Thin-skinned citrus like mandarins tend to be susceptible to cold damage, while thicker-skinned varieties like navels are more cold-hardy, withstanding temperatures as low as 27 degrees. High sugar content can also increase a fruit’s cold tolerance.

While a certain amount of cold helps the sugars in citrus develop, too much for too long can destroy a crop. Ice forms inside the fruit’s tissues, causing them to burst. As the fruit loses its moisture through the broken membranes, it begins to dry out. “The flavor changes, it gets bitter, and it’s not as juicy,” says Tory.

Fending Off the Freeze

Damaged citrus fruit. Photo by Tory Farms.

Citrus farms have various frost protection strategies in their arsenal, but most are costly and can be a heavy drain on energy and resources. Larger farms may use orchard heaters or wind machines that pull warm air down into the grove, creating an “inversion layer” that raises temperatures by five or more degrees. Such machines rely on natural gas, diesel, or propane.

On the low-tech end of the spectrum, farmers can run sprinklers directly on the trees, creating an ice layer that buffers fruit through a phenomenon known as “heat of fusion.” Farmers can also flood their orchards to retain warmth and create an insulating fog or steam.

Watch this video by farmer Nigel Walker of Eatwell Farm.

But such water-intensive methods can only raise temperatures by a degree or two, and they are not ideal for arid California, especially during what could be the worst drought in four decades. “We ran water in our orchards every night for a month to help protect the trees, and our biggest concern right now is water,” said Yukio Hamada of Hamada Farms. He estimates that they lost 30 to 50% of their citrus during the freeze.

“There’s still good fruit out there, but we’ve got to be selective, and that takes a lot of time because we do all of our picking by hand.” While some larger packing houses have machines that can sort out bad fruit, many farms manually inspect by piece, cutting samples to check for damage or floating fruit in water.

Orange Juice Out of Oranges

Rebecca and Tory Torosian. Photo by Gary Yost Photography.

Large citrus growers have been selling off damaged citrus for juicing to recoup harvest costs, an option that may not be available to farms with smaller quantities of fruit. “I think we’re small enough volume that it would be hard to get any interest,” says Ted of Blossom Bluff.

Overall, citrus represents less than 10% of Blossom Bluff’s business, but evaluating the costs of labor and resources invested in their citrus is difficult on a farm that has more than 125 varieties of fruit. According to Ted, “It’s the intangible losses that are going to affect us the most: continued contact with customers and employment of our workers throughout the winter.” Blossom Bluff will dry some of their mandarins, but “there is a limited amount that you can do.”

Planning for the worst, John Lagier and Casey Havre of Lagier Ranches got much of their citrus off the trees a few days before the frost hit. They were able to salvage their Meyer lemons to process into spreads for Saint Benoit Creamery’s yogurts. They have also been selling their cold-damaged mandarins at a discount for juicing, which has helped them to recover some of their losses. “You do what you gotta do,” says John.

For these small farms, diversification, year-round planning, and flexibility are the keys to survival. “We’re just going to wait and see what happens,” says Tory of Tory Farms. “Our stone fruit is in dormancy, and it loves the cold. We’re like gamblers. We’ve got all our bets covered.”

citrus freezecitrus freeze

Big Chill for California Citrus Growers