Training vineyards to respect the California drought

May 20, 2014

Jason Lopez interviews Jean-Pierre Wolff on his vineyard in SLO County's Edna Valley.
Credit Jason Lopez

Not so long ago, the Paso Robles groundwater basin was thought to be practically limitless, at least by pro growth adherents. But times have changed, and this Central Coast wine growing region is now facing the most severe drought in recorded history. As might be expected, many are now looking for ways to protect the basin from further depletion, including a limit on further vineyard expansion.

Under California law anyone can drill and pump water under the land they own, even though the water is coming from the same supply across a vast area. Vineyards access the supply to irrigate their crops and expand their business, while residents tap the groundwater source for basic needs.

But as it turns out, grape vines are a drought tolerant plant and were historically grown in California without irrigation. Among the high-value, low-water crops on which to base an agricultural economy, wine grapes could fall near the top of the list.

Grow, Grow, Grow

Wine grapes are the top crop, in terms of value, in San Luis Obispo County worth $220 million in 2013 according to the county’s Agriculture Department. Grapes surged past strawberries, which were the most valuable the year before. The wine industry has changed the fortunes of communities on the Central Coast. So, expecting vineyards to stop growing in order to save water is a difficult proposition.

Sue Luft is the president of Pro Equity Water, a group in Paso Robles representing the interests of landowners, homeowners and some wineries. She has seen the well on her own property reach a point where it is close to drying up. “I guess if it runs out of water my home becomes a cabin, but wouldn’t be a practical place to live.”

Luft’s group has joined forces with Paso Robles Agricultural Alliance for Groundwater Solutions in a compromise that calls for a water district in Paso Robles. Dana Merrill, who’s a grape grower in Templeton, sits on the board of PRAAGS and believes the solution isn’t to stop the wine industry nor is it to send homeowners packing, who moved to area for the bucolic vineyard lifestyle.

“The solution is figuring this out for everyone. Maybe we don’t grow, grow, grow like we have, but there are a number of things we can do that we aren’t doing or that more of us need to do. People in Paso are can-do folks. We can keep the economy healthy and manage our water, too.”

Dry Farming

“Grape vines were originally grown in California without irrigation,” says Michael Costello, a professor of viticulture at California Polytechnic State University. “One of the confusing things is during a drought, farmers supplement what’s already in the ground from rain so the amount of irrigation might not be that much. But during a drought the vine still needs some.”

Wine grapes need as little as 19 inches of water each year. In a year of normal rainfall in California, vines that send their roots deep into the ground need essentially no additional water to produce fruit. This is the essence of dry farming. Its opposite might be described as conventional vineyard irrigation, which trains vine roots to stay closer to the surface. Fortunately, old vines can be taught new tricks.

Jean-Pierre Wolff of Wolff vineyards in Edna Valley, trained his 30 year-old Chardonnay plants, 16 years ago, to go deep for water. It worked. He doesn’t irrigate them. His Chardonnay grapes are considered ultra-premium and highly sought after by wineries.

“Yes, dry farming requires no irrigated water, but the soil needs to be recharged in order to make it work. That means we need to get some rain.”

Wolff is a bit of a maverick. He was born in Belgium and by his mid teens he wanted to be an agronomist. But he found himself studying nuclear engineering in college. In the mid 1990s, though, he felt the pull of his original idea: farming.

It was about 16 years ago he acquired his vineyard in Edna Valley.

“In Europe dry farming is the law in many areas. When you plant new vines you get three years of irrigating to get them going, but after that you can’t water. Dry farming was one of the first things I looked into.”

Wolff is reticent to say dry farming — and other techniques he uses to save water on his land — are magic bullets to solve the water issues of the Central Coast. But as a scientist he sets forth the idea that it’s necessary to keep an open mind and investigate a variety of solutions.

“I’m committed to taking care of the land. Keeping things in balance is very important.”

While we walked among his vineyards, Wolff shows several examples of pruning that also help to save water. At one vine he spreads the leaves and discovers a bird nest with baby chicks chirping loudly.

“Oops. We don’t need to bother them.” Wolff walks five more steps to demonstrate his point.