Local avocado, citrus growers are preparing for frost — and you should, too

Local fruit growers are preparing for a potentially chilly weekend across San Luis Obispo County, with low temperatures and drought-stressed trees putting some of the county’s crops at risk.

Of primary concerns are local avocados and citrus — both notoriously sensitive to cold conditions and frost damage. Those crops also represent significant cash crops in the county: in 2015, oranges and lemons were valued at close to $17.7 million, and avocados were valued at $16.7 million.

“You could lose thousands and thousands of dollars in one night if you aren’t careful,” said Launnie Ginn, support tech for the Cal Poly Horticulture and Crop Sciences Department. Ginn oversees Cal Poly’s crops, including its roughly 25 acres of citrus and 20 acres of avocados.

The concern isn’t unusual: Early December is usually one of the riskiest times of year for the sensitive fruits as cold weather hits quickly and some growers don’t have time to prepare, Ginn said.

So far this year, there have been no frosts on campus, Ginn said, noting that wind has kept the temperature above freezing in the coastal corridors where citrus and avocados are grown.

That will likely be the case this weekend, he said, but just in case, he plans to be monitoring the situation from his on-campus home. If the temperature drops, he’ll turn on the field wind machines that help stir the air and keep it those few essential degrees above freezing.

“It’s usually enough just to keep it windy,” he said.

Next week could be a different story, when another cold snap is expected to hit, bringing the temps down to lows in the 20s. Then they might need to bring out the big guns, i.e. the “frost dragon” — a set of propane tanks and fans that blast hot air throughout the crops, he said.

San Luis Obispo County Chief Deputy Agricultural Commissioner Brenda Ouwerkerk said her office has received no reports of frost damage to citrus or avocado crops this season, although she did caution that this year’s crops could be at heightened risk because of the ongoing drought (irrigation water is often used to help release heat and prevent frost in fields).

“Freezing temperatures are always a worry to growers, and trees are already compromised in some areas of the county due to lack of irrigation water because of the ongoing drought condition,” she said Friday. “A hard frost would not be good for these stressed trees.”

This story was originally published December 2, 2016 at 7:43 PM with the headline "Local avocado, citrus growers are preparing for frost — and you should, too."