Big Vines And Cold Injury Shape Vineyard Management In Virginia

Tremain Hatch

Tremain Hatch

All growers face challenges presented by the environment in which they farm. These challenges shape the agricultural operations within a region. Winegrape production in Virginia is no different. The principal challenges are rainfall during the growing season (approximately 45 inches annually) and the potential for cold injury (both during vine dormancy and spring shoot development).

Keeping the vines alive is dependent on both site and variety selection in this harsh environment. Sites on convex land forms with high elevation relative to the surrounding area are optimum in this environment. The convex landforms promote drainage of cold air and moisture away from the vineyard to surrounding low lying areas. Virginia growers select varieties for moderate cold hardiness and loose cluster architecture with thick berry skins. ‘Cabernet Franc,’ ‘Petit Verdot,’ and ‘Petit Manseng’ are great varieties to grow in Virginia.

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A surplus of water is made available to the vines in fertile, fine-textured deep soils. This water, coupled with warm growing seasons, leads to vigorous vegetative growth, often in excess trellis space and of how much is necessary to produce and ripen the crop. The excessive vegetative growth, coupled with humid conditions, creates conditions in which foliar fungal pests can thrive. Dense shaded canopies that often develop with vigorous vines mush be remediated to open canopies.

While all grapevine training systems share common objectives, the means by which these objectives are met will differ by environment.

Intercept More Sunlight

Most frequently vines are trained to vertical shoot positioning (VSP). Keep canopies open rather than congested through shoot thinning, shoot positioning, leaf pulling, and hedging, even though they represent many labor hours of canopy management every growing season. Open canopies allow leaves to intercept direct sunlight, promote air circulation around leaves to accelerate drying, and increase spray coverage.

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A minority of vineyard acreage in Virginia utilizes divided canopy training systems such as Lyre, Geneva Double Curtain, and Smart-Dyson training systems. There are multiple advantages of these divided training systems.

For vigorous sites, a grower can use the excess vegetative growth to produce and ripen fruit rather than removing this growth with remedial canopy management. Additionally, the divided training systems help limit canopy congestion. Single or divided canopies are often hedged at least one time through the growing season.

Convex landforms in Virginia are advantageous for grape growers as shown at this summer vineyard meeting. (Photo credit: Tremain Hatch)

Convex landforms in Virginia are advantageous for grape growers as shown at this summer vineyard meeting. (Photo credit: Tremain Hatch)

Facilitate Movement Of Equipment
The majority of our vineyards use relatively wide row spacing – less than 9 feet – to allow older, larger equipment through the vineyard. Productivity per acre increases with more narrow rows and some growers are installing vineyards with 7 feet between the rows.

Shoots often grow to 4 feet or longer in Virginia conditions. Usually Virginia growers have VSP-trained vines with a fruiting zone at about 3 or 4 feet above the soil surface. Therefore, the canopy top is often 7 or 8 feet off the ground. Row width allowances for equipment do not frequently create situations in which one row shades the next.

Cordon training and spur pruning are used in older vineyards, especially those with vines spaced 7 to 8 feet apart. Recently, vineyards have been installed with a higher planting density, some going closer than 4 feet between the vines. In those cases, head training/cane pruning is utilized more frequently than cordon training.

Reduce Winter Injury Hazards
Virginia can have winter injury. In the winter of 2013-2014 and the winter 2014-2015, most of the state experienced temperatures at or below 0°F. The moderate winters of the early 21st century preceding these recent winters encouraged growers to plant more cold-tender varieties and plant on sites with more potential for cold injury. These past winters have forced some to relearn old lessons about growing grapes in this environment.
Some growers now are retraining injured vines and incorporating the “spare parts” method into their vine training, retaining more buds and canes at dormant pruning to compensate or prepare for winter injury.

These challenges wine grape growers face in Virginia do increase production costs in a small industry. But the majority of Virginia grape growers make wine from the grapes they grow, adding value to their production because they eliminate the middle man, selling wine directly from their cellar door.

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