Bruce Barr, of Barr Orchards west of Smithsburg, said the temperature at his farm Thursday night was two degrees colder than the day before.
"I can't find any good peaches," he said. "It looks like a total loss."
It was the third time in the last 12 years - the others were in 1985 and 1994 - that Barr suffered a complete loss, he said.
Barr said he still hopes he will be able to save some of his apple crop, which is not yet in bloom.
Steve Lewis, of Lewis Orchards and Farm Market in Cavetown, said he was not ready to declare a total disaster. He said he will not thoroughly inspect his crops for another day or too.
But Lewis acknowledged that the temperatures have not been kind. A chart he uses predicts a 90 percent peach and apple loss when the mercury drops to 24 degrees at this time of year. Thermometers throughout the orchard recorded temperatures as low as 19 degrees Wednesday night, he said.
Since apples and peaches account for 80 percent to 85 percent of his business, Lewis said a total loss would be disastrous.
"It would be pretty devastating," he said.
When a spring frost strikes, there is little farmers can do about it.
"It's one of the most uncertain things we have to deal with in our business," Barr said.
Sometimes, Lewis said, a thin layer of warm air hovers above the ground. When that is the case, he said helicopters can fly back and forth and push the warmer air down.
But he said it has been so cold the last two nights that there is no warm layer. Lewis said he is hoping for luck.
"Strange things have happened in the past," he said. "We're just hoping for the best right now."
Even if only 10 percent of the peach crop survives the winter-like cold, that's enough for a good crop, said Don Schwartz, Washington County's agriculture extension agent.
Farmers normally thin peach crops. This spring, Mother Nature might have beaten them to it, he said.
"We will see some damage on peaches, but we don't know how much yet," Schwartz said.
He said high winds might have prevented much of the damage to peach, cherry and apple orchards, by keeping the cold air from settling low around the orchards.
Early morning winds on Thursday averaged 6 mph, according to local weather observer Greg Keefer.
But the weather service predicted winds would diminish late Thursday night.
Farm Manager Frank Allnutt said if the winds died down Thursday night, wind machines would be turned on at the University of Maryland's Western Maryland Research and Education Center in Keedysville.
The research center already lost some blossoms overnight Wednesday when the temperature fell to 18 degrees, Allnutt said. The farm grows peaches, cherries and apples.
Other farmers might use smudge pots to protect their orchards against frost, Allnutt said. Smudge pots, which are fueled by kerosene, are placed in the orchard to warm the field.