Growing Grapes in WV - West Virginia Department of Agriculture

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1. The fruit is borne onshoots produced from oneyear-oldwood. One-year-oldwood is brown, reddish-brown,or gray, depending on thevariety, and the bark is tightand not peeling. The amountof wood older than one yearshould be kept to a minimum toform the framework for holdingthe fruiting wood.2. Severe pruning resultsin an excess of wood and littlefruit, although both berries andclusters will be large. Lightpruning results in the productionof little wood and a largenumber of small clusters ofsmall fruit. A balance betweenwood and fruit production isdesired to give a good cropof large clustered fruit andenough wood for good canesthe following season. The numberof buds to leave is cultivardependent. For most cultivars30 buds should be left for thefirst pound of one-year-oldwood prunings removed and10 buds left for every pound ofprunings after that. If you remove3 pounds of one-year-oldwood, then there should be 50buds left on the vine. These 50buds may be ten 5-bud spursor five 10-bud canes dependingon your training system.This allows a balance that willvary with the vigor of the plant.To do this, most of the woodis removed, leaving more thanyou think should be left. Afterweighing what has been taken-12-off, the buds remaining canbe counted and more woodpruned off to adjust the numberof buds remaining to fit the balancedpruning equation.3. The best canes to keepfor fruiting are those of mediumsize (about the size of a pencil)with plump buds. Canes with adiameter of one-fourth to onethirdinch and an internodallength of five to eight inches(internode lengths are shorteron vinifera and French hybridcultivars)-both measured betweenthe fifth and sixth nodesfrom the base - are consideredideal.4. The most productivebuds on the canes are cultivardependent, but generally thethird to ninth buds will produceshoots with the most flowers.5. The bearing wood shouldbe close to the main trunk.This saves space and limits theuptake of plant food by unfruitfulwood. Choose wood andrenewal spurs (canes prunedto 2-3 buds to provide canesfor fruiting the next year) closeto the permanent training structure.Permanent structuresinclude the main trunk andbranches (short arms or longcordons) that the fruiting woodoriginates from.Flower-ClusterThinningFlower-cluster thinning is theremoval by hand of some of theflower clusters on each shoot to
control crop load. This is mosteffectively done when the clustersfirst appear. Clusters are removedto increase the vigor of very weakvines and to reduce excessivecrops on vigorous vines. Early reductionin crop load will allow theremaining fruit to be larger, ripenearlier and have higher sugarsthan fruit on over cropped vines.Clusters are usually thinned toone cluster per shoot.Growth regulators are alsoused to control fruit size. Gibberellicacid is a natural plant hormoneusually produced by seeds. Mostseedless grapes respond togibberellic acid with an increasein berry size. In some cultivars,such as Canadice, the increasedberry size can result in excessivecompactness and berry cracking.Concord seedless also reactsunfavorably. Gibberellic acid isapplied at mid bloom and at fruitset, usually about 7-10 days afterbloom, to reduce berry numberand increase berry size.Seeded grape cultivars mayrespond to gibberellic acid withreduced cluster compactness andtherefore a reduction in bunchrot in cultivars with very compactclusters. In seeded grapes,gibberellic acid is applied whenshoots are 4 to 6 inches long.Consult the label before use becausesome seeded cultivars varyin their response to gibberellicacid. Misapplication of gibberellicacid can result in increased winterdamage and reduced bud fruitfulnessin the year following application.Label recommendationsshould be strictly followed.SystemsThere are many different waysto train grape vines. Research andexperience have shown that theJudson River umbrella or Genevadouble curtain are best for mediumto large vigorous vines of Concordand similar varieties. Four armKniffin, cordon and other trainingsystems are acceptable for smallervines. In choosing which system,several considerations should bekept in mind. Vines that are trainedon two wires, one above the other,will have less growth and loweryields on the lower wire becauseof shading from the canes above.Renewal spurs should be in highlight environments to produce goodcanes for the next year's crop.Cultivars with large leaves anddrooping shoots, such as Concord,Niagara, and Fredonia, should havethe head or renewal area of the vineat the top wire to get the best lightexposure. Cultivars with uprightshoots and small leaves can bettertolerate having the renewal areaat the middle wire of a three-wiretrellis because there is less shading.Cane bending as used in umbrellaKniffin will increase bud break alongthe canes or vigorous vines, butshould not be used with weak vinesof any cultivar. In all systems, thefoliage should be uniformly distributedalong the trellis and over itsfull height to a depth of not morethan one and one-half to two layersof leaves for effective exposure tosunlight.-13-
Page 1: Growing GrapesIN WEST VIRGINIAW e s
Page 4 and 5: Locating the VineyardProper site an
Page 6 and 7: Table 2. The expected ten-year freq
Page 8 and 9: for filling in vacancies in anestab
Page 10 and 11: or medium vineyard is to use awire
Page 12 and 13: weeds controlled with herbicides.Th
Page 16 and 17: Geneva Double Curtain:This system u
Page 18 and 19: -16-
Page 20 and 21: HarvestingGrapes should be picked w
Page 22 and 23: are wormy at harvest time. It is ad
Page 24 and 25: Table 3. Summary of grape cultivar
Page 26 and 27: Table3C. Wine CultivarsProductivity
Page 28 and 29: Appendicesw Weather stations are of
Page 30 and 31: Appendix 1a. continuedw x yStation
Page 32 and 33: Appendix 1b. continuedw x y zStatio
Page 34 and 35: Appendix 1c. continuedStations w x

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