Sweater Tree

We had some relatively cold weather here on the central coast of California this weekend. There was even some talk of snow down in Santa Cruz, but I think that fantasy melted by Saturday afternoon.

Not everybody in the area was hoping for flurries. Some growers in the Salinas Valley, the Salad Bowl of the World and the site of my current newspaper internship, were worried about this weekend’s weather. In talking to a few people about how lettuce, artichoke and strawberry growers were preparing for this weekend, I heard about a counter-intuitive frost-preventing trick used by farmers: misting plants with water during freezing temperatures to form a protective layer of ice.

This method of crop protection requires a slow, continuous misting of plants, otherwise growers risk even greater damage to their crops than if they had done nothing at all. As water freezes, it releases a small amount of heat called the heat of fusion.  The continuous freezing of water on the plants and the subsequent release of heat keeps plant cells at a temperature at or near 32 deg F. This method is used on at-risk citrus and strawberry crops, among others.

Walking around the Seabright Area of Santa Cruz on Saturday, I stumbled upon the ‘Cruzian method for keeping your plants warm in freezing weather:

The Sweater Tree.

Apparently the Salinas Valley did see some snow this weekend. I hope growers aren’t finding too much damage to their crops as a result of the wintry temperatures.

[Misting method sources: the USDA and the University of Florida]

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