Running wind machines are one of the freeze protection measures growers employ. ( Photo courtesy California Citrus Mutual )

Back-to-back nights with temperatures in the 20s had California citrus growers taking steps to protect their fruit.

California Citrus Mutual president Joel Nelsen said he had never seen a freeze this late in the season in his 30-plus years in the industry, but there is little concern about damage to the current crop because fruit on the tree is mature, with thicker skin that can withstand cold.

Temperatures hovered in the low 20s for as long as five hours the night of Feb. 19. California Citrus Mutual reported in a news release that growers started with freeze protection measures that morning, running water in groves to keep the orchard floor moist and using wind machines to bring up temperatures. Some companies started wind machines as early as 10 p.m. that day, and on average growers ran them for eight hours.

The night of Feb. 20 brought more of the same, with temperatures two or three degrees warmer than the previous night.

Growers still employed freeze protection measures but not for as long, Nelsen said Feb. 22.

In an earlier news release, the organization mentioned the possibility of the cold affecting the 2018-19 crop because warmer-than-usual temperatures the past few weeks have prompted trees to start blooming 2-4 weeks sooner than normal.

Big swings in temperature — from “spring-like” to the 20s, for instance — can cause the young blooms to drop, per the release.

Nelsen said Feb. 22 he was optimistic that the overall effect will be minimal, with plenty of time for a tree to rejuvenate if damage occurred.

The extent of any damage to the 2018-19 crop will probably not be known until the end of March, Nelsen said.

About 50% of the current crop is still on the tree.