Mother Nature Hands Fruit Farmers Weird Weather, Sleepless Nights

The unseasonably warm February weather in North Carolina accelerated the growing season for early-blooming strawberry and blueberry plants. But, it's also left them vulnerable, and recent cold weather has local berry farmers scrambling to protect their crops.

North Carolina has the third largest commercial strawberry industry in the U.S., worth roughly $25 million in 2015. The state also leads the nation in pick-your-owns, where the fruit is sold directly to customers at local stands. For those farmers, the perennial hope is that cooler weather in February and March will hold the crops back from flowering until prime picking season for consumers in late spring and early summer.

But this year, all bets are off. That's according to North Carolina State University extension specialist Bill Cline. He says temperatures in the 70s and 80s last month had plants flowering several weeks earlier than he's ever seen, leaving farmers scrambling to protect their crops as the thermometer dipped below freezing.

“A dormant plant will withstand quite cold temperatures, but once they go ahead and bloom, they're at increased risk," Cline says. "As the flowers develop and open, the more open they get, the closer you get to where a temperature close to freezing will damage them.”

He also notes there's only a four-degree window for the fruit growers to play with, and it's a potentially costly balancing act. Since plants are damaged at even slightly below 32 degrees, Cline says farmers often utilize row cover material—or even a double layer—that raises plant temperatures between 4 to 6 degrees. Another common strategy for freeze protection is to use overhead irrigation.

“As long as you constantly keep the plants wet, even though you're forming ice—ice itself is a very poor insulator, so it's not an insulating layer—but if you keep the ice constantly wet, then the ice and everything under it stays at the phase change temperature at 32 degrees Fahrenheit.”

The use of added irrigation proved effective for many fruit growers during last weekend's cold snap, but it comes with a cost.

“It's been such an unusual year with a lot of nights staying up and trying to decide how to protect, and what nights to protect,” Cline says. “And if you're using irrigation, are you going to run out of water eventually? Are your wells going to run dry from pumping so much? So, it's been some sleepless nights for a lot of fruit growers.”

Cline cautions that local farmers aren't out of the woods yet. Late freezes are not uncommon in the Piedmont. All it takes is a strong freeze in late March, or early April, and your next strawberry purchase may not be marked “Grown in North Carolina.”