If Sonoma County wine grape vineyards didn’t jump the starting gun this season, they wasted no time breaking out of the gate. That’s put pressure on growers to wrap up pruning much sooner than usual to stay ahead of breaking buds in Cabernet Sauvignon and other later varieties. Also, it increases the risk of frost damage to young, tender shoots – a threat that had already prompted some growers to take action to protect vines from frost several times by the second week of March.
Should the vines maintain this fast pace through the rest of the season, the 2015 crop is on track to an early harvest, says Karissa Kruse, president, Sonoma County Winegrowers. That would reduce the likelihood of disease damage to the crop from any fall rain. But, as it has the past several seasons, an early harvest could lead to an overlap in maturity of different grape varieties, creating more bottlenecks in the wineries.
An early end to harvest would also challenge the ability of growers to keep their employees busy until the start of pruning in late fall.
“A lot of growers are wondering if this is the new normal,” Kruse says.
As March entered its second week, growers were reporting bud break in Sonoma County had begun about a week ahead of last year’s early start and three weeks sooner than in more typical seasons, she notes. In the warmest areas, bud break in Chardonnay fields had advanced to about 90 percent or more, and between 80 percent and 90 percent in the Russian River and Dry Creek AVAs. At the same, about 25 percent to 30 percent of Chardonnay In some of the cooler AVA’s, including Alexander Valley, had reached bud break.
In some years, frost can remain a threat to Sonoma County vineyards as late as mid-May. “Although the days have been really warm, the nights have been cool,” Kruse says. “It could be a long frost season.”
However, several heavy rains in December and January replenished reservoirs used for frost protection. That, plus a number of new wind machines growers have installed in response to the continuing drought, should leave growers in good shape to fend off any frost this season, Kruse says.
With a few exceptions, growers and other property owners diverting water from the Russian River stream system for frost protection had to begin complying with the Russian River Frost Protection Regulation. This law requires that such diversions be done in accordance with a Water Demand Management Program (WDMP) approved by the State Water Board. It’s designed to manage the demand on the Russian River stream system during frost events to prevent fish from becoming stranded and dying from low stream flows.
River diversions represent only a relatively small number of growers, Kruse notes. Most Sonoma County wine grape growers get their water from reservoirs and wells.
“There’s been a lot of talk among growers about how to meet California’s new ground water management program,” Kruse says.
The goal of the Sustainable Groundwater Management Act of 2014, which became effective Jan. 1 of this year, is to reverse the long-term overdraft of aquifers in California. This law requires local groundwater sustainability agencies be set up by mid-2017. Those agencies with groundwater basins in critical overdraft must have plans in place to correct that condition by early 2020 and for groundwater pumping to reach sustainable levels by 2040. That includes most of the state’s groundwater basins and all of those in the Central Valley from Redding south to Bakersfield.
The other big water concern for Sonoma County growers involves the ongoing drought, Kruse notes. They are looking for answers to such questions as how to keep vines healthy with little rainfall? How much water in needed in the root zone? How do you irrigate during heat spikes?
“It seems like every conversation about vineyards involves the subject of water,” Kruse says. “But, as always, the growers are prepared for just about anything.”
Following three years in a row of record production, that includes the possibility of lower yields this year. “Quality, rather than tonnage, will continue to be the driver for Sonoma County’s wine grape crop,” Kruse says. “Growers will probably be dropping clusters to concentrate the fruit that’s on the vine. That would also put growers in a better position to get through the season if water supplies are short.”