Several successive nights of freezing temperatures in California's San Joaquin Valley and in coastal growing areas have kept growers busy implementing costly frost-protection measures in the hope of preventing or minimizing damage to citrus, avocados and strawberries.
Some vegetable crops in the southern coastal areas may also be affected by the cold, but are said to be of less concern.
The coldest temperatures in most affected areas came early in the morning on Jan. 14. Industry sources are in agreement that it will be several days before the extent of any damage is known, but it is not expected to be widespread or to have a major effect on supplies.
It is "certainly not the worst" freeze the California citrus industry has experienced in recent years, "and I don't think at this point that it is even as bad as that event we had in January last year," Bob Blakely, director of industry relations for California Citrus Mutual in Exeter, CA, told The Produce News Jan. 14. "At this point, this is what I would call maybe a moderate event. We are still assessing the damage, but we don't feel like we have had the lows for the durations that would affect the Navel oranges, which are still the largest [citrus] commodity we have."
An estimated 75 percent of that crop is still on the tree awaiting harvest.
Mandarins are another matter, as that harvest is further along and "we do expect to see some damage to the remaining Mandarin crop, especially after last night," Mr. Blakely said. However, it probably will not be enough to "affect the overall season. One message we want to get out there is we haven't had widespread damage."
Consumers "should not expect to see a change in the prices they are paying at the supermarket" for California citrus, nor in the quality of the fruit they buy, he said. "And the quality has been outstanding this year."
A California Citrus Mutual press release dated Jan. 14 said that overnight temperatures Sunday "dropped steadily in the early evening to the low and mid-20s" in the San Joaquin Valley, while growers in Ventura, Riverside and Imperial counties saw "only a short duration" of temperatures below 32 degrees.
The extent of damage from four consecutive nights of temperatures ranging from the low 20s to the low 30s "will become clear in the coming days," the release continued. However, frost-protection measures such as wind machines and irrigation were "successful in raising temperatures above the critical levels for the Navel crop, which is expected to have incurred very minimal damage. The most damage will be sustained on border rows, but given the maturity and sugar content of the fruit at this point in the season, the extent of the damage will not be significant."
Mandarins and lemons, which are less frost tolerant, "will likely see moderate damage."
While the cold "was not catastrophic for the industry," it was costly, the release continued. Growers "spent a combined total of $17.5 million on frost-protection mechanisms." However, about $100 million was spent on frost protection at the same point in the season last year.
Avocado growers in San Diego and Ventura counties were also up for several successive nights working to protect their crops from frost damage.
Tom Bellamore, president of the California Avocado Commission, told The Produce News Jan. 14, "We really won't know the extent of the trouble, if any, for a little while to come."
Pockets of "very cold air" were seen in some growing areas. Temperatures dropped to 23 degrees in some spots, but temperatures in the high 20s for extended periods were more common. Most groves hovered around the freezing mark.
"We have 60,000 acres, and usually when a significant frost event occurs, it will impact a portion of that acreage," he said. But most of the crop should escape harm, "and we expect to send a pretty good crop to market. We don't really anticipate that there will be a major dent in supply, but we will know for sure here in a week's time."
Southern California strawberry growers were "busy with all kinds of weather-mitigation practices" from wind machines and helicopters to orchard heaters.
"I know guys that have hardly had any sleep since last Thursday or Friday," Carolyn O'Donnell, communications director for the California Strawberry Commission, said Jan. 14. "Unfortunately, with strawberries you don't really know how much damage you've got for a week or two. It doesn't show up right away."
Ms. O'Donnell expects that damage "will be isolated" and will be more severe in certain spots "because some fields have a different kind of microclimate."
Ventura County Agricultural Commissioner Henry Gonzales told The Produce News that there is little concern for vegetable crops except, perhaps, in newly planted fields where the transplants "are not quite established yet." Usually vegetables are "a little bit more durable" than strawberries, avocados and citrus, all of which are grown in Ventura County.
Established vegetables grown year-round in Oxnard, such as celery, shouldn't be adversely affected, he said.
Citrus in the Ojai Valley is the area of greatest concern in the county, "because there are some really cold spots there," Mr. Gonzales said. "The rest of the Oxnard Plain is not a concern at this point."