Returning Cold Weather Is Good News For Wisconsin Fruit Growers

Wisconsin fruit growers are cheering the return of lower temperatures after last week’s unseasonably mild conditions. They say trees are still dormant at this point in the year, so the return to cold weather isn’t likely to hurt fruit crops and buds the way a cold snap in late spring might.

But fruit trees need a certain number of so-called “chilling hours” to be ready for growth in the spring and after a warm spell, plants do lose some of their ability to tolerate cold.

And stretches of warm weather can put trees at risk of damage if they’re followed by extreme cold weather, said Deirdre Birmingham, who runs the Cider Farm near Mineral Point.

“They start to reduce some of their dormancy,” she said. “It certainly messes with them; it’s almost like people and their wardrobes. You get confused. Are you supposed to wear winter clothes, or summer clothes or spring clothes?”

Cold tolerance is a dynamic process for plants, said Amaya Atucha, state fruit crop specialist with University of Wisconsin-Extension.

She said if more typical winter temperatures come back, so will that hardiness.

“They can regain that ability, so at this point what is happening on the buds of those fruit crops and those vines is that they are reacclimating,” Atucha said. “They’re gaining their ability to withstand cold temperatures again.”

While the recent temperature swings aren’t expected to affect the state’s fruit crops on their own, growers do have a long-term concern. They say the state has seen several such swings over the last few winters, and the ongoing stress from those changes can lead to long-term damage for fruit trees.