Agricultural freezes are not dramatic disasters like hurricanes, tornados or wildfires.  Even if they occur on a large scale, whether or not crop sustains or escapes damage comes down to little details.  How cold it gets in a particular area is effected enormously by topography: especially slope.  Cold air flows downhill into valleys, draws, hollows and other low spots. Close proximity to water also helps as water is almost always warmer than air.  And only certain crops are affected.
Low temperatures through the Central Valley last week illustrated the importance of microclimates, with certain areas from Kern County to Red Bluff experiencing nights in the low 20s that almost certainly destroyed any almond or peach blooms.  Meanwhile, nearby areas reported temperatures hovering just below freezing — warm enough to save some or all of crop.
Water availability and type of irrigation will also end up being a critical factor.  Many farmers do not have access to irrigation water during the winter time.  Those that do were able to keep their orchards a few degrees warmer during the night, but only if they have sprinkler systems.  Many of the newest orchards in California use drip irrigation, which is great for conserving water but useless for frost protection.
At Terra Firma, we hit low temperatures of 26 degrees on two nights, although we were running sprinklers that likely kept the orchard a degree or two warmer.  The damage from the cold weather will likely be limited to just a few early-ripening varieties of peaches and nectarines that were further along in their bloom and thus more sensitive.

Checking those varieties today, I found a large number of tiny, shriveled fruit.  But I also found shiny, happy green fruit — often just a few inches away on the same branch.  It’s still very hard to get a good idea of how much fruit survived.  But it’s important to note that most years, our peaches and nectarines dramatically overpollinate, “setting” more fruit than the branches can bear.  So we have to remove half or more of the fruit, by hand.  It’s a time-consuming and rather depressing task.

Shriveled, frozen nectarine is on the left. On the right, a shiny green healthy fruit.

This year, Mother Nature may have taken care of some of the peach thinning for us.  Almond growers in the coldest areas are not so lucky: losing half your blossoms to a freeze means losing half your crop.
With the cold weather in the rear view mirror, we are shifting our sights to our first tomato plants.  They are going in the ground tomorrow!