Start Thinking About Grapes - December 20, 2000
Jeff Schalau, County Director, Agent, Agriculture & Natural Resources
Arizona Cooperative Extension, Yavapai County
Three weeks ago, I encouraged pecan growers (one tree qualifies) to enter their pecans in the upcoming Camp Verde Pecan and Wine Festival on February 10, 2001. Although there will be no wine contest at the Festival, four Arizona wineries will be selling their products and providing samples. I know of three Verde Valley grape wine producers in early stages of production (one large and two small), but I am curious how many others are making wine (grape or otherwise). Let me know and maybe we can organize a wine contest for the 2002 Festival. Whether you want to make wine or simply grow fruit for consumption, grapes are easy to grow and can be a rewarding backyard crop.
The Verde Valley is and excellent location for grape vines. The soils and climate are well suited and even if we can get a late spring frost that kills the fruit blossoms, grapes vines are often capable of producing a fruit crop on secondary growth.
Finding the best site for grapes is similar to that for deciduous fruit trees. They prefer: full sun; deep, fertile, well-drained soils; and a slight slope (preferably south facing) to drain cold air on chilly nights. Grape vines should be planted 6 to 8 feet apart and will need support of some kind. Backyard gardeners often use old-fashioned wooden arbors or more economical wires stretched between metal fence posts. Commercial growers use more sophisticated trellis systems.
Bareroot vines should be planted and are available through nurseries and catalogs. Roots should only be pruned if they are damaged. It is important to keep roots moist at all times before and during planting. Planting holes should be wider and deeper than the root system. Spread the roots evenly over a low cone of soil sighting the plant so that it will be at the same soil height as it was when growing at the nursery. Cover the roots with native soil (not amended soil) and bring the finished grade up to the aforementioned planting height. After planting, mulch the vines with compost, well-rotted manure, straw, hay, or leaves to conserve soil moisture.
First year care is critical to grape vine establishment. Irrigate newly planted grapes often enough to keep soil moist but not waterlogged. Do not fertilize grape vines during the first year. The roots are tender and easily burned. Weed control is also important because competition for resources will slow growth.
Newly planted vines should be pruned back leaving only the most vigorous cane. This single cane should be pruned back to leave only two buds. During the first growing season, stake the plant and leave the stake until the trunk can stand without support. Select the most vigorous one and prune off the other closely. Once the cane reaches 60 inches, cut back to 40-50 inches to promote branching below the cut. During the first dormant season, select four lateral canes near the top and prune off all others. The four remaining canes should be pruned back to two buds. These will develop into fruiting canes. You may also need to protect the vine from rabbits, deer, and javelina.
Mature grape vines should be pruned yearly during the dormant period for maximum yields and maintenance of good growth form. To prune, select two vigorous canes near the top of the plant and two farther down. Next to each of these, choose another cane and cut it back to two buds (these are renewal spurs). After selecting four canes and renewal spurs, cut off all others closely. Finally, prune the remaining four canes back to 8-15 buds. These will produce fruit the following year. During the next dormant season, remove the fruiting canes from the previous year and follow the same procedure.
After the first year, irrigate deeply (3-4 ft.) every 2 to 4 weeks. Soil should be allowed to dry out between each irrigation. Nitrogen fertilizers should be applied to bearing vines. About one-half pound of ammonium sulfate (21% nitrogen) should be applied to each vine. If you choose to grow your grapes organically, then you must know the percent nitrogen of the organic fertilizer you plan to use. Steer manure is usually about 0.5% nitrogen or approximately one-fortieth the amount found in ammonium sulfate. Apply about 20 pounds of steer manure to get the same amount of nitrogen (40 times as much by weight).
Many varieties are well suited to the Verde Valley. You can contact the Cooperative Extension office for more information on these. Birds are very fond of grapes, so either have them netted or plan on sharing. The grape leaf skeletonizer is a common insect pest of grapes. The larval stage (worm) feeds on the underside of the leaves. This pest can be controlled by various methods.
Finally, I hope to meet all of the local grape enthusiasts at the Camp Verde Pecan and Wine Festival on February 10, 2001. For more information about the Festival, call the camp Verde Chamber of Commerce at (928) 567-9294. See you there!
The University of Arizona Cooperative Extension has publications and information on grapes and brambles. If you have other gardening questions, call the Master Gardener line in the Cottonwood office at 646-9113 or E-mail us at firstname.lastname@example.org and be sure to include your address and phone number. The Yavapai County Cooperative Extension web site is http://ag.arizona.edu/yavapai/.
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Last Updated: March 15, 2001
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