Grape rowing • In Virgin· EXTENSION DIVISION POLYTECHNIC INSTITUTE AND STATE UN1Vt.R1fY PUBLICATION 5 REVISED NOVEMBJR 1979 CONTENTS

Page Introduction and History 1 Location of ------2 Site and soil------2 Variety selection ______2 American hybrids ______2 French-American hybrids ______3 Vinifera 3 Muscadine ------3 Virginia introductions ______4 Propagation ______4 Cuttings ______4 Layering 5 Grafting 6 Establishing the vineyard ------6 Site preparation ______--_ 6 Planting ------6 Trellis construction ______6 Training systems ------7 Four-arm Kniffin ______7 Umbrella Kniffin ______7 Single Curtain Cordon------8 Geneva Double Curtain ------8 Training young vines ------8 Pruning mature vines------9 Fruiting habits of ------9 Time of pruning------9 Severity of pruning------9 Tying the vines ------10 Cluster thinning------10 Soil management ------11 Cultivation ______11 Fertilization ______11 Pest control------11 Harvesting ______12 Time of harvesting------12 Yields------12 Method of harvesting ------12 Handling and storage ------12 Vineyard Establishment Costs ------13

The research on which this publication is based was conducted by G. D. Oberle, Professor Emeritus of Horticulture, and R. C. Moore, Associate Professor Emeritus of Horticulture. Appreciation is given them for their original work on earlier ver- sions of this publication. The Alwood shown on the front cover was developed, selected, and named by R. C. Moore, Associate Professor Emeritus of Horticulture, and a member of the V. P. I. Horticulture Department for 42 years. Alwood was released in 1967. GRAPE GROWING IN VIRGINIA Revised by E. L. Phillips, C.R. O'Dell, and C. L. McCombs * Departrne11t of Horticulture

Grape growing has received serious attention locally as French hybrids, or, more correctly, as in Virginia since soon after the arrival of the French-American hybrids. Developed primarily first English colonists at Jamestown in 1607. for use in making, some of these hybrids Although native grapes were abundant, they are also good as table grapes. They are becom- failed to win the approval of the colonists due ing increasingly popular in America and some to the strong flavor and odor. In 1619 cuttings varieties have performed quite satisfactorily in of the best wine grape varieties grown in France Virginia. were brought to Virginia. The vines soon "sick- Although commercial production of the Euro- ened and died". pean, or vinifera, grape in North America is con- This was repeated many times in Virginia and fined primarily to irrigated areas in California other eastern states with the same results. The and adjoining states because of its requirement European varieties lacked winter hardiness, were for a less humid climate and less severe winter susceptible to fungus diseases endemic to this temperatures, sufficient information has accumu- area, and were totally lacking in resistance to lated in recent years to indicate that selected va- the grape root louse ( vastatrix). Only rieties can be grown under some eastern condi- in California and a few other areas having a tions. Test plantings have been under way for similar mild and dry climate was a successful a number of years in several of the eastern grape wine and table grape industry based on the growing states, and more recently at various loca- European grape, vinifera, established in tions in Virginia. Successful production is ex- the United States. pensive and time-consuming, however, as it in- Chance cross pollination of the imported Euro- volves special cultural care, careful selection of pean varieties with American bunch grape spe- rootstocks, adjustments in pruning systems, fruit cies, particularly , resulted in - thinning, and additional sprays to protect fruit lings which combined many of the desirable char- and foliage against insects and fungus diseases. acteristics of both parental types and fewer of The muscadine grape, Vitis rotundifolia, is na- the undesirable characteristics. From these tive to the southeastern states and adapted only chance seedlings came such varieties as Alexan- to areas having relatively mild winters and long der, Catawba, Concord, Delaware, , Nor- growing seasons. Some progress is being made ton, and many others. This opened the door to toward developing new varieties that will mature the profitable commercial grape culture in the their fruit in areas having-shorter growing sea- eastern United States. Intentional hybridization sons and whose vines will withstand winters of of European and American varieties and careful lower temperatures. For the muscadine varie- selection of the resulting seedlings has led to the ties now available, suitable growing conditions improved varieties of American bunch grapes in Virginia are found only in the southeastern now available. counties. Richmond and Petersburg probably are The grape root louse, carried abroac about 150 as far west as they can be expected to grow well, years ago on roots or cuttings of American spe- with Richmond and the York River being the cies of grapes, spread rapidly across most of the northern limit. grape growing regions of Europe. The existence of the industry was seriously threatened until it Demand for grapes in Virginia far exceeds the was found that the vinifera grape could be supply in most local markets, and additional vine- grafted easily on roots of the American species yards could prove profitable, if well managed. and thrived on them. In a very few years the Commercial grape growing is a specialized busi- European grape industry was converted almost ness, however, and requires thorough knowledge entirely to vines grafted on American roots. and skill. Prospective growers should first de- Hybridizers in France soon recognized that termine whether or not their soils and locations grafting the grapes involved additional expense are suitable for the type of grapes they desire in establishing and presented hazards to grow. Then, only the best available varieties in maintaining the vines. They, too, crossed Eu- should be chosen for planting. ropean varieties with wild grapes from America Once the vineyard is planted, a carefully planned and selected seedlings which escaped or resisted program of the best practices of pruning, fer- attacks by the phylloxera. These hybrids, often tilizing, weed control, and pest control should referred to as "direct producers" because they be followed in order to produce large crops of could be grown on their own roots, are known high quality grapes. Sufficient capital is needed to finance the cost of , posts, wire, fertil- • Extension Fruit Specialist, Extension Specialist, Small Fruits and izer, spray materials, equipment, and labor for Vegetable Production, and Head, Department of Horticulture, respec. tively. the first 4 years, until the vines reach full bear-

(1) ing age. Vineyards may be expected to bear conditions. Although they can be grown on a profitably for 20 to 30 years or longrr, and such wide range of soil types, they do best on fertile initial costs will be recovered over a period of sandy loam soils, high in organic matter. Deep years. sands or heavy clays may be used, however, if provisions are made for adequate fertilization, LOCATION OF VINEY ARD moisture, and soil drainage. Grapes are tole- rant to a wide range of soil aci

(2) Table 1.-American Grape Varieties for Virginia these hybrids have potential for tatle use and Harvest Date in all yield quite go::id jams and jellies. Their suit- Weeks before ability for wine is due mainly to a flavor pre- Fruit or after ( +) Principal dominantly vinifera in character. Variety Color 1 Concord 2 Use 8 Remarks Of the many French-American hybrids avail- Himrod w 3 T High quality, sus. able, those listed in Table 2 have been sufficient- to black rot. ly tested to be suggested for planting anywhere Seneca w a T Vinifera character- istics pedominate. in Virginia American bunch varieties can be Price B T, J High quality, vigor- grown. ous, productive. Buffalo• B t½ T,J,W High quality, hardy, Fredonia B 2½ T,J Concord type, hardy, Vinifera vigorous. Alc!en B 2 T,W Non-slipskin, high Few varieties of Vi tis vinifera have performed quality. well enough to be recommended for commercial Bath• B 1½ T,J Concord type, hardy. planting in Virginia. Varieties that have per- Monticello B l½ T,J Hardy, high quality, vigorous. formed reasonably well in test plots and home Delaware R J,W Good . plantings include Malaga Bleu, Lignan Blanc, Concord• B fl T,J,W Standard by which Chasselas Golden, and Loenigen der Weingarten. other varieties are In n::irthern wine-growing areas, and in some rated. Niagara* w ,¼ T,W Good wine, sus. to small c::immercial vineyards in Virginia, there is black rot. s::ime limited production of a few vinifera varie- Steuben ll i-1 T, J Concord type, rec- ties for wine. Of these, Johannisberg (White) ommended for E. Va. Reisling and Pinot have been the Catawba* R +1 J,W Popular wine variety. most successful. • Not recommended for Eastern Virginia due to uneven ripening and susceptibility to black rot. The wine varieties of vinifera listed in Table 1 Fruit Color: W-white; B-black or blue; R-red, 3 show sufficient promise to be suggested for 2 Average Concord Ripening Date: Valley and Southwest Virginia -Sept. 10; Piedmont-Sept. 5; Southside and Tidewater-Eept. 1. trial plantin~s in Virginia, subject to the limi- 8 Principal Use: T-table or dessert; J-juice, jam, jelly; W-wine. tations noted.

Table 2.-French-American Hybrids for Virginia Table 3.-Vinifera Varieties for Virginia•

Harvest Date in Harvest Date in Weeks before Weeks before Fruit or after ( +) Wint:: Fruit or after ( +) Wine Variety Color 1 Concord 2 Color a H.emarks Variety Color 1 Concord 2 Cofor 3 Remarks Aurora w 2 w Good table grape, Pinot Nair B R ModerAte in vigor, (S-6279) hardy. vigorous. pro- hardiness, produc- ductive tivity. l! 1½ R Hardy, vigorous. Gewurztraminer W w V igorouR, produc- (S-13063) productive. tive, moderate In Foch B R Hardy, med. vigor, hardiness, (Kuhlmann average production. Pinot 188-2) Chardonnay w w Excellent wine; DeChaunac ll ¼ R Hardy. produC?tive. moderate in hardi- (S-95,9) average vigor. ness, vigor. pro- Saco Nair ll ½ R Extreme:y vigorous, ductivity, (Baco #1) small clusters, hardy. White Reisling W w Best for most Vir- Leon Millot B ½ R Hardy, productive. ginia conditions. (Kuhlmann disease tolerant. Vigorous, productive, 194-2) moderately hardy. Chancellor B II R Very productive. Cabernet (S-7053) hardy, vigorous. Souvignon B +1 R Excellent . Seyval w +½ w Very good wine, sus. Moderate in vigor, (SV-6276) to disease, medium hardiness. produc- vigor. tivity. Vidal w +½ w Vigorous, productive. (V-266) promising. * Rigorous spray schedule required in humid areas because of sus- Villard Blanc w -t-1 w Good table grape, ceptibility to fungal diseases. Subject to winter injury in areas of (SV-12375) hardy, vigorous, frequent low temperatures. productive. 1 Fruit Color: W-white; B-black or blue, • Average Concord Ripening Date: Valley and Southwest Virginia 1 Fruit Color: W-white; B-black or blue. -Sept. 10; Piedmont-Sept. 6; Southside and Tidewater-Sept. 1. 2 Average Concord Ripening Date: V"lley and Southwest Virginia 3 Wine Color: W-white; R-red. -Sept. 10; Piedmont-Sept. 6; Southside and Tidewater-Sept. 1. • Wine Color: W-wbite; R-red. Muscadine French-American Hybrids As the muscadine grape, Vitis rotundifolia, Most of the French-American hybrid grapes cannot be grown successfully where tempera- have been introduced since World War II. They tures go lower than 10° F., production in Vir- were developed from crosses of the European ginia is limited to the southeastern portion of grape, Vitis vinifera, with one of the American the state. The selection in Table 4 from the nu- species, primarily V. rupestris and V. lincecumii. merous named varieties available has been made Although developed as wine grapes, some of on the basis of adaptability to Virginia grow-

(3) ing conditions, the vigor and productiveness of Monticello (VPI 31) - In grape areas north the vine, and the quality of the fruit for eating of Virginia, Monticello promises to be a replace- and for use in jams, jellies, juice, and . ment for Bath. Ripening about 10 days before Concord, it is of average vigor and much above Table 4.-Muscadine Grapes for Virginia average in productivity. It needs cluster thin- Approx. Ripen- ning to prevent over-bearing. The berries are Fruit ing Date Principal blue-black in color, of medium size, slipskin, and Variety Color Eastern Va. Use 1 Remarks not subject to cracking. It runs high in sugars Hunt Black Sept. 20 J,W Vigorous, productive, and is very good as a table grape as well as in wine quality fair, sus. to bitter rot fungus. jams and jellies. Its wine qualities are only fair. CarloF; '~ Bronze Sept. 20 W,J Excellent white wine, Century I (VPI 32) - A variety of the non- very productive, vig- slipskin type, the quality of Century I is rated orous, moderately at least equal to that of any California-grown hardy. 8cuppernonll Bronze Sept. 20 J,W Very good white grapes found in Virginia markets. The clusters wine; moderate in are large, usually well-filled with large, ovate, vigor, hardinesi:- reddish-black berries. It ripens with Concord, and productivity. depending upon the load of fruit the vines car- Magno1ia • Bronze Sept. 20 W,J Excellent white wine, vigorous, relatively ry. The crisp, meaty flesh has a flavor dis- hardy, productive, tinctly of the vinifera type, sweet and fruity. subject to fungu.s The vines are average in vigor and overly pro- diseases. ductive. They must have close pruning and clus- Tarheel • Black Sept. 20 W, J Excellent bunrnndy type wine, very vig- ter thinning to prevent overbearing, resulting orous, moderately in winter injury to the wood. The fruit and hardy, sus. to pow- foliage are subject to black rot and powdery dery mildew. mildew, requiring disease control measures typi- • Perfect flowered. Other varieties are pistillate and require pol- linizers. cal of vinifera grapes grown under eastern cli- 1 Principal Use: J-juice, jam, jelly; W-wine. matic conditions. The vine is medium hardy to winter cold unless allowed to overbear.. Virginia Introductions The following varieties resulted from the grape PROPAGATION breeding program at VPI&SU. Two, Price and Most growers prefer to buy their plants from Monticello, have already found a place in com- commercial sources, but grapes may be propa- mercial vineyards. in the eastern grape growing gated easily and at little expense by the average region of the United States. grower with a "green thumb" and a little time. Alwood (VPI 5-2) - This variety ripens about 2½ weeks before Concord. The vine is of me- Cuttings dium vig'.:>r and productivity. The clusters are Most varieties of American bunch grapes and of medium size, and the medium-size berries are French-American hybrids are grown on their own blue-black in color, with a heavy waxy bloom. roots. These are usually propagated from hard- The berries ripen uniformly and are not as sub- wood cuttings of the previous year's growth. ject to uneven ripening in the warmer areas of The wood for cuttings can be taken from the the state as those of Concord. The fruit and vines any time after the leaves have been shed foliage is only moderately susceptible to the nor- by the vines in the fall. Unless facilities are mal grape diseases - black rot. anthracnose, available for storing the wood under conditions downy mildew, and powdery mildew. that will protect it against drying out or severely Moored (VPI 26) - Moored has large com- low temperatures, it may be better to leave the pact clusters of medium-red berries, ripening wood on the vine until late winter or early spring. about 3 weeks before Concord. The vine is Wood of medium diameter and medium vigor, much above average in vigor and productivity. as shown by the length of the wood between The skin is of the slipskin type, medium in thick- the buds or nodes, usually roots more readily ness and toughness. The fruit is above aver- than wood of small or larger diameter. Wood age in firmness and withstands normal picking of excessively long growth between the buds is and handling operations without damage. Flavor more inconvenient to handle in the nursery or is somewhat "foxy" when allowed to become over- propagating beds. ripe. Susceptibility to black rot and mildew is Varieties of the Concord-type root readily from only moderate. cuttings of three buds in length. Varieties with Price (VPI 30) - A 1972 introduction, Price short growth between buds (like Delaware) will has already been accepted as a commercial vari- root equally well from three bud cuttings, but ety of promise in eastern grape growing areas. such short cuttings may be less convenient to Ripening about 3 weeks before Concord, it is handle than longer cuttings. If vines of new or a good variety for eating fresh and in jellies and scarce varieties are to be propagated and the jams. The red- is of on!y fair qual- supply of wood is limited, cuttings of two buds ity. It is less subject to black rot, mildew, and can be used, but special care and the use of skin cracking than most varieties. The vines greenhouse or cable-heated beds may be advis- are of moderat:e vigor and productivity. able to favor rooting of the cuttings. (4) The bottom ?r ba~~l cut is usually made just Layering below a bud with a square" or right-angle cut. The upper cut of each cutting is usually made at If a vine dies in the vineyard it can be re- an angle or slope so that when the cuttings are ~l~c~d by_ "layering" a new vin~ from an ad- placed in the propagation bed or nursery none J ommg vme_. . ~his ~onsists of bending a cane ~ill have the bottoms and tops reversed.' Cut- from an adJommg vme to contact the soil and tmgs placed upside down usually do not grow ?overing several buds or leaf nodes with 3 or 4 well. mches of soil at the site where the new vine is The cuttings are usually tied in bundles of 25 to be located. This can be done in late winter or 50, using a rot-resistant twine if they are or early spring with a cane of the preceding not to be planted at once. Each bundle should year's growth or in midsummer with a cane of b~ carefully and accurately labeled as to variety, the current season's growth. In either case the with the date when the cuttings were made. buried shoot or cane will strike roots at the' site They can ~e stored, while awaiting planting, in o~ the buried buds or leaf nodes. New shoots a well-dramed trench on the shadv side of a will grow from the buried buds and by the end building or other structure, in a cool cellar, in of the first season of growth a well-rooted a household refrigerator, or in refrigerated cold should have developed from the layered (buried) storage not being u~ed for fruit storage. The cane. The following spring, the cane connecting bundles of cuttings should be covered with moist the layered plant to the original vine should be (but not wet) soil, sand, sawdust, shredded peat. cut and the newly layered plant allowed to de- or other material to prevent them from drying. velop independently. It should then be pruned If the cuttings are to be rooted in a nursery, and trained like a newly set plant. they should be planted in earlv spring about Most muscadine varieties are difficult to root the time earlv ve~et

GROUND LINE

Figure 3.-Methods of bracing end posts of the threllis. Left: double bracing where rows are long. Right: (A) Inside brace against short posts. This type is usually most satisfactory. (B) Outside wire brace anchored with a stake driven in the ground. This type may interfere with the turning of cultivation and spraying implements at ends of rows. the wires to the posts loosely enough to permit restretching each winter. Fasten the wires on the sides of the posts toward the prevailing wind or on the outside of curves in contoured rows, Figure 2.-Planting and pruning the young grape. in order to lessen the strain on the staples.

(6) TRAINING SYSTEMS is produced the third summer. The vine usu- Pruning can be done faster and by less experi- ally is fully grown after the fourth year from enced workers when a definite system of train- planting. ing is followed. Conventional training of east- The six-arm Kniffin system permits more ern grapes has been to the Kniffin system. Three canes to remain on the vine by tying them to modifications of this system are in current use each of 3 trellis wires. Both systems stand- - the 4-arm Kniffin, 6-arm Kniffin, and the ardize the training procedure for routine prun- umbrella Kniffin. Two new systems of training, ing and handling of the vine. the single curtain cordon, and the Geneva dou- ble curtain, are worthy of consideration by the Umbrella Kniffin commerical grape grower in Virginia. They are The Umbrella Kniffin is somewhat like the adapted to mechanical harvesting and vines of 4-arm and 6-arm Kniffin systems except that high vigor. Better maturation and increased all of the fruiting canes grow near the top wire. yield are possible by shoot and foliage position- A single trunk is headed about 6 inches below ing which exposes a greater proportion of the the top wire and new canes are allowed to grow leaf area to sunlight. from this head. Two to six fruiting canes are bent over the top wire and tied to the bottom Four-arm Kniffin wire in the shape of an umbrella ( Figure 5) . The single trunk, 4-arm Kniffin system con- sists of a permanent trunk of old wood reaching to the top trellis wire. There are 4 semi-perma- nent arms, 6 to 10 inches long, 2 extending in opposite directions on each trellis wire. New canes arise near the base of the arms each sum- mer, one cane being left on each arm to bear fruit the following summer. Another cane on each arm is cut back to a short stub with 2 buds. This stub is called a "renewal spur". Figure 4 illustrates the successive steps to be followed in training young vines to this system. The young vines will be weakened if they are permitted to bear heavy crops of fruit during Figure 5.-Grape vine trained to the Umbrella Kniffin the second and third summers. A partial crop System. A

T

~------(1) (2) (3) (4) Figure 4.-Stages in training the young vine to the single trunk, 4-arm Kniffin system. (1) After pruning the first winter. The single cane is cut back and tied to the lower wire. If the cane has grown less than 3 feet during the first summer, it should again be cut back to two buds. (2) After pruning the second winter. Two new canes of four or five buds each are tied on the bottom wire. A third new cane is tied to the top wire and cut off. (3) After pruning the third winter. Three of the arms (A) and the fruiting canes (B) have been formed. A cane (C) with four or five buds is left to establish the fourth arm. (4) A fully formed vine after pruning the fourth winter. The arms (A) should be shorter than those shown. T-single permanent trunk; A-four semi-perm,ment fruiting arms; F-four annual fruiting canes; S-four renewal spurs with two buds on each. (7) Leave enough buds on all canes so that each Two main trunks from each vine extend ver- vine has a total of 40 to 50 buds, depending tically 5½ feet and then horizontally to the cor- upon the vigor of the vine. don wire, a distance of 2 feet. A wire strung down the row and secured near the middle of Single Curtain Cordon the posts will aid in supporting the trunks. A The single curtain cordon training system is single trunk which separates at the cordon wire, developed on a standard 2 or 3 wire trellis used as in the case of the Single Curtain Cordon for training to the Kniffin systems. It is suit- shown in Figure 6, may be used instead of the able for vines of low to moderate vigor, gives double trunk if desired. the advantage of greater exposure of the foli- Cordon canes extending 6 to 8 feet along the age to sunlight, and is adapted to mechanical cordon wire in each direction are secured to the harvesting. wire by semi-permanent ties. Five-bud fruiting As shown in Figure 6, the single trunk is canes and one-bud renewal spurs are maintained trained to the top trellis wire approximately 6 on each cordon. The growing shoots are posi- feet from the ground. Two horizontal cordons tioned by hand so that they will grow in a ver- are developed along the top wire, extending 4 tically downward direction to form a curtain of foliage suspended from each cordon wire. The final effect is a double curtain of foliage from each row of grapes.

,\ COIOOH wltf su,,01 I COIOON WIH (" COIOON 0 flUITING CANI C lfNfWAI s,utS

,osrs ••t s, ... no .-. , ,,

Figure 6.-Grape vine trained to the Single Curtain Cordon System. feet in each direction. Initially, cordons are secured to the wire by plastic ties or other simi- lar material. As the cordons are actually ex- -ii.:.~·. tensions of the trunk, they are semi-permanent Figure 7.-The Geneva Double Curtain System of Train- and by giving them 1½ turns around the wire ing. will remain in place without annual tying. Like (Courtesy, Dr. Nelson Shaulis, New York Agricultural Experiment the Geneva Double Curtain system, 5-bud fruit- Station) ing canes and 2-bud renewal spurs are selected from each cordon. Shoots are later positioned TRAINING YOUNG VINES downward for maximum exposure to sunlight Regardless of the training system to be fol- and to facilitate harvesting. lowed, young grape plants are handled alike during the first season in the vineyard. Most Geneva Double Curtain growers cut back to 2 strong buds at planting. The Geneva Double Curtain system of train- Some prefer to leave a longer cane of 8 or 10 ing is recommended for vineyards with above buds and allow only the 2 uppermost buds to average vigor - those producing 3 or more develop into shoots. This often permits the new pounds of prunings per vine. Although devel- shoot to grow to the top of the stake or trellis oped for the Concord variety, it has been used more quickly. A stake 4 or 5 feet high driven effectively for other vigorous varieties of both into the ground near each vine is used to train the American and French-American hybrids and the vine during the first growing season. is recommended for the vigorous growing mus- Before pruning the second spring, a system cadine varieties. It has proven superior to other of training should be decided upon. Primary systems in use, increasing vine productivity and consideration of all training systems is the estab- at the same time improving fruit and vine mat- lishment of a vigorous, straight trunk. Remove uration. all but the best single cane during the second As shown in Figure 7, two horizontal cordon dormant pruning. Two trunks may be left for wires are separated in the row by a distance of training to the Geneva double curtain system. 4 feet and are at a height of 5½ to 6 feet above Also, in the case of the tender vinifera varie- the ground. The wires are held in position by ties, a second trunk gives added insurance of wood or metal supports attached to each pcRt vine survival under adverse weather conditions. spaced 24 feet in the row. Tie the cane Recurely to the uppermoRt wire

(8) that it will reach and more loosely to the lower wire, then cut it off just above the upper tie. If a cane is weak and does not reach the lower wire of the trellis, cut it back to 2 or 3 buds and treat as a newly planted vine. PRUNING MATURE VINES Fruiting Habits of Grapes In order to prune properly, the fruiting habits of grapes must be understood. Grapes are borne on new fruiting shoots that grow in the spring from buds on 1-year-old canes. Each cane has a number of joints, or nodes, and at each node there is a bud. Fruiting shoots grow from these buds in April. These shoots usually bear two to four blossom clusters that open in late May and early June. Fruit forms on these clusters and is picked in August or September. If spring frosts kill the first fruiting shoots, then the compound buds develop secondary shoots which may pro- duce a partial crop.

Time of Pruning Pruning is best done in late winter. In large vineyards, it may start as soon as the vines become dormant in early winter and continue Figure 8.-Fruiting habit of the grape vine.

Figure 9.-Grapevine before and after being pruned to 4-arm Kniffin system. during mild weather until spring. There ap- For vines trained to the 4-arm Kniffin sys- pears to be no danger of winter injury follow- tem, follow 3 pruning steps: ing early pruning. Pruning after the sap be- 1. Select four canes of wood, one on each gins to flow does not injure the vines. arm, to bear fruit the following summer. These canes should be about 4 to 6 feet long and about Severity of Pruning the thickness of a lead pencil or slightly larger. Grapevines should be pruned rather heavily Preferably, the canes should grow from the base each year. Most pruners tend to remove too lit- of the arm near the trunk. If no cane is to be tle wood, rather than too much. Proper prun- found on an arm, then select a cane that grows ing regulates the amount of vine growth and the directly from the trunk near the arm, although number, size, and compactness of fruit clusters. it may not be as productive. It also provides for renewing the fruiting canes Shorten these four canes so that 8 to 15 buds each year. Figure 9 shows a Concord vine of remain on each. Leave the strong canes longer average vigor trained to the 4-arm Kniffin sys- and shorten the weaker canes so that a total of tem before and after being pruned. 32 to 48 buds remain on all four canes. Leave (9) fewer buds on weak vines and more buds on and weakening of the vines. An arm is renewed vigorous vines. Leave fewer buds on Portland by selecting a strong cane growing directly from and Delaware and more buds on Fredonia. Ruf- the trunk and shortening this cane to two buds. falo, Concord, and Niagara. Heaviest production As vines become older, it is difficult to maintain of fruit usually occurs at the fifth and ~ixth arms. It may then be best to select canes that buds of Concord canes and relatively less fruit grow directly from the trunk and cut them hack is borne toward the base and the tips of the to one or two buds for renewal spurs. When canes. the main trunk becomes too old or weak to pro- The balanced pruning method is helpful in de- duce profitably, cut it off at the ground and termining the number of buds to be left on the replace it by starting a new shoot from the ba~e fruiting canes. It is based upon the amount of of the vine. Train this new shoot as if it were vine growth during the previom1 summer. Ac- a newly set vine. cording- to this method. weigh thP. new. 1-year In the ca!'e of old vines that have not been wood that has been pr11ned off. This will vary pruned reg-ularly, the canes extencl farther out from 1 to 4 pounds. This wei1rht indicates the Pach .vear. leaving the fru'ting woorl too far ;1wa:v number of bnds to be left on thP four fruiting from the trunk. Man:v Rhort. weak «hoots form canes. For Concord vines, leave 30 buds for the dPnse shade. whi"h causes the inside partR of first pound of new wood rem,wed ancl 10 hncls the vine to die. The<:e old vinPs m!'.lv be re.inYe- for each additional pound. For example, if 2 nated bv prorn pruning- and fntili~ing to bear pounds of new wood has been prunecl off, lf'ave g-oorl crops within 2 years. The first step in 30 plus 10, or 40. buds on the fonr fruitinO' canes. pruning is to f'llt 011t all cle!'.ld and extremely Fredonia renui.res lighter pruning in which 40 weak wood. Then shorten the long trunk and buds are left for the first pound ancl 10 hucls branches so as to le:-we eirrht tn ten of tre strong-- for each additional pouncl of new wood prun- est new <'anes on the vine. Shorten about one- ings. With a little experience. the pruner will hr lf of these new canes so a<.1 to leave six to be able to est'mate the poundc:: of priininp-c:: r::ither eight b11cls on rnnh; Pnt the others b:>ck to one than weigh them for each vine. (See Tables 5 or two buds each. Thi.s heavy pruning stimu- and 6). late.::: the clevelopment of strong new rhoots near- Tahle 5.-Relation of NnmbPr of Rucls Remain;nl!' to er the main trPnk. and. ;it the ~·l'!me time. rro- the WPiJ!'ht of 01'1e-Year Pruning Wood Removed from vides some fruit the next summer. Prune the Vines ~econrl winter so as to thin the TIPW canes and Lbs. of I-Year-Old No. of Burls Left provide renewal spurs. Thereafter. pruning Wood Removed For Fruiting should follow one of the methods that have been Less than 1 Less than 30 discus~ed previously. 1 30 2 40 Tying the Vines 8 50 4 or more 60* Tight wires and nrnner tyin-~ prevent: :::av-ring vines and curved trunks. After pruning, keep • It is recommended that not more than 60 buds be left on a pruned vine. the vines free from thP. tr0 llis unti! the wires have been tightened. Tie the trunk and fruit- Table 6.-Number of Buds to Retain on Concord Vine Trained to Either Single Curtain Cordon or Geneva Dou- ing- canes to the wires with plastic ties. bincler ble Curtain twine. or other suitable material. Thf'se ties should be strong enough to gupnort the vines No. of No. of Total No. Lbs. of I-Year-Old 5-Bud I-Bud Buds for one season but not so durable as to inter- Wood Removed Canes Renewal Spurs Retained fere with brush removal during pruning the fol- 4 10 30 lowing winter. Tie the trunk to both wires loose- 2 6 10 40 ly enough to avoid girdling and tie each fruit- 3 8 10 50 ing cane to the wire at a point near its tip. 4 A 10 10 60* tie about 12 inches long is looped over the wire, • It is recommended that not more than 60 buds be left on a pruned vine. crossed between the wire and the cane. and then tied around the cane. Long canes should be tied 2. Select four other canes, one near the base in two places. of each arm if possible, or wherever they may be found on the trunk near the arm. Shorten Cluster Thinning them to leave one or two buds on each. These Many varieties of grapes set more fruit clus- short stubs are the renewal spurs that provide ters than they can carry to maturity with the new fruiting canes each year. A strong cane highest quality. French-American hybrids fre- will grow from one of these buds and this cane quently set 3 to 5 clusters from each fruitful is used for a fruiting cane for the next year. bud. In varieties where the basal buds are fruit- 3. Prune off all other new growths from the ful, the vine can easily be overloaded even though vine. Remove old tendrils that are twined around pruned severely b short spurs. the vine, in order to avoid girdling. Cluster thinning is the easiest and best means The four arms should be renewed frequently. of reducing the crop on overloaded vines. Enough Very old long arms tend to cause overbearing fruiting wood ghould be left at pruning time

(10) lo produt:e a good t:rop in years of pour set, then pound for mature vines, or 250 to 300 pounds reduce the O\'erload by thinning. Thinning, as per acre. When sulphate of ammonia is substi- sJcn as possible after fruit has set. to 1 or 2 tuted for nitrate of soda, only three-fourths as clusters per shoot is recommended. much will be needed. Only one-half as much ammonium nitrate is required since it contains SOIL MANAGEMENT twice as much nitrogen as nitrate of soda. The Cultivation standard recommendations of 10-10-10 or 5-10-5 Cultivation is necessary for young vines and fertilizers, applied when the winter cover crops also for most older vineyards. It should begin are planted, usually will add enough phosphorus in the spring and continue until about 1 month and potash to the soil to provide for the needs before the fruit ripens. A winter cover crop of of the grapevines. If 10-10-10 fertilizer is ap- rye or other winter-hardy small grain mav be plied for the benefit of the cover crop, the spring planted between rows. Disking in the spring application of nitrogen for the vines may be re- should be delayed until such time as the grow- duced by one-fourth to one-half. For young ing cover crop starts to compete with the vines vines, scatter the fertilizer in a circle around the for soil moisture and nutrients. The longer the plant. For mature vines, spread the fertilizer cover crop is left, the more organic matter will evenly over the entire area since the grape roots he added to the soil. occupy practically all of the space between the If no cover crop is planted, a natural cover rows. Weeds are less troublesome if little or of fall weeds and grasses should be allowed to no fertilizer is placed directly under the trellis. grow and cover the ground during the winter. Skillful vineyardists vary the annual amounts Cultivatwn should be shallow and frequent of pruning and nitrogen fertilizer to balance the enough to check the growth of competing weed:;; amount of vine growth and fruit yield. When and grasses, hut not so frequent or thorough vines have been weakened by overbearing, drouth, as to kave the soil entirely bare. Clean culti- or loss of leaves, they need heavier pruning and vation will cause soil erosion and loss of organic more nitrogen fertilizer than usual. On the matter. other hand, excessive vine growth resulting from Effective implements include a light disk har- a light crop or from highly favorable growing row for use between rows; a garden tractor cul- conditions during the preceding year, calls for tivator of suitable power to be used along the less pruning and smaller amounts of fertilizer. sides of the row ; and a hand or tractor hoe for Normally, a vine is considered weak when the removing weeds between vines. Do not use turn- new canes are less than 3 feet long. Canes 10 ing plows in bearing vineyards because they feet or more long usually indicate too much vine injure too many roots. A convenient implement growth. These figures will vary considerably, is the tractor hoe with an adjustable scraper and the grower's experience will be his most re- blade to turn the soil alternately toward the liable guide. rows during one cultivation and away from the PEST CONTROL rows the next. The tractor driver moves the blade in and out between vines, thus eliminat- Black rot is the most destructive disease among ing much hand hoeing. grapes in Virginia. Carried over the winter on Maintaining a permanent sod cover between old canes, leaves, and dried grapes, this disease vineyard rows may be desirable under certain infects the leaves early in the spring. Unless conditions. It should be mowed frequently, leav- controlled, infection quickly spreads to new ing the clippings on the vineyard floor. Some shoots, other tender parts of the vine, and then reduction in yield due to competition for mois- to the developing fruit. The fruit rots, becom- ture may he experienced, particularly on light- ing black, hard, and shrivelled. Black rot is espe- er soils. cially troublesome in wet seasons. The use of chemicals for weed control in vine- Downy mildew also thrives during wet, cloudy yards is very effective and frequently less ex- weather. The foliage of Delaware and the fruit pensive than cultivation. Herbicides must be of Fredonia are very susceptible to this disease. used with caution, however. Grapes are very It first appears as yellowish spots on the upper ~·ensitive to mirnse. Contact vour local Exten- surface of the leaves, followed by white cottony sion agent for the latest recommendations. patches on the lower surface. These spots later turn brown. Severe infection results in prema- Fertilization ture loss of the foliage, withering of the fruit Grapevines respond to commercial fertilizers and stems, and weakening of the vines. according to the kind of soil and its natural Anthracnose causes oval, sunken spots to ap- fertility. Practically all vineyards should re- pear on the surface of new shoots, stems, and ceive an annual application of nitrogen fertilizer leaves, with round gray and red spots on the such as nitrate of soda, sulphate of ammonia, or developing fruit. Where the infection is severe, ammonium nitrate. These fertilizers stimulate heavy foliage and fruit loss may result. An- plant growth and increase yields. Fertilize early thracnose is more severe in hot climates than in in the spring before growth starts. If nitrate cool areas. of soda is used, an average vine will need about Leaf hoppers and the grape berry moth are 2 ounces for each year of age up to one-half the major insect pests.

(11) For current recommendations on the chemical high as 8, 10, and even 12 tons per acre. The control of insects and diseases of grapes, con- average is somewhere around 4 tons, however. tact your local Extension agent. Viniferas have in some instances been reported to yield as high as 10 tons, with the range some- HARVESTING what lower - between 2 and 5 tons. Some mus- Time of Harvest cadine varieties have yielded 7 tons, with the The proper time to harvest grapes depends average between 2 and 6 tons. upon the variety, growing season, and use to be Method of Harvesting made of the fruits. For table use, maturity is usually determined by taste or by the color of Although most grapes are now hand harvested, the , which changes from green to brown. mechanical harvesters have been developed and Skin color is not always a reliable test for ripe- are being used in large commercial vineyards ness, as some blue varieties color before they have for harvesting processing grapes. developed their best flavor. Both blue and red Vines trained to the single curtain cordon and grapes should be completely colored around the the Geneva double curtain systems are particu- stems when they are ripe. larly adapted for mechanical harvesting. For juice or wine, the harvest date is deter- Grapes for fresh market use should be picked mined on the basis of the percentage of soluble and handled carefully. It is usually necessary solids as measured by either a refractometer or to pick at least twice to allow for full ripening a Balling hydrometer. Processors prefer grapes of all clusters. Each cluster is cut from the vine that contain at least 15 % soluble solids. An with a knife or special sharp-pointed shears. increase in soluble solids above 15 % is usually They are frequently packed directly into contain- reflected in an increased price per ton. ers as they are picked. Portable picking stands As grapes do not improve in color or sugar about 30 to 36 inches high on which to set the content after removal from the vine, where pos- baskets are convenient. sible, harvest should be delayed until most of Muscadine varieties bear the fruit in small the berries are fully ripe. For fresh use, the clusters of 4 or 5 to a dozen berries. The fruit clusters are harvested selectively according to usually is not harvested by gathering clusters, the degree of maturity. For commercial proc- but by placing a sheet or catching frame under essing, the entire crop is harvested at one time. the vine and shaking it vigorously to separate the ripe berries from the clusters. For proc- Yields essing, muscadines may also be harvested me- Although a partial crop may be expected the chanically. third season after planting, full bearing capac- Handling and Storage ity will not be reached until the fifth or sixth year. The productive life of a vineyard ranges As soon as possible after harvest, grapes should from 20 to 30 years or longer, depending on the be removed from the vineyard and placed in care given the planting and suitability of the site. shade or storage. If the fruit cannot be moved Under Eastern growing conditions yields are directly to the consumer or processor, it may quite variable, being affected by variety, prun- be held in storage. Ideal storage conditions for ing and training systems, cultural practices, de- grapes are similar to those for apples - a tem- gree of pest control, and climate. American and perature of 30° to 34 ° F. and a relative humidity French-American hybrids frequently yield as of 85 to 95%.

(12) A Guide for Virginia Costs of Establishing Table Grape Vineyard at 1976 Prices*

Variable Cost Quantity Cost Unit Cost per Acre per Acre

Land Preparation Diesel Tractor, 57 H.P. hour 1.82 .80 1.46 Plow, 2-16" hour .60 .80 .48 10-10-10 fertilizer ton 140.00 .20 28.00 Agricultural lime ton 12.00 2.00 24.00 Operator labor hour 3.50 .88 3.08 Hole Digging Diesel tractor, 57 H.P. hour 1.82 43.52 79.23 Tree auger hour .20 43.52 8.70 Unskilled labor hour 2.50 47.87 119.68 Operator labor hour 3.50 47.87 167.55 Planting Gas tractor, 57 H.P. hour 2.19 27.20 59.58 Two wheel trailer hour .12 27.20 3.26 Table grape vines, 1 year each .60 544.00 326.40 Unskilled labor hour 2.50 59.84 149.60 Operator labor hour 3.50 29.92 104.72 Watering Tank truck hour 1.26 1.00 1.26 Operator labor hour 3.50 1.10 3.85 Post Setting Gas tractor, 57 H.P. hour 2.19 21.76 47.67 Diesel tractor, 57 H.P. hour 1.82 21.76 39.61 Two wheel trailer hour .12 21.76 2.61 Post driver hour .13 21.76 2.89 Posts, 3" tip, treated each 2.00 272.00 544.00 Unskilled labor hour 2.50 47.87 119.68 Operator labor hour 3.50 23.94 83.78 Wire Installation Gas tractor, 57 H.P. hour 2.19 8.00 17.52 Portable Drill hour .065 8.00 .52 Wire (no. 9) foot .0225 9,712.00 218.52 Unskilled labor hour 2.50 17.60 44.00 Operator labor hour 3.50 8.80 30.80 Interest on operating capital dollars .08 2,232.46 178.60

Total of Vineyard Establishment 1 ------$2,409.82

• With permission of Dr. J. M. Johnson, Extension Specialist, Marketing, Department of Agricultural Economics, VPI&SU. 1 Exclusive of growing operations including pest control chemical and spray equipment. 2 Figures may not be exact because of rounding errors.

(13) Virginia Cooperative Extension Service programs, activities, and employment opportunities are available to all people regardless of race, color, religion, sex, age, national origin, handicap, or political affiliation. An equal opportunity/affirmative action employer.

Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, and September 30, 1977, in cooperation with the U.S. Department of Agriculture. W. R. Van Dresser, Dean, Extension Division, Cooperative Extension Service, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061; M. C. Harding, Sr., Administrator. 1890 Extension Program, Virginia State University, Petersburg, Virginia 23803.