It was a nail-biter but we are happy to report that the recent spring freeze passed us by.
The local forecast called for possible freezing temperatures on Wednesday morning. Our vines had been pushing rapidly and had shoot lengths varying from 8 inches to 36 inches. The Italian varieties were leading the charge (Sangiovese, Malvasia Bianca, and Vermentino) with the Syrah neck and neck, which is what we expect on our site. There were numerous flower clusters on all varieties just waiting to bloom and become fruit clusters so we were of course concerned about freeze/frost damage.
In anticipation of a possible spring freeze David has been installing frost protection sprinklers. They are designed to apply a specific droplet size at a specific rate to prevent the plant tissue from freezing. Although it sounds counterintuitive, the concept is that the water coats the plant tissue and as it freezes it produces a small amount of heat (an exothermic reaction) which raises the temperature around the plant tissue and prevents it from freezing. We have the sprinklers working in zones 5, 6, and 7 and tested them on Tuesday in preparation for Wednesday morning’s possible freeze. Typically at our site the coldest temperatures occur just before sunrise (around 7 am) but the sprinklers need to be engaged before freezing temperatures occur. Our plan was to set the alarm clock for 5 am to check the temperature and dew point and start the sprinklers if it looked like they could drop to harmful levels. When we arose the temperature was 34.8°F and the Dew Point was 32° and both were on a downward trend. With several hours of potential temperature drop we decided to turn on the sprinklers. We ran them until 7:30 am when the temperature had increased to 38°F and was on an upward trend. So we were confident that we wouldn’t see any frost/freeze damage in Zones 5-7 (Malbec, Vermentino, original Cabernet Franc). According to our weather station our lowest recorded temperature was 33.7°F and the lowest Dew Point was 31.0° F and we have not seen any frost damage in any of the blocks. Whew, one step closer to harvest!
