts with tightly stretched 9–12 gauge wire running from post to post. Wire vise clamps can be used to secure the wires.
Though there are different pruning systems for grapes, we use the 4-cane Kniffen method. It's fairly straight forward, so it's easy to maintain your grapes if the varieties are hardy and need no winter protection.
Because grapes produce fruit on year-old canes, you'll want to select four young canes to keep (two per side). The canes should be shiny, with a smooth tight brown bark. Canes that are two years old show cracking and peeling and will be removed. Select canes that are the diameter of a pencil or a bit more if possible, one on each side of the plant at a distance of about 36 and 60 inches from the ground. Use bright yarn or tags to mark the canes you want to keep.
Pruning should be done early in the spring or late winter. Depending on where you live and your growing season, it could be from January to March. It's best to prune before the sap starts to run, however. Pruning a little too late means that you could leave exposed cuts that will drip profusely and that could attract pests.
Planting clean, disease-resistant varieties is often useful, especially if you want to avoid using chemical controls.
Birds are often a nuisance with many berries and fruits. Grapes are no exception. Netting to prevent birds from getting to the grapes or flash tape that flutters in the breeze are both effective ways to deter them.
Products Available at TSC for Growing Grapes:
- Wood posts
By Cindy Shapton