Plymouth, Calif.—Before irrigation systems became available and practical, dry farming was standard practice for planting and managing wine grapes in California. Dry farming is still possible and successfully used by some growers, but it is site-specific and dependent on annual rainfall, climate, soil type and grape variety. The economics of dry farming are a key consideration in relation to grape yields and prices.

“Dry Farming Winegrapes,” an educational forum jointly organized by the Community Alliance with Family Farmers (CAFF), the Amador County Wine Grape Growers Association and the Lodi Winegrape Commission (LWC) was held April 16 in the Shenandoah Valley of Amador County in California’s Sierra Foothills. Growers here continue to dry farm, where feasible, part of Amador’s 2,000 acres of Zinfandel as it was historically, when grapegrowing began after the Gold Rush. In the Lodi area, LWC grower program coordinator Matt Hoffman estimates less than 100 acres are dry farmed, but growers and winemakers in both Lodi and Amador counties are interested in the potential benefits of dry farming for grape quality and water conservation.

Citing examples of farming operations that had reduced water use for fruit crops and improved quality, CAFF policy director Dave Runsten said, “We’re over-irrigating a lot of crops in California.” He noted that wine grapes have a long history of being dry farmed in Europe and in California and said successful dry-farmed vineyards exist in Sonoma, Napa, Mendocino and San Luis Obispo counties, the Sierra Foothills and Lodi.

Runsten represents CAFF in the California Agricultural Water Stewardship Initiative, a coalition of ag groups with goals to develop and implement approaches to ag water management to conserve water, support sustainable agriculture and protect the environment. The group’s website and the CAFF website have information about dry farming and water-conserving irrigation systems and practices as well as case studies about dry-farmed vineyards throughout California.

Runsten said dry-farmed vineyards in California have some common characteristics and benefits. “Dry-farmed wine grapes are grown on sites that take advantage of deeper soils, and the vines become self-regulating, which can create resilience to drier seasons and heat events,” he said. “These vines produce intensely flavored grapes, and tonnage may be lower (2-5 tons per acre), but they have good quality,” Runsten said. Other factors common for dry-farmed vineyards include: sites with a minimum of 20 inches of annual rainfall, vine planting with wider spacing, the use of drought-tolerant rootstocks and cultivation.

While some dry-farmed vineyards are old vine Zinfandels remaining from historic plantings, or in locations where Zinfandel was traditionally dry farmed, other varieties can be dry farmed depending on location. In North Coast vineyards these include: Cabernet Sauvignon, Carignane, Grenache, Malbec, Merlot, Petite Sirah, Syrah, Chardonnay and Sauvignon Blanc. In some cases, irrigated vineyards have been converted to dry farming.

Amador focus is Zinfandel
Long-time Amador grower Dick Cooper of Cooper Vineyards said it’s still possible to dry farm Zinfandel in Amador if you cultivate and don’t let anything else grow in the vineyard. Since dry-farmed grapes tend to have lower yields, he advised growers to consider the economics. “Generally, given the costs for production in this area, if you’re not producing 4 tons per acre and getting at least $1,500 per ton, you aren’t going to make it,” Cooper said.

Pat Rohan operates a vineyard-management company in the Shenandoah Valley and dry farms two Zinfandel vineyards of 8 acres and 5 acres. He tried mowing rather than cultivating for weed control, but mowing caused soil compaction and reduced rainwater penetration that reduced yields, so cultivation is now standard practice. As with other vineyards, Cooper and Rohan suggested that dry-farmed vines be monitored for stress using tools such as pressure bombs and neutron probes. In some years, they will remove shoots or drop fruit, particularly second crop, to maintain vine balance.

Cooper and Rohan have not had as much success trying to dry farm other varieties in Amador, although in some years, little to no water is needed in some vineyards. Discussing Amador’s other signature variety, Barbera, Rohan said, “When we get three or four days of 100°F heat, we need to water Barbera. When Barbera shuts down, it’s done. In contrast, Zinfandel will shut down and come back.”

Tom Dillian is a fourth-generation Amador grower. He dry farms 20 acres of wine grapes on property his family has owned since 1917. He managed vineyards in Amador County for 40 years, including other dry-farmed vineyards, but now he focuses on his own vineyard and winery, Dillian Wines, established in 2003. Dillian emphasized the importance of site conditions: “My location is great for dry farming. I have very deep loamy soils with super moisture-holding capacity—and with very few rocks, that makes this site very different from most of the Shenandoah Valley.” The site has an average annual rainfall of 30 inches and cooler temperatures than nearby vineyards. Dillian’s Zinfandel harvest is one of the latest in the area, in mid- to late-October. Dillian planted a block of own-rooted, head-trained Zinfandel in 1972 with no irrigation. Since 1978, other blocks of Zinfandel, Primitivo, Barbera and Syrah have been planted with drip irrigation to start the vines. Those drip lines were left in place to use if needed during dry years, but Dillian hasn’t irrigated any vines since 2008. Later plantings use drought-tolerant rootstocks—St. George and 110R, and all vines are head-trained.

Rather than dry farming, Dillian calls his practices “moisture management.” In normal or less than normal rainfall years, everything is cultivated to allow moisture to penetrate deeper for the vine roots. Higher rainfall years provide excess moisture for the vines, and native cover crops are left to grow to take up moisture, then every other row is cultivated later in the spring. Dillian said yields range from 2.5 to 4 tons per acre based on the season, but in 2012 yields approached 5 tons per acre, which he believes is about the upper limit for best quality.

Tim Holdener, owner/winemaker for Macchia winery in Lodi, owns no vineyards. Holdener buys grapes from dry-farmed vineyards in Lodi and Amador, and he works closely with these growers to obtain quality Zinfandel that he turns into award-winning wines. He said, “Grapes from dry farmed and deficit-irrigated vineyards have good flavors, and I think dry-farmed fruit generally tastes better.” He further explained: “As a winery, we look for old vine Zinfandels, preferably that are dry farmed. There is demand from winemakers for those grapes, because the vines are self-regulating and we know that the crop level will probably be in balance in relation to the growing season, and we don’t have to ask the grower to drop crop.”

Market niche for dry-farmed wines
Holdener believes there is a market for dry-farmed grapes, and growers should ask an above-average price. He labels and markets his wines as being from dry-farmed vineyards and encouraged others to do the same. “This is a marketing niche, and part of our target market is people who are more educated about Zinfandel, who look for wines from old vine Zinfandels and from historic vineyards and appellations,” Holdener said.

Dillian said his tasting room customers are often surprised when they learn he grows grapes without irrigation, and he is considering more marketing with the dry-farming concept. Runsten suggested dry-farmed wine producers participate in CAFF’s “Buy Fresh Buy Local” program that connects producers and consumers by publishing regional guides to local food products, provides marketing assistance and runs education campaigns to promote products.