California wine grape growers can get sticker shock from expensive vineyard replanting costs which can range from $10,000-$20,000 an acre, depending on the location.

“Replanting has a high degree of costs and risks,” says Toby Halkovich, director of vineyard operations at Cakebread Cellars in Rutherford, Calif.

“Make sure you don’t jump in too quickly, Halkovich suggests. “Replanting is an investment designed to last the next 25-30 years.”

Halkovich’s comments opened a meaty two-hour discussion on wine grape vineyard replanting in California held during the 2013 Unified Wine and Grape Symposium. Halkovich moderated the panel which included several planting veterans and a vineyard financial manager.

The speakers said extend the life of an existing vineyard as long as economically possible and make good informed decisions when it is time to replant.

Vineyard-replant veteran Brad Goehring of Lodi, Calif. (San Joaquin County) discussed the importance of vine nutrition to add vineyard longevity. Goehring, a fourth generation grower, owns and operates Goehring Vineyards, Inc. and Goehring Estate Vineyards.

“There is no substitute for good vine nutrition,” Goehring told the standing-room only crowd. “This means doing things right every time and not cutting corners.”

Good plant nutrition creates a healthier plant canopy which can better endure erratic weather events. Solid plant nutrition can make the difference between harvesting the crop on time versus harvesting after fall rains hoping for a good brix level.

During his career, Goehring has planted about 22,000 acres of wine grapes, mostly in 11 counties in Northern California. Today, he replants about 5 percent to 10 percent of all the wine grape replant acreage in California.

Goehring has seen the basics of California wine grape vineyards change over the decades. About 20 years ago, growers replanted 20-foot-spaced vineyards with mostly sprawl trellis systems with 8-foot to 9-foot row spacing with mostly the vertical shoot position (VPS) trellis system and other exotic systems.

Today, Goehring inches plantings outward to a 10-foot to 11-foot spacing with about a mix of trellis systems — about 50 percent quads, 40-foot sprawls, and 10-percent VSPs or a modified VSP version.

“Some might shake their heads on why we’re still planting VSPs,” Goehring said. “We have some projects as high as 3,500-feet elevation on 55 degree slopes. A VSP or a modified version is very appropriate.”

As growers today face overall replanting decisions, the question is replanting the land with which crop. One of the greatest challenges across California agriculture, Goehring says, is crop competition. About every permanent crop in the state makes good financial sense. Heavy crop competition exists for open ground.

“As a result, sticking with grapes means planting vines in non-traditional areas,” Goehring said. “This creates unique circumstances, including soil pH issues, plus irrigation issues where the elevation from the beginning and the end of the row can vary by 100 feet.”

University of California, Davis viticulture professor and geneticist Andrew Walker also discussed replanting wine grapes. Walker, based in Davis, holds the Louis P. Martini Endowed Chair in Viticulture.

Water becoming politically unavailable

Wine grape growers cannot financially afford to fallow ground for too long between plantings, if at all, Walker says. Un-fallowed ground or not practicing crop rotation can result in severe biological consequences. A partial solution is to rotate grape rootstocks at replant and fallow the ground as long as possible.

How long should a grower fallow ground to decrease pests? Walker says it’s very difficult to remove all pests in a fallowed vineyard.

“It probably is not possible to get rid of all nematodes in a fallow process,” Walker said. In fact, “A short fallow period can largely reduce the population to effectively establish the vines. That is the key.”

Walker then discussed California water supplies and its potential impact on vineyard replanting.

“We will not have enough water in the next 30 years. It (water) will politically become unavailable,” Walker said.

Using overly-weak rootstocks in a relatively dry-and-warm climate is probably not the best strategy in most situations, Walker concluded.

Consultant Stan Grant of Progressive Viticulture, Turlock, Calif., shared several “take-home messages” about vineyard replanting. “Purchase CDFA certified grape vines for the vineyard,” Grant emphasized.

These vines target the elimination of specific grapevine diseases, including leafroll, fanleaf, corky bark, stem pitting, and fleck which can spread from vine-to-vine by grafting and/or vegetative propagation.

Walker’s second, take-home message was, “Replant the vineyard with a rootstock with a different parentage than the previous rootstock.”

This is critical since soil-borne inhabitants in an older vineyard may have adapted resistance mechanisms to the current rootstock.

Conduct a systematic rootstock selection process, Walker recommends. Consider pests issues first, vigor second, followed by other adaptations which could be useful.

Financial planning for replanting was discussed by the ‘banker’ on the panel —Scott Smith, chief financial officer, Silverado Premium Partners, Napa, Calif. The company has vineyards along the California coast.

“My role as a finance manager is (to determine) whether we are maximizing (financial) return from the vineyard,” Smith said. “I am not wedded to which variety is planted. I just want to make money.”

Silverado develops a five-year replanting schedule for vineyards more than 20 years old. The plan is revised annually based on the latest data. Specific vineyards can be moved up the replant schedule or pushed back.

Issues considered include overall vineyard performance, pest and disease challenges, grape quality and yield performance, and if the vineyard has a low net operating income or NOI.

At the end of the day, Smith does not want to remove a vineyard which still makes money or has a customer who really wants the fruit.

Smith concluded, “If you don’t know if the vineyard is profitable or if the variety is profitable, it’s difficult to pull the trigger on redevelopment decisions.”