MSU researchers test way to avoid frost damage in orchards

Jan 15, 2015

Spring came early in Michigan three years ago — very early — and fruit crops were later wiped out by frost. That has some researchers in Lansing asking if there's a way to delay the spring bloom in a warm year.

It's no secret what cause a cherry or apple blossom to come out in the spring — warmth. So if you want to slow down that process you just spray cold water on the tree.

An experiment done 40 years ago in Utah with automatic sprinklers delayed the spring bloom for three weeks. Jim Flore, a researcher at Michigan State University, says the sprinklers just rained continuously.

"Turn it on for five minutes, turn it off for five minutes," he said. "Let them dry out, and as a consequence, they used about 36 inches of water."

Using that much water is expensive and causes other problems, like disease.

New technology makes experimental methods more viable

So nobody thought any more about that work until the record-warm spring of 2012. That was the year trees bloomed more than a month early in Michigan, and when frost came, almost every blossom in the state was frozen.

Tree fruit crops across the state were almost totally destroyed.

That got Flore thinking about the spraying water study. He’s been experimenting with different methods for the last two years. He says new technologies have made this idea viable. Instead of sprinklers, he’s using misters, like you see spraying produce at the grocery store.

His team has worked out exactly how much moisture is needed to keep the buds cool.

"Now based on that, we can turn this system on and off, which saves a lot of water," Flore says.

But is the system worth the additional costs?

Flore says his experiment used less than a third of the water used in Utah in the 1970s. At that amount, problems like disease go away. His team delayed blooms as much as 10 days, which can make a big difference trying to get past the danger of frost.

Flore says installing a network of hoses and sprayers in an orchard will not be cheap, but he says the systems might also be used to spray pesticides.

"So then you don’t have to have ... the $70,000 speed sprayer and the $60,000 tractor to pull it around," he says.

Flore presented his work at the Northwest Michigan Orchard and Vineyard Show this week at the Grand Traverse Resort. He told growers he thinks a sprayer system could help them avoid frost damage and plans to study the idea for one more year.

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