Chardonnay grapes on vine AndrewHagen/Thinkstock
Close-up of two bunches of ripe Chardonnay grapes on a vine, with vineyard background.

With weather on his side, Paso Robles grower is optimistic about 2017 crop prospects

“I can’t tell you just how happy all of us growers in this area have been to see that kind of rainfall. It was a well-needed godsend, especially after the El Nino weather predicted for last year didn’t materialize.”

In early June, about a month or so before his 2017 wine grape crop is expected to start coloring up, Central Coast grower Jason Yeager was pleased with what he’s been seeing in his vineyards this year. That includes plentiful winter rains and soil profiles brimming with moisture for the first time in several years.

He’s a fourth-generation member of a wine-grape growing family in Napa Valley, where he  managed a vineyard before moving south to Niner Wine Estates in 2011 to become director of vineyards. He looks after 212 acres of red and white wine grape varieties, including two vineyards near Paso Robles, Calif., and one, about 30 miles south, in the Edna Valley. The varieties include Albarino, Cabernet Sauvignon, Carmenere, Chardonnay, Grenache, Pinot Noir, Sangiovese, Sauvignon Blanc and Syrah.

Following five years of drought, each of the vineyards has received double the average amount of rain since last fall.

“I can’t tell you just how happy all of us growers in this area have been to see that kind of rainfall,” Yeager says. “It was a well-needed godsend, especially after the El Nino weather predicted for last year didn’t materialize.”

That’s on top of favorable spring weather that included none of the typical post-bud break frost events, no vine-stressing heat spikes and a promising bloom in late May.

Not surprisingly, he’s walking with an extra bounce or two in his steps these days.

“I’m pretty bullish on this season,” he says. “The fruit set is looking very good, particularly in the Chardonnay in the Edna Valley and Cabernet Sauvignon and Syrah in Paso Robles. And, the clusters are a bit larger than usual. I’m looking forward to some really high-quality fruit and a nice amount of crop.”

Depending on the particular wine program that he’s producing for, Yeager tries to limit yields in his Paso Robles vineyard to from 1-½ to 3 tons per acre and to 3 to 4 tons per acre in his Edna Valley vineyard.

In the previous two seasons, parched soils required unusual winter irrigation of his fields, he notes. This year, he may be able to hold off his first application of water until early July,

Not surprisingly, the high soil moisture levels this spring have stimulated vigorous growth of his vines.

“In our Paso Robles vineyards, we’re seeing more growth than in any of the past five or six years.” Yeager says “Even in the Paso Robles area, where soil moisture tends to be more limited the vineyards are looking very healthy”

In fact, this is the first season since the drought began that he’ll be hedging the vines. Also, he’ll probably do more canopy work than usual.”

This season hasn‘t been without a glitch or two, however. His Edna Valley Pinot Noir vines produced some sterile shoots sporadically throughout his blocks. It’s not uncommon for this variety, says Yeager, who describes as a “bit finicky.”

Although he’s seen sterile shoots in Pinot Noir in the Carneros area of Napa Valley, this is the first time he’s seen it in his San Luis Obispo County vineyards. He plans to deal with it by thinning fewer clusters than usual in the affected blocks to meet his fruit yield target.

Some cool weather and rain during bloom caused a little shatter in the Cabernet Franc, Cabernet Sauvignon, Grenache and Merlot in his Paso Robles vineyards.  However, the larger clusters should compensate for any production lost to the shatter, Yeager notes. And, by providing a little more space between berries, the shatter could even enhance fruit quality by improving air circulation and sunlight penetration within the clusters.

Like some other area growers, Yeager encountered a new fungal disease for the first time this season – downy mildew. That was after some unusually wet spring weather was followed by warm temperatures. In his case, the disease developed in several blocks in his Paso Robles vineyards and one block in the Edna Valley. Prompt treatment with a fungicide limited any infection to just the lower leaves.

“The leaves got all spotty, but we didn’t see any necrosis in any of the blocks,” Yeager says. “Downy mildew attacks all the green tissue on the vine – the leaves, the canes and the fruit. If you don’t get on top of it right away, the disease can turn ugly pretty fast.” 

Yeager was attracted to the Paso Robles area because of the potential he saw for the region to distinguish itself in the world of wine grapes.

“The growing conditions in the Paso Robles region are unique,” he says. “The quality of the fruit now being produced here is tremendous. The growers and winemakers are teaming up to create some excellent wines that soon could rival the best in California.”

Meanwhile, Yeager has had to adjust some of his North Coast thinking to fit the much different soils and microclimates here. One was to modify his approach to canopy management.

“At the Napa Valley vineyard it wasn’t uncommon to make multiple passes down the rows removing laterals and leaves,” he says.  “Here, in Paso Robles, there have been years when I didn’t touch the canopies in any of the blocks. It’s almost as if the vines here regulate the amount of foliage they need by themselves. You have to be really careful to limit exposure of the clusters to sunlight and protect them from sunburn.”

Because of limited supplies of ground water throughout the Paso Robles basin, he drip irrigates using no more water than needed to support the vines. Yeager figures he’s growing grapes using as little as one-fifth the amount of water he used for drip irrigating in Napa Valley.

Yeager has installed two drip emitters per vine, one on either side and each on separate lines, in all of his blocks to allow for partial root zone drying. This way, he can alternately apply water to one side on the other from one irrigation to the next.

“It’s starting to becoming a fairly common practice, here,” he says, “The idea is to force the roots to go deeper for water.”

His double-poly irrigation system also lets Yeager direct water only to areas of a block that need it. With this system, which features two separate drip hoses in the same row, he can use one hose to irrigate the whole block and the other to irrigate only areas of the block that undergo more stress than the rest of the block.

With an eye on climate change, future re-plantings will use root stocks that are more tolerant to drought.

“We’re trying to get to where we can dry-farm the vineyards,” he says. “We’ll lose some yield, but we’ll also improve quality of the fruit by producing more intense phenolics and flavors.”

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