California’s drought has become an integral part of the conversation around Wine Country. Nothing is immune from discussion, from how many toilet flushes are acceptable to the types of gardens and lawns that are best suited in an era with less available water.
As the area’s largest and most valuable crop, North Coast grape growers have been a popular point of focus as well as contention. In fact, an ongoing debate over the centuries-old practice of dry farming highlights the increasing pressure the industry faces as the state grapples with a new water reality that Gov. Jerry Brown said will take “unprecedented actions” to solve.
For some, the practice of dry farming — where natural rainfall, not irrigation, is used exclusively to produce a crop — is rooted in history. Yet, it is relevant to modern times as Napa wines that won the historic 1976 Paris tastings came from grapes that were dry farmed, though some of the chardonnay fruit was irrigated.
Proponents of dry farming note that drip irrigation can overly protect the vine from stress needed to produce top-quality wines, delay the development of full flavors until later in the growing season and result in wines with higher alcohol content.
“A bigger question is why people irrigate?” said John Williams, the owner of Frog’s Leap Winery in Napa, which has been dry farming its eight vineyards since opening 35 years ago.
For others, however, the practice is ideal, but not feasible to be widespread throughout the area’s diverse landscape, especially in areas where the soil is sandy and vineyard roots are not deep, such as hillsides. Not all soil is similar to that of Napa Valley, where Williams estimates about 20 percent of the vineyards dry farm.
“Shallow soil does not hold sufficient moisture to grow a vine,” said Rhonda Smith, the viticulture farm advisor for the UC Cooperative Extension in Sonoma County.
Additionally, research has shown that dry farming can reduce a crop yield significantly, bringing serious economic consequences.
“Dry farming is a question to look at closely,” said Laurence Sterling, operations manager for Iron Horse Ranch and Vineyards in Sebastopol. “It’s a question of where, what and how?”
Sterling argued the root system along Iron Horse’s 160 acres of vineyard around the Green Valley American Viticultural Area (AVA) would be too stressed relying solely on dry farming because of its soil makeup, a fine sandy loam soil called “Goldridge” where the roots don’t go down more than five feet. “Vine roots grow where there is water,” Sterling said. “The vine can’t be physically moved.”
So who’s right? Like many contentious topics, both sides have valid arguments. But growers and academics said they don’t expect a massive exodus to dry farming in the future. However, within the debate, there is a serious recognition that growers are moving toward using the smallest amount of water possible — and not a drop more — especially through new technologies such as soil moisture monitors and devices that gauge the vine’s water status. It may not be “dry farming,” but it’s tilting toward the idea that conserving water is better for quality, the environment and the long-term health of the vine.
“I see an increasing number of growers that are doing components (of water conservation),” Smith noted.