Sonoma County got an early start on harvest Wednesday night as work crews picked grapes by hand at J Vineyards & Winery’s property in the Russian River Valley.

The start to this year’s harvest is one of the earliest on record for Sonoma County, according to the Sonoma County Winegrowers organization, which noted moderate temperatures have aided a crop that is expected to be of high quality but less bountiful than 2013’s record-breaking yield.

“It went great. The yields were a little below what we were expecting,” said Scott Zapotocky, director of vineyard operations for J Vineyards & Winery. The crews picked 8 tons of pinot meunier that will be used for J Vineyard’s sparkling wine.

Workers were slated to be out again Thursday night on the J Vineyards property. Winemakers prefer that grapes for sparkling wine be cold when crushed, and thus want picking to be conducted during the night or early morning.

“The quality itself looked really good. When we were tasting the juice off the press pan, it had a really nice concentration,” Zapotocky said.

Sonoma County’s first harvest was a little later than Napa’s, which kicked off early Wednesday morning over at the Game Farm vineyard between Yountville and Oakville.

Local growers this season remain concerned over drought conditions even though late-winter downpours provided key moisture to the vineyards, said Karissa Kruse, president of Sonoma County Winegrowers. Some Alexander Valley vineyards have been especially affected because of curtailment of their water rights to the Russian River.

Those affected wineries, located north of Healdsburg, have been able to maintain their crops by either trucking in water or using reclaimed water from the city of Healdsburg’s water treatment plant, Kruse said.

The technology that growers use has also improved their water efficiency, she added.

In the past, they may have watered according to a set weekly schedule, but now they can target specific water use for each vine row by measuring soil moisture and the water stress in grapevines.

“We are no longer guessing what the vines really need,” Kruse said.

J Vineyards & Winery uses a drip irrigation system that emits a half-gallon of water per hour on its vine, allowing Zapotocky to tailor water use specifically to its needs.

“We use a burst of water when they need it, when it’s hot,” he said. “But you also do not want to do too much.”

Despite escaping severe problems so far from the drought, growers will be hoping for rains during late fall after harvest to help replenish vines before winter comes, Kruse said.

“It’s really a concern of what happens moving forward,” she said. “Right after harvest, we typically do get rains. Those rains are pretty critical.”

You can reach Staff Writer Bill Swindell at 521-5223 or bill.swindell@pressdemocrat.com. On Twitter @BillSwindell.