Last night the temperature in Napa dipped to 34 degrees. It’s not uncommon for wineries, grower relation reps, PCAs to visit 1605 Los Carneros Avenue and once they’ve taken a look at the vineyard inquire about frost protection. The Farmer often looks out over the acreage, turns back towards them and says, “That’s what we call on a wing and a prayer frost protection, Son.” The Farmer isn’t much of a praying man, he’s more of a shot of tequila and hope for the best man.
Since the first vines were planted in the late 1960s The Farmer never had frost damage…that was until 2008. The lay of the land, wind off the San Pablo Bay, the water table which extends from Carneros Creek and runs along Block 8 of Chardonnay maintains moisture in the air and constant circulation of that air; two welcome elements when combating frost. Old Farmer wisdom and an additional trick up his sleeve rounds out the wing and a prayer frost prevention plan – The Farmer puts a bow in the cane when pruning and tying that lifts the buds about six more inches off the trellis wire, buying him one final bit of frost insurance. In 2008, two things occurred which significantly affected the Thomson Vineyards crop that year and going forward; both experiences have left The Farmer a bit more anxious than usual: 1) Unseasonably late frost and 2) The Farmer’s discovery that the lay of the land had been altered significantly enough by neighbors to prevent circulation of air from occurring through one subsection of the vineyard.
Moral of the Story: Love your neighbors and realize that no matter how much time you spend in church sometimes mother nature is more powerful than the “powers that be”.
The Industry Issues Committee of the Napa Valley Grapegrowers prepared the following frost protection guidelines and highlights some of the important aspects of protecting The Farmers valuable crop.
1.Whenever possible, communicate with your neighbors about frost season: its implications, practices, and duration.
2.Know your site! Start-up times for all machines & methods may vary according to your own unique sites. Employ weather stations, frost alerts, or other methods of keeping you abreast of the current situation in your vineyard.
3.There are many passive frost control measures you can employ, including delayed final pruning and different floor management strategies, i.e. mowing and where permitted, discing. Investigate all of your options.
4.Calibrate thermometers in a 32 degree Fahrenheit ice bath.
5.Monitor the ambient temperature and turn on the frost system only when needed to minimize energy needs (gas, diesel, and propane) and water use.
6.Timing is important. If the temperature is hovering above 34 degrees at day break; the chance of a frost are minimal. If temperatures are plummeting early in the night, then the threat of frost could be great.
7.Wind machines should be full throttled at 34 degrees Fahrenheit, as dew point can play a huge role in vine-perceived temperature.
8.For sprinkler operation, first and foremost: consult your dew point chart. In very general terms, sprinklers should be started by 34 degrees, particularly if it is before 5:00 a.m. and the dew point is below 30 degrees Fahrenheit. If ice forms on the vine/trellis, then the sprinkler system should not be turned off until all ice has been melted, regardless of the ambient temperature.
9.Try to put yourself in the neighbors’ position when it comes to noise generated by wind machines. Protecting against frost is within everyone’s right to farm, but we should also strive to be good neighbors.
10.Monitor the operation hours of machines. Temperatures should be monitored once frost systems are running. If a cloud layer begins to form; chances are the temperature will rise above 32 degrees and further frost protection may become unnecessary.
One of The Farmer’s favorite days of the year is April 15. Not because he gets to visit his tax accountant, but because once he’s passed that milestone the chances of frost damage significantly decrease and he can take a breather, relax a little and tip back a few margaritas. Be sure to look for him at Compadres on Tax Day. Or JV Wine & Spirits, his new favorite Friday hangout. This post has me looking for 80s hair band revival concert tickets. With any luck I’ll be at a Bon Jovi concert with my tax refund! Priorities.