California’s recent rainfalls have been catastrophic for many. But some wine industry experts say there may be an unexpected silver lining: Heavy rains seem to have not only recharged drought-thirsty aquifers and water tables, but also flushed away, or leached, toxic vineyard salt deposits.
This is no small thing. Salts in soil contain important micronutrients, but some—like sodium, chloride and boron—carry a toxic punch if left to accumulate, a problem exacerbated by California’s recent droughts. It’s a spot of good news in an otherwise dreary California news cycle.
Growing Condition Impacts
Without leaching, toxic salt deposits infiltrate vines and their root systems. This directly impacts growing conditions and vineyard productivity. “Our harvest 2022 was off by between 20% to 30%,” says Jeff Newton, president and CEO of Coastal Vineyard Care Associates. The organization farms about 4,000 acres throughout Santa Barbara County. “One of the main reasons is that we just haven’t had the leaching that we’ve needed over the last several years.”
Salt-poisoned plants dehydrate, desiccate and even die. Leaves “burn,” or turn brown. Grape quality also suffers. “We have been in a very real drought these past few years, and with that, you get an accumulation of salt in the soils, which can impact the quality of the grapes,” says winemaker Ryan Prichard of Sonoma’s Three Sticks Wines. “These heavy rains help flush these salts out, and renew some of the life force in the soils.”
Not a Drop to Drink
Ironically, surface salt build-up can also contaminate ground and well water, resulting in salty irrigation water. “As our wells have been drawn down due to drought, we do end up irrigating with less quality water,” says Craig Ledbetter, vice president and partner at Vino Farms in Lodi. “Salt intrusion on the west side of Lodi is highly possible due to its location to the Delta, and its influence on ground water.”
Naturally salty irrigation systems play a part, too. Josh Beckett, the managing partner and director of operations for Peachy Canyon Winery on California’s Central Coast, oversees five estate vineyards sprawled throughout western Paso Robles. “The irrigated vineyard water is naturally salty,” he says. “When you’re only irrigating enough just to benefit the plant itself, salt tends to build up. These big rains are flushing out those salts, cleaning up the soils.”
Salt of the Earth
Arid regions tend to build up greater salty soil deposits. “Most regions that have salt problems in the soil are arid regions, which typically don’t get very much rain,” says Mark Greenspan, president, owner and viticulturist at Advanced Viticulture in Windsor, Calif. “So in Paso Robles, where I’m most familiar with significant, severe salt issues, their annual rainfall is usually eight to 10 inches.”
Brackish Central Valley’s Lodi and Delta regions also suffer from salt deposits. “During droughts, salts become a problem—more so in the Delta versus Lodi,” adds Ledbetter. “We definitely have salt (boron) build in the ground, because we have not had the rain to flush the soil in the Delta. I have not seen much of that in Lodi.”
Additionally, certain soil series hold salty deposits, such as Santa Barbara. “The underlying geology, soils, rocks—they’re all sedimentary and formed under the ocean, so salt is in the original geology,” says Newton.
Location, Location, Location
Further north, salt deposits remain an exception, not the norm. “North Coast, we get a lot of rainfall, we don’t have salinity problems, except for isolated areas in Carneros, where it’s close to San Pablo Bay, and there some saltwater intrusion problems,” says Greenspan.
“If you look at Southern California and Santa Barbara-area soils, they don’t have the rainfall, the growth, and the soil development that we do here in the north,” says Stu Smith, veteran wine grower/owner of Smith-Madrone on Napa Valley’s Spring Mountain. ”And so our soils are able to absorb most of this rain with little impact.”
“It’s interesting to me,” observes Newton. “Because in Napa, for instance, we know growers who, when you talk to them about the salt issue, their eyes glaze over—because they have so much rainfall, so salts are leached. They may have a lower salt load for their own geology, too. But in Santa Barbara County, for the nearly 40 years that I’ve been farming here, we’ve always been concerned about salts.”
The recent floods may have washed away salty vineyard soil deposits, but they left behind a residue of uncertainty. Climate change’s troika of fires, droughts and floods leave wine growers tap-dancing rapidly each harvest.
Moreover, flood soils prevent vine tenders from pruning and spraying for spore and vines disease mitigation. Wetter, warmer soils also threaten early bud break, resulting in possible spring frost damage, uneven ripening or higher yields.
And yet, most wine growers prefer to look on the positive side of California’s recent floods. “With all this rain, it almost looks like Ireland around Paso now,” concludes Beckett, a Paso native. “I haven’t seen rain like this since I was a kid. It’s exciting.”
Last Updated: June 5, 2023