Chilly spring nights, including those predicted for tonight and the rest of the week, are the kind that make peach growers such as Allan Baugher humble.
"You've invested all your time and efforts into a crop up to this point, and one goofy night can cause havoc," said Mr. Baugher, echoing the sentiments of local orchard owners who have been scurrying to protect their fruit from a freeze. "It keeps us on edge."
A cold front that is forecast to bring 20-degree temperatures to the area has many farmers worried that the nearly open blossoms on their peach and other fruit trees might die in the chill.
Last year, winter ice storms prevented buds from forming on some trees and burst the buds on others. In contrast, a late frost this spring could kill the almost mature blossoms and cause them to fall off the trees, said Mr. Baugher, who garners 20 percent of his income from peaches, cherries and other pitted fruits.
"We're a couple days of warm weather away from a full bloom," he said, noting that most of the buds are pinkish on the tips, indicating they are ready to spring open.
"The buds will take 25 degrees for a little while," he said. "I think it will do some killing, but won't wipe it out. It depends on how long it [cold weather] stays with us."
In preparation, many farmers have installed wind machines, as Mr. Baugher has, said Christopher Walsh of the University of Maryland's horticulture department.
A wind machine is a propeller attached to a 30- to 40-foot shaft that spins all night, driving the warmer air that has risen from the ground back down to the trees, he said. Each machine will protect about 10 acres of fruit, Dr. Walsh said.
"You're not going to go out and install one of these things tonight. But, if you've worried about this year in and year out, you will have installed a few of these," Dr. Walsh said, noting that Mr. Baugher has four of the $10,000 to $12,000 machines permanently installed in his orchard.
For the farmer who is slightly less prepared, helicopter pilots will offer their services for a few hundred dollars an hour to provide the same effect, he said.
"They do a very effective job," he said. "Some farmers have told me that if they fly over once a night, it mixes enough air that the cold front is broken for the rest of the evening.
The traditional method of heating the orchards with burning smudge pots and small brush fires is being discouraged because of environmental concerns, Dr. Walsh said.