Frost in the Almonds — February 2022

Three frosts hit the almond growers this week. Hard freezes aren’t all that common in almond land at any point in the winter. When it does freeze, it usually occurs in December or January, not during the bloom and nutlet stages that unfold in February and March. As I wrote in the previous post, the orchard where our bees work had a difficult 2021 due to water scarcity. Frost damage is the last thing they needed to deal with in 2022, especially since this year is starting dry already. It will take several days before we find out if crop loss due to the frosts was significant.

Since we only witness what is happening in the orchards during several weeks of the year, I keep a pretty close eye on the Blue Diamond Crop Progress Report early in the year. Billions of dollars are tied up in the 1.6 million acres of almonds planted in the central valley, so a lot of folks have some kind of stake in tracking the temperatures, bloom patterns, and “bee activity” reported in these reports. These are the details that matter in producing 80% of the world’s almonds.

The most recent crop report has informative details about frost suppression in almond orchards and the current damage outlook. The use of helicopters is perhaps the most remarkable piece of frost protection in the almonds. It’s fairly common for the air above the orchards to be a few degrees warmer than the orchard floor, so creating a downward air current to push the warmth to tree level can save the crop. I have no idea how much it costs to rent helicopters! A more familiar frost protection tactic is the use of water. Saturating the orchard floor helps hold heat through the night compared to dry earth, and running sprinklers during the freeze can force the water to absorb much of the cold rather than frosting plant tissues (thereby protecting the vulnerable blossoms and nutlets).

These temperatures show mortality rates for different almond varieties at various temperatures. The nutlet phase is most vulnerable.

A grower cited in the report wrapped things up in this statement: ‘“This year’s bloom started a little earlier than last year but finished faster. On February 11 we were at 1% bloom, in the next 36 hours in jumped to 50% bloom,” said Traver and Reedley area grower Anthony Balakian. “We survived last night’s frost and do not think any damage will show up. The next two nights should be a little warmer and then hopefully we are done with frost for this year.”

The northern orchards around our bees were actually ahead of the southern and central locations. We were slightly past peak bloom on February 13 when we first rolled in during 2022 pollination. That was remarkably early. We will hope they fared well–that orchard’s water supply looked good, so I’m sure some of it was deployed to protect against the frost. Pollination temperatures were great, so we should have set a good crop if the freeze wasn’t too brutal and the water holds out.