For organic grapes, the soil is “full of life”

By Kevin Hecteman

For Ivo Jeramaz, it all starts with the ground. No dirt. Ground.

“Dirt is a derogatory word for soil,” said Jeramaz, vice president of vineyards and production at Grgich Hills Estate in Rutherford. “Dirt is devoid of life. The ground is full of life.”

Jeramaz – whose uncle, Miljenko “Mike” Grgich, is responsible for the chardonnay that beat French wines in a tasting competition in Paris in 1976 – converted his family’s vineyards from conventional to organic production. about 20 years ago. His goal begins with building what he calls “disease-fighting soil”.

This includes the use of cover crops and composting, and the absence of plowing. He says it’s because tillage adds oxygen to the soil, causing the microbial population to explode and then the organic matter responsible for the soil structure to be consumed. “You get the first year of fertility,” Jeramaz said. But afterwards, everything is downhill.

“Microbes are key ingredients for soil success,” Jeramaz said. “It’s not that we made it up, that’s how nature intended it.”

Organic growers like the Jeramaz family have combined to produce 3,777 acres of organic wine grapes harvested in Napa County in 2019, according to the 2019 California Department of Food and Agriculture Organic Crop Report. Only Mendocino County, with 3,993 acres, harvested more organic vineyard area.

For comparison, winegrowers in Napa County had 43,365 acres of production in 2019, while Mendocino County was home to 16,506 acres of production, according to the counties’ 2019 harvest reports.

Joseph Brinkley, who grows organic wine grapes near Hopland, said going organic requires a change in mindset.

“On the organic and biodynamic side, it’s really like trying to create a healthy system and organism,” Brinkley said. “You are really trying to prevent any problems, and preventing these problems often means cultivating in a more balanced way so that you don’t run out or excess, for example, of a nutrient, water or light.”

To control late blight, an organic wine grower needs to “make sure your canopy management is planned properly,” Brinkley said. “You have a good flow of air and light through the canopy, protecting the fruit.”

Like Jeramaz, Brinkley focuses on soil health, starting with soil testing to check the pH balance. Brinkley said any compost added to the soil would benefit organic matter and biological activity. He also used fish emulsions and soy and seaweed products with nitrogen. Then there is the manure of the sheep that graze in the vines.

“Maybe 20, 30 years ago – or even 15 years ago – there weren’t a lot of organic fertilizers on the market,” Brinkley said. “Over the last 10 or 15 years, the market has certainly shifted to organic products in this way. Consumers want it, it seems, and there seems to be a growing awareness and need or demand.

Controlling the pressures of diseases and pests involves a very different approach.

“We just don’t have the vast toolbox of standard chemicals like conventional growers do,” said Martha Barra, who operates a farm in Redwood Valley.

Barra said she was using a biologically approved material containing chrysanthemum oil to control leafhoppers and stiletto oil for late blight.

“We’re really limited to what we can use, but it seems to be working for us,” Barra said. “We have our vineyards in balance. It has to do with the timing of application. We know how the cycles go, like with leafhoppers or mites.”

Jeramaz said he discovered that conventional materials “get into the sap of plants and influence everything, and weaken the immunity of plants. Although you can kill late blight for a few years, you weaken the plant.” This, in turn, shortens the life expectancy of the vine, he added.

“A generation ago the vines lasted at least 40 to 50 years,” Jeramaz said. “Today, with all this new technology, we only have half of it. It’s extremely expensive.”

The oldest Jeramaz vineyard in Calistoga contains 120-year-old Zinfandel vines; some of his cabernet sauvignon vines in Yountville were planted in 1959.

Brinkley’s thinking about life expectancy aligns with Jeramaz’s.

“I feel like you’re getting increased longevity from this planted field,” Brinkley said. “Instead of maybe 20 to 25 year replantings, we are looking at 35 to 40 years, or maybe even longer.”

Brinkley said the difference between conventionally grown and organically grown grapes will largely depend on the grape variety and the location of the vineyard.

“Often times you will find reduced yields in the organic system compared to the conventional system,” said Brinkley, “but with these reduced yields you will often find a greater concentration, especially in the reds – some of the phenolics, the color profiles. “

Jeramaz finds that in his neighborhood, sugar buildup, measured in brix, can happen quickly.

“Phenol, which we all need for good wine, is sometimes two weeks late,” Jeramaz said. This leads the winegrower to think that the grapes are not yet ripe.

“By the time they’re happy with the tannins in the skins, we’re talking about 28 brix,” Jeramaz said. “It’s 70% alcohol. Nobody wants 70% alcohol.” Increasing the number of grapes on the vine helps, he noted.

“We would like to slow the build-up of sugar in plants,” Jeramaz said. “By putting in a little more grapes, that’s what happens. Not only have we doubled our output, but we have better quality than ever.

Organic winemakers share a big problem with their conventional cousins: California’s severe drought.

“It’s pretty brutal,” Brinkley said. “The north coast, in particular, we have certainly seen serious reductions in water use.”

Brinkley said the organic status of his vineyards could help them weather the dry years.

“Because of the years of cover crops and composting, we’re really trying to increase and grow organic matter in the soil and allow the soil to be that bank, or that reservoir, that we’re constantly adding to,” did he declare. . “The vines are more resistant to these extreme pressures because we have invested in them through compost and cover crops, root mass and soil biology.

Barra said she had already reduced the wineries’ harvest estimate by 30% at the start, and “as we deliver we lose another 20%,” she added.

“It’s happening across the board,” Barra said. “The tonnage just isn’t there.” She said her vineyard foreman said “the rain just doesn’t come down to the roots and lower nutrition.”

Conventional farmers who plan to make the switch are in a long-term commitment: the vineyard must wait at least three years after the last application of any banned material before it can be certified. Brinkley said the biggest hurdle “is getting alignment from the top, from the executive leadership, at all levels and on the pitch.”

(Kevin Hecteman is associate editor of Ag Alert. He can be contacted at [email protected].)

Permission for use is granted, however, credit should be given to the California Farm Bureau Federation when reprinting this article.