Is it Spring Yet? Idaho’s Grapevines Want to Know
Much of Idaho has had a long, cold winter. In Idaho’s Treasure Valley—home to the Snake River AVA and the Eagle Foothills AVA, March has come and gone like a lion. It will go down for now in the history books as the snowiest on record in over 70 years, getting just over nine inches.
Three hundred miles north in Idaho’s Lewis and Clark Valley AVA, winter has been, if not exactly a lamb, at least not as temperamental as the king of the beasts. With a low elevation of 725 feet above sea level at the inland port of Lewiston, Idaho, this part of Idaho is sometimes referred to as the Banana Belt of the state. Differences in climate and geography can mean big variations for the growth cycle of Idaho’s grapes, including when budbreak happens.
Budbreak: First step for Idaho Grapes
In Idaho, budbreak typically happens in April. Budbreak means that tiny buds that rest between the vine and the leaf stems start to swell. Eventually shoots begin to grow from the buds. The shoots will sprout tiny leaves which begin the process of photosynthesis, and, about 40–80 days after budbreak—often around Mother’s Day— the vines begin to flower. Each individual flower will become a small, hard, green grape which will be transformed over the summer as the grape fills with water and sunlight catalyzes sugar and flavor accumulation.
The climate and geographical differences between and within Idaho’s AVAs can have a big impact on when budbreak happens in Idaho.
Variations on Springtime
Just outside Lewiston, Coco and Karl Umiker of Clearwater Canyon Cellars are spending the first week of April bottling their 2022 vintage white and rosé wines. Karl says budbreak for their seven acres of vines is still about two to two and a half weeks away.
“We’ve just started to see the beginning of sap flow in the vines,” he said. “Budbreak will happen right after that.”
Sap flowing means the vines are waking up from their winter dormancy. Sap will flow to those areas where the vine has been pruned. Once temperatures reach a consistent 55 degrees, budbreak occurs.
Karl noted that a late budbreak is not necessarily a bad thing. In 2022, a delay to budbreak of about three weeks resulted in a delayed harvest, which can sometimes pose a risk of early frost before the grapes can be harvested. On the other hand, an early budbreak can also leave the grapes vulnerable to a late frost.
“Two days ago, we had a good ground frost,” he said. “I was glad the vines weren’t active yet.”
The Umikers own a vineyard on land that has been passed down through generations of their family for over one hundred years. The land overlooks the Clearwater River near its confluence with the Snake River and is located about 1,400 feet above sea level, giving them cooler weather than some other Lewis and Clark AVA vineyards which reside closer to the valley floor.
Karl, a soil expert, notes that soil temperatures also effect how quickly spring comes to a vineyard. At their higher elevation, Clearwater Canyon has a silt loam soil that stays cooler, holds water longer, and dries out more slowly—which keeps the vines from waking up as quickly. Down in the Lewiston valley, soils with more sand content drain faster and heat up more quickly, which plays a role in earlier vine activity. In short, spring can arrive in roughly the same location at varying speeds.
Not Waiting on the Weather
As they wait for spring, the Umikers are staying busy.
Earlier this winter, they finished pruning their vines and mowing a cover crop of native plants, returning all as mulch into the soil. Soon they will bottle their 2021 vintage of red wines, almost every bottle of which is already sold to members of their wine club or to local retail establishments.
This year marks the twentieth anniversary of their vineyard and 19 years of making wine. The Umikers say they’ve learned to adapt continuously to whatever the weather does and to the demands of a growing family business. They’re not too concerned if budbreak arrives a few weeks later this year in Idaho’s northernmost AVA where Idaho’s winemaking prowess dates back to the 1860s.
Referring to the recent frost that hit while their vines were still dormant, Karl suggested the vines knew it was too early to be waking up just yet.
“It seems like the vines know exactly what to do,” he said.
“The wonderful thing about grape growing,” Coco said, “everything has a season. We follow along with Mother Nature and walk alongside her.”
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