First signs of growth on Valley vines

Bud-Break is very early this year. Normally only the early varieties like Chardonnay and Pinot Noir show signs in March, but this year is totally different — even the late Red Varieties are emerging.

(Bud-Break, a term used to describe the tender young green shoots emerging from its bud, their protective cocoon.)

This can be one of the most crucial times for having a successful year or not in the vineyard. The young shoots are susceptible to major damage from the environment and animals. Most vineyards are protected from deer and rabbits by fencing which, monitored closely, is a successful deterrent for the creatures looking for a midnight snack.

The main concern is frost. Many people don’t realize how much damage can be caused in one cold night. It only takes around 20 minutes of freezing temperature to destroy the young tender shoots. This is why many vineyards have frost control. There are three ways to protect the vines from the overnight freezing temperatures Heaters, sprinklers and wind machines. Most heaters are not used due to environmental concerns and sprinklers are very expensive to install and maintain.

The Carneros, which is one of the coldest parts of the Valley with early varieties susceptible to frost, relies mostly on wind machines. Most wind machines are powered by propane; this is a reliable source of energy and is not affected by a power outage.

So how does the wind machine protect the vineyard? During most frost events the cold freezing air is heavier than the warmer air and settles close to the ground (around 40 to 50 feet). This is called an inversion layer. The wind machines are tall enough (30 feet with long blades) to mix the warmer air with the cold air around the fruiting zone. Most wind machines provide 1 to 3 degrees of warming for a 10-acre vineyard and are very successful in Sonoma Valley.

The great news is that the weather has been far from frosty, and  temperatures in the future forecast are safely warm as well.

David Cook operates Cook Vineyard Management. To learn more about the world of viticulture, call 707.490.8921 or visit Cvmgrapes.com. David also hosts the “In the Vine Country” radio show Tuesdays at 4 p.m. on FM 91.3.