Spring Frost Alert?

April 1, 2010

Vineyard wind machines

And then, a far scarier thought enters our minds…..with bud break comes the threat of Spring Frost!!

If the temperature drops too low after bud break, then all that new, fragile, green growth can be permanently damaged leading to lowered grape production and the loss of way more potential wine than is healthy to think about.

In Napa, devastating spring frost is relatively rare, but in 2008, just such a thing occurred. Many vineyards and wineries lost up to 75% of their crops! ….and others lost entire vineyards worth of potential grapes….

There are several contingency plans in place to help avoid the frost damage. One of these is the use of large wind machines that move a naturally occurring layer of warm air called an inversion layer. This inversion layer stays within the same general area above the ground so when it gets cold, the fans are turned on and this warmer layer of air is blown down to help protect the vines.

Of course this means vineyard managers are waking up at 3am because a frost alarm sounded so they can turn the fans on but the loss of sleep is worth it to protect the precious vineyard (of course I say this cause I am comfortable in my warm bed at these wee hours of the morning). With these giant fans activated throughout the valley, it sounds similar to a small armada of helicopters flying through the vineyards…..thoooom thooom thooom…..are we under attack?! No, it is just cold outside…

Old style wind machine with smudge pots

Another protective measurement taken is the use of smudge pots which has in recent years become illegal due to the pollution caused. The smudge pots use smoke to keep the vines warm.

Sprinkler systems can also be used to keep the vines warm and the new growth safe, though if not handled properly can cause more damage then they prevent.

Some interesting new techniques are being tried such as coating the vines in ice. This may seem counter-intuitive, but like how an igloo made of ice keeps Inuit warm, a layer of ice can actually keep the vines warm enough to survive frosty weather. Interesting stuff, I know.

Sprinklers mounted in vineyard

So this week I am checking our vineyards for bud break and leaf growth and of course, to see if any have sustained frost damage.  As of now the temperatures in Napa have been cooperating, but it’s never too early to start monitoring what will become the 2010 Tom Eddy wines.                   Posted by Jason

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