I'm a fan.

I love this portable wind machine that showed up in the Opus One vineyard last week; the fan one day, the propane tank the next.  The vast majority of vineyards around the Napa Valley have been pruned now and vineyard-vistas are greening up as leaves and shoots (white varietals) are appearing atop vines as a fuzzy, pale green haze.

The Opus One vineyard is, of course, Cabernet sauvignon - an expensive crop that needs to be protected from frost.  With the possible threat of frosty spring mornings just around the corner, vineyard managers up and down the valley are making sure that frost protection means are in place, and in working order. Vineyard managers that employ overhead sprinklers for frost protection have been checking that their sprinkler systems will indeed sprinkle when called upon to do so, (as evidenced by the number of vineyards that have been getting a good sprinkler-dousing the past couple of weeks).

I finished pruning the Syrah today, making my spur and cane selections that is, I haven't tied them all down yet.  The Syrah vines are very enthused which makes tying the canes down difficult.  It also means that those little buds will be susceptible to frost damage if we have a chilly morning.  My fingers are crossed because I don't have a portable wind machine.

On another note, this past Wednesday's Napa Valley Register reported that more than 400 concerned citizens had showed up at a joint meeting of the Napa City Board of Supervisors and the Napa County Planning Commission (on Tuesday 10th March).  What are they concerned about? Vintners, growers and average folk are concerned about the unfettered growth of wineries within the agricultural preserve, wineries that "are becoming glitzy event centers that overshadow agriculture, generate too much traffic and use too much groundwater."  A group of  growers and vintners, notably Andy Beckstoffer and Dennis Groth, submitted a joint letter (which I'm sure got a frosty reception from the supervisors), asking the county to enforce regulations set in place under the 1990 Winery Definition Ordinance.  Problem is, the county repeatedly grants variances to new wineries to get around the laws the county itself instituted to protect the agricultural preserve. It's a highly contentious issue and I'm sure that a huge flap is fermenting.  Stay tuned.

Sprinkle liberally.

The record low temperatures that were forecast for last week did not materialise. Last night it was supposed to only get down to 36 degrees and it got down to 32 instead...weathermen!!!
I took this picture several weeks ago, around the time I did my smudge pot post. I imagined that Napa was going to be in for a frosty April but no, it has just been cool and damp all month long. Of course, the scarcity of freezing overnight temperatures has been great for the vines, thank goodness.
Besides fans, the other primary method of frost protection in Napa vineyards is the utilisation of overhead sprinkler systems, designed to apply .11 inches of water per hour. Overhead sprinklers require upwards of 50 gallons of water per minute per acre: at this rate full protection of the vineyard to temperatures down into the mid-20s can be achieved. These systems derive their effectiveness from the latent heat of fusion which is given up as the water turns to ice on the vine. The mixture of ice and water maintains the bud at 32 degrees, just one critical degree above the point where bud damage begins. The sprinklers then continue until well after sunrise and subsequently the ice melts. This is a rather expensive method of frost protection and an adequate source of water is essential. Sprinklers are however very quiet unlike the wind fans, and very clean unlike the smudge pots. The sprinklers can also be used at other times in the growing season for irrigation, heat suppression, and pest management. This year I am sure the sprinklers will be employed in the certain pesticide-death of the European Grapevine Moth.
Sprinkle liberally with water, add a dash of physics and you have the recipe for a successful harvest in the autumn.