The drought that has gripped California for the past three years has finally taken a toll on the state’s winemakers. In the past, the state’s massive agriculture industry has had no problem turning out enough wine grapes for its producers. But as the drought has worsened, even more water has been needed for farming, and that has cut into the amount of water available for vineyards. (This year, the grape harvest is expected to break records, but even so, it will use less water than in past years.) In response, winemakers are turning to more expensive methods of irrigation, as well as trying to grow more drought-resistant varieties of grapes.
On the 21st. In April, Governor Gavin Newsom declared a regional drought emergency in Sonoma and Mendocino counties. After a winter of extremely low precipitation, the region’s main sources of irrigation water – Lake Mendocino and Lake Sonoma – are depleted.
Drought is unfortunately nothing new for local gardeners. Many of them continue to adapt their winemaking practices to the ever-changing climate.
After a glass fire in 2020, Cornell Vineyards winemaker and winemaker Elizabeth Tagni has spent the past eight months restoring the mountain plot in Sonoma Valley’s Fountaingrove AVA. Due to varying degrees of heat damage, 11 of the 20 blocks on the property will be replanted.
Now Tagni must find ways to make the vineyard more drought-resistant. New plantings will have wider spacing between rows to provide wider cross strips (up to 20 inches at the top), which will promote shade. She carefully selected drought-tolerant rhizomes (1103 Paulsen and 140R) that can establish a deeper root system more quickly and decided to plant a new variety, Carmener. This late ripening grape with thick skin prefers warm, sunny locations.
All of these decisions took into account factors such as exposure, soil type and soil depth, Tagney says.
The property is southwest oriented, which increases sun exposure and heat absorption. The soil consists entirely of sandstone with minimal water holding capacity; a depth of only 12 inches limits root growth. These factors, combined with climate change, have led me to make some decisions to manage the area differently, she says.
Lake Sonoma after a winter of extremely low precipitation / Photo: Jak Wonderly
John Hamel, general manager of viticulture at Hamel Family Wines, has radically changed his growing style to adapt to the climate. In 2017, he slowly began transitioning his four vineyards in the Sonoma Valley and Moon Mountain AVA to dry farming, which he defines as zero irrigation during the growing season.
I began questioning our irrigation practices after returning from a trip to France, where a prominent winemaker said irrigation disconnects the plant from its terroir, Hamel says. Our winery has begun to try non-irrigated cultivation and has found excellent expression in the wines.
According to Hamel, dry-grown grapes are more powerful and have more complex tannins. We’ve seen it in both the fruit and the resulting wine, he says.
Hamel explains that in order for cultivation on dry land to be successful, the vine’s roots must germinate deeply to withstand the drought.
It is generally agreed that old vines make better wines….. The main reason is that the roots are deeper and have fully colonized the soil profile, he says. Vines that are not irrigated must root deeply and use water efficiently.
Hamel says vineyards grown on dry farms are more resilient to climate change and more resistant to natural droughts because of their deeper roots.
The transition to agriculture on dry land is not without problems. We first determined how far we could grow the vines without water to improve the quality of the fruit, Hamel says. We want this practice to raise quality, not lower it.
Unfortunately, droughts are nothing new to gardeners in Sonoma and Mendocino. / Photo by Jak Wonderly
The second problem, he says, is one that many modern farmers face today: Most vineyards were previously over-irrigated, which contributed to shallow rooting and a physiological infrastructure that relies heavily on regular irrigation to stimulate the growth cycle.
In addition to dry cultivation, Hamel also uses other viticultural methods to promote an earlier growth cycle of the grapes. If pruned earlier, plants will start budding as soon as environmental conditions allow, he said, although this increases the risk of bud damage in spring frosts, he warned.
With at least a few days off during the growing season, Hamel thinks he can harvest earlier. This is important because during periods of higher temperatures, usually in August and September, it is more difficult to produce quality crops under drought conditions. These events are becoming more frequent and more extreme, he says.
Although dry farming is not a solution for all growers, Hamel says there is such a thing as over-irrigation. This means that the plant gets water that it does not necessarily need, depending on the calendar.
It’s better to make decisions based on data, he said. Vintners must rely on measurements of soil moisture and crop water status to make irrigation decisions. Too many irrigation decisions are made without real data.