Bunch Grape Culture As A Hobby Alabama Cooperative Extension Service, Auburn University, Alabama 36849-5612

CIRCULAR ANR-12

Table Of Contents Page

Best Place To Plant . . ............ . .... . ... ... . . . . . .. . 3

Varieties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Purchasing Plants .......... . ..... ... . . . . . .. . .. . . . .. . . 5

Planting The Vine ............... . .... . . . .. . . . . . . . . . . 5

Trellis Systems And Trellis Construction . . . . .. ... .. . .. . . .. . 6

Training Young Vines ............. . . .. . . ... . . .. . . .... . 7

Pruning The Mature Vine .......... . ... .. .. ... . .. ... . . . 9

Fertilization ..................... . . ..... .. . . .. . . . ... 10

Cultivation And Weed Control ...... .. .. ..... . . . ..... . . 11

Insects And Diseases ............. .. . ... . . ... . ..... .. 11

Bunch Grape Culture As A Hobby

American bunch grapes (Vitis labrusca) have been grown in home plantings in Alabama since the state was first settled. Culturing bunch grapes at home can be both fun and rewarding, but producing good grapes requires timely work. A good site, proper variety selection, carrying out a season-long spray program, pruning and fertilization are keys to success. Bunch grapes require close care and attention. Therefore, only the dedicated gardener should attempt to grow them.

Grape yields are influenced by many factors . The most impor­tant are variety and season. However, for planning purposes, estimate your vineyard size based on a 20- to 30-pound per vine average for mature vines. In most years and with most varieties, 30 pounds per vine is a realistic estimate under good growing conditions.

Best Place To Plant The site should be in full

sun most or all of the day. In North and Central Alabama, a late spring frost can reduce yields significantly, so bunch grapes should be planted on elevated sites. In fact, in all areas of the state, low spots where cold air settles should be avoided.

Well-drained loam or clay loam soils are best. Bunch grapes also grow well on heavier clay soils; however, ex­cessive vine growth and de­layed maturity may result. Avoid extremely sandy soils and areas where water stands after heavy rains.

1. North Alabama 2. Central Alabama 3. South Alabama

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Varieties Many varieties of bunch grapes will perform well in North Ala­

bama. Some French hybrid grapes (wine grapes) are also suggested for trial there. Several new hybrid bunch grapes are worthy of trial in Central and South Alabama.

VARIETIES RECOMMENDED FOR NoRTH ALABAMA.

Fredonia-A deep purple grape, early midseason, vigorous, pro­ductive, with medium to small clusters of large berries. Berries ripen uniformly. Prune moderately.

Niagara-A white grape, midseason, vigorous, productive, me­dium size, with compact clusters of large berries. Prune heavily.

VARIETIES SuGGESTED FOR TRIAL IN NoRTH ALABAMA.

Catawba-A reddish grape, late midseason, vigorous, moder­ately productive, with large clusters of large berries. Grown commer­cially for wine.

Delaware-A reddish grape, late midseason, medium to low vigor, moderately productive, with small clusters of small berries. High quality, use for eating fresh or for wine.

Interlaken Seedless-A white, early, moderately vigorous grape with medium clusters of small, nearly seedless berries. A good table grape.

Chancellor (Seibel 7053) -A dark red grape, late midseason, productive. A French hybrid wine grape.

Seyval (S.V. 5-276)-A white, early midseason, moderately pro­ductive grape. A French hybrid wine grape.

Villard Blanc (S.V. 12-375) -A white, late, vigorous grape, highly productive. A French hybrid wine grape.

Venus-A seedless, blue-black grape, medium vigor, moderate­ly productive.

Chelois (S 10878) -A blue-black grape, early ripening with me­dium compact clusters, very productive. A French hybrid wine grape.

VARIETIES SuGGESTED FOR TRIAL IN CENTRAL AND SouTH ALABAMA.

Several hybrid bunch grape varieties have recently been developed which are worthy of trial plantings in the southern half of Alabama. All of these have good resistance to Pierce's disease, the primary lim­iting factor to bunch grape culture in the southern portion of the state.

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The following varieties are suggested for home plantings.

Lake Emerald-A green to golden grape, used largely for wine, pancake syrup, other forms of processing, and as a rootstock. Fruits generally ripen in early August. Does well on own roots.

Stover-A golden grape, vigorous, suitable for table use or pro­cessing. Holding qualities not as good as Thompson Seedless* but better than Lake Emerald. Should be grafted on Tampa, Dog Ridge, or La·ke Emerald rootstock for best performance.

Blue Lake-A blue grape, especially good for juice and jelly. Plants are vigorous; 'fruit ripens mid-July. Does well on own roots.

Roucaneuf-A pink grape introduced as a wine variety. Should be grafted on Tampa, Dog Ridge, or Lake Emerald rootstock. A French hybrid wine grape.

MissBlue-A vigorous, dark blue grape with compact clusters. Appears resistant to Pierce's disease.

MidSouth-Similar to MissBiue, although clusters are more open. Good for eating fresh or making jelly.

There are a number of other bunch and hybrid grapes that may do well in certain small areas of the state. If you wish to try them, plant only a few in case they don't do well. European grapes (Vitis vinifera) have not done well in the deep South and are not recom­mended.

Purchasing Plants Bunch and French hybrid grapes, unlike muscadines, do notre­

quire cross-pollination. Therefore, it is not necessary to buy two or more varieties. You may, however, want several varieties to extend the fruiting season.

Most bunch grapes are sold as 1- or 2-year-old plants. Generally, the 2-year-old plants grow off better and are ~orth the small, extra investment. Be sure to buy them from a reliable source.

Planting The Vine Since most bunch grapes are somewhat less vigorous than the

native muscadine, only 10 feet of row will be required for each vine. Lay off the rows at least 10 feet apart (12 feet on hilly land). Straight rows are better for level or slightly rolling land; contour rows are rec~ ommended for hilly terrain. Prior to setting the vines, soil test and •Thompson Seedless is not recommended for Alabama because of susceptibility to Pierce's disease.

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adjust the soil pH to 6.0 to 6.5 with dolomitic limestone. Dolomite supplies magnesium, and most Alabama soils are low in that element.

To plant, prepare a hole large enough to accommodate the en­tire root system in its natural spread. Set the plant at or slightly lower than the level it grew in the nursery. Fill the hole with topsoil and firm it. Do not put fertilizer in the hole. (See Fertilization, page 10.) Water liberally.

After pfunting, cut the vine back to a single stem with two or three good buds remaining. When growth begins, you will select the main trunk of the vine from the stronger of these shoots.

Trellis Systems And Trellis Construction Two trellis systems are commonly used to train bunch and hybrid

grapes in the South: the double curtain and the four-arm kniffin.

The double curtain trellis system is probably the most desirable of the two systems because more grape foliage is exposed to direct sunlight, increasing yields. This system provides two wires 4 feet apart and 5 feet above the ground. Figures 1 and 2 show details of how to construct the double curtain trellis.

The four-arm kniffin training system is considerably less expen­sive to construct. However, the foliage on the lower fruiting canes are shaded by the upper canes, which reduces the quality and pro­ductivity of the grapes on the lower wire. Figure 3 shows construc­tion of the two-wire vertical trellis used for the four-arm kniffin.

Figure 1. Details for constructing the double curtain trellis.

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Training Young Vines Immediately after planting, cut back the strongest cane to two or

three strong buds. Remove any other canes. It is sometimes difficult to determine the condition of a dormant vine. When that is the case, leave five or six buds and, when growth starts, allow only the most vigorous or desirable ones to develop into shoots.

If you cannot construct your trellis the first growing season, drive a stake 4 to 5 feet high in the soil near each vine and train the new growth to it. Tie the shoots loosely or use plastic tape to avoid the possibility of girdling.

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Following the first growing season, the plants should be trained to the trellis system you will use.

FoR THE DouBLE CuRTAIN-Develop a double trunk for each vine approximately 30 inches above the ground (Figure 4). This is done by pinching off the growing point and forcing two shoots to develop. Train one trunk to grow to one of the trellis wires and the other trunk to the other wire. Under ideal conditions, the double trunk system should be developed after the first growing season.

FoR THE FouR-ARM KNIFFEN- Develop a single strong shoot from the young plant by removing competing shoots. Train this shoot to a string or stake running from the upper wire of the trellis to the ground.

The second year should be devoted to developing a strong plant that can support some fruiting during the third season. Figure 4 shows vines properly trained to the double curtain trellis; Figure 5 shows pruning and training to the two-wire trellis.

With normal growth during the first growing season, all buds re­maining on the trunk after pruning are capable of developing into shoots and producing fruit. However, fruit production at this stage of vine development will reduce vegetative growth and, therefore, is not desirable. Remove flower clusters when they occur. And, remove all shoots below the bottom trellis wire, including suckers -from the base of the vine. Some of the French hybrid varieties are especially prolific at this young stage.

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Figure 4. The double curtain trellis system showing ~ double trunks, fruiting canes, and renewal spurs.

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1\ Figure 5. The four-arm kniffin system showing: (1) pruning after first year's growth; (2) after two growing seasons; (3) after three growing seasons.

Pruning The Mature Vine Grapes require heavy annual pruning during the dormant season

to maintain quality and productivity. Because of Alabama's mild cli­mate, pruning should be done during January and February. Late winter or spring pruning will cause "bleeding," a flow of sap through the pruning wounds. But, don't be alarmed if this should happen be­cause it does not damage the plant.

Since bunch and hybrid grapes are somewhat more susceptible to diseases than muscadines, the vines have to be pruned different­ly. Muscadines are trained to have a trunk, fruiting arms, and spur clusters. On bunch and hybrid grapes, healthy canes from the previous season's growth are used each year in place of permanent arms. This is done to avoid a large buildup of overwintering disease organisms in the old bark of the fruiting arms.

Balanced pruning is a method of pruning to balance production and vine vigor. To balance prune, select four canes of last summer's growth, one to run in each direction on the two wires. Select these from canes arising from the four renewal spurs. Canes about the dia­meter of a pencil are most desirable. Cut each of these back to leave 15 to 20 buds per cane. Next, gather up all of the pruned canes and weigh them. (Note: Do not weigh older wood-only last season's canes.) As a rule, 30 buds should be left on the vine for the first pound of prunings and 10 buds for each additional pound. For example, if a vine pruned to 70 buds yielded 31f2 pounds of prunings, the num­ber of buds should be cut to about 55-30 for the first pound and 25 for the other 21f2 pounds. Each of the four canes left, then, should be pruned back to have about 15 buds each.

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If you do not balance prune, then most mature vines should be pruned to have between 30 to 60 buds. The more vigorous the vine, the more buds should be left.

Leave renewal spurs to form canes for next year. Select these spurs from canes of last season's growth and prune them back to leave only two buds each. From these spurs will grow the fruiting canes for next year. Renewal spurs should be located as near the trunk as possible. Figure 6 shows how the vines should look after pruning.

Renewal spurs-two buds

Fruiting canes (Previous season's growth)

Figure 6. Properly pruned vine showing fruiting canes and renewal spurs. Each plant on the double curtain or two-wire vertical trellis should be pruned like this.

Fertilization Establishing the proper fertility level before planting helps get young

vines off to a good start. Contact your Extension county agent for assistance in taking a soil test before planting.

After the plants have been settled by a drenching rain and before growth starts, apply 1/4 cup of 10-10-10 fertilizer around each plant. Keep the fertilizer at least 6 inches from the vine. Repeat at monthly intervals until mid-July.

On 2-year-old vines, double the first year's rate and use the same monthly intervals. Bearing vines will need from 1 to 4 pounds of 10-10-10 per plant applied in March. If growth is poor on producing vines, apply 1 pound of 10-10-10 per plant in May.

Because Alabama soils are inherently low in magnesium, foliar magnesium deficiency frequently becomes noticeable in mid-summer. You will recognize this deficiency by a yellowing between the leaf veins on the older grape leaves (Figure 7). If the soil pH is low enough to need lime, use dolomitic lime to help prevent magnesium deficien­cy. Otherwise, magnesium sulfate (epsom salts) should be applied and watered in. For young plants, apply 2 ounces around each vine, keeping the salts 6 or more inches away from the trunk. Apply 4 to 8 ounces per mature, bearing vine. It may require 2 to 3 years of magnesium application to bring the level up for best plant performance.

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Figure 7. Leaf showing characteristics of foliar magnesium deficiency.

Cultivation And Weed Control Make every effort to establish a permanent sod between rows be­

fore planting the vineyards. This will reduce soil erosion. After the sod is established and the vines are planted, hand weeding and hoe­ing will be necessary around the individual vines during the first two growing seasons. Keep the sod mowed during the summer months.

Once the vineyard is established and producing fruit (generally, the third season), use herbicides to keep the strip along the rows free of weeds and grasses. Several weed control chemicals cleared for use on grapes do an excellent job if properly used. They can be applied with tractor-mounted or hand-operated equipment. See your Exten­sion county agent for specific weed control recommendations.

Insects And Diseases Since bunch grapes are susceptible to a number of diseases and

are attacked by several insect pests, a season-long spray program will be necessary to produce good fruit. "Spraying Home Orchards," Cir­cular ANR-50, gives details on how to protect grapes from insects and diseases. You can get a copy at your county Extension office.

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Arlie A. Powell, Horticulturist-Fruits and

T.B. Hagler, formerly Head, Extension Horticulture Alabama Cooperative Extension Service

Auburn University with

R.M. Crassweller & M.E. Ferree, Extension Horticulturists The University of Georgia

Issued in furtherance of Cooperative Extension work in agriculture and home economics, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture. The Alabama Cooperative Extension Service, Auburn University, Ann E. Thompson, Director, offers educational programs and materials to all people without regard to race, color, national origin, sex, age, or handicap and is an equal opportunity employer. UPS, 2.5M19, 8:88, ANR-12