May 03, 2012
Posted by Jason Saling, Vineyard Manager
Frost season doesn’t “officially” end until May 15th, although it is not so uncommon to frost well into June around here. In keeping with our commitment to environmental stewardship, our frost protection system is designed to use limited water resources.
We use what are referred to as Micro-Sprinklers. Similar to the type of sprinklers you see in a garden, they each have a small bladder inside that pulsates and emits small blasts of water laterally down the vine rows. Each one uses ~3 gallons per hour, and per acre we use ~15 gallons per minute. Other methods use approximately four times as much water.
Freezing water around the buds and leaves of grapevines protects them from freeze damage because of the heat generated in the freezing process. While small, it is enough to get trapped between the green tissue and the ice and keep the vines protected as long as it doesn’t get too cold (below 28 °F/-2.2 °C on average) or stay cold for too long (more than a few hours).
Also, we only really need to frost protect the lowest portions of our vineyards, because, like water, cold air flows downward. So on cool or cold still nights, cold air flows down from the hillsides and settles at the lowest points in the terrain.
Getting a frost call means waking up, coming to the vineyard and turning on the system. After years of working in the vineyards during frost season, I can safely say that there is nothing quite like seeing that sun come up over the horizon (which is also the coldest time of the morning), but at least, when it does, you know the coffee shop is open and the warming has begun.