Area farmers prepare crops for a frost

Posted: May 14, 2013

The Winchester Star

Protective covers have been placed over rows of newly planted peppers at Mackintosh Fruit Farm northwest of Berryville to protect the young plants against colder-than-normal weather. (Photo by Scott Mason/The Winchester Star)
A water sprinkler stands above young strawberries Monday afternoon at the Mackintosh farm. A protective coating of ice would protect the berries from freezing temperatures.
A agricultural fan stands behind a row of cherry trees at Mackintosh Fruit Farm northeast of Berryville. The fan is used to keep cold air from settling over the young cherries. (Photo by Scott Mason/The Winchester Star)


Bill Mackintosh’s alarm clock was set for 1 a.m. today, so he could check the temperature outside his Clarke County home.

As the owner of Mackintosh Fruit Market on Russell Road, he fears a frost or freeze at this time of year.

The prospect keeps him up all night, worrying about his most vulnerable plants.

“We’re lining it up like we are going to get a frost,” Mackintosh said on Monday. “We’ve got everything in place.”

Overnight temperatures were expected to drop into the 30s in the Shenandoah Valley, according to Kevin Witt, a meteorologist with the National Weather Service in Sterling.

He predicted that most areas would bottom out at 34 to 37 degrees, but the northwestern quadrant of Frederick County might dip as low as 32 or 33.

If the thermometer outside Mackintosh’s house falls to 36 degrees, he’ll fire up the wind machine in the orchard and turn on the water sprinkler system over his strawberry beds and pepper plants.

Spraying water on the strawberries can actually protect the fruit from cold air, he said. And the wind machine pulls warmer air down to raise temperatures around the crops.

The threat of a late frost sends tremors through farmers dependent on cash crops and gardeners nursing along the tomatoes and eggplants that will feature prominently on summer dinner tables.

Bobby Clark, agricultural specialist for the Virginia Cooperative Extension Service, said May 15 is typically the cutoff date for the last spring frost in the northern Shenandoah Valley.

“Believe it or not, we’re still within the freeze window,” he said.

Some crops can withstand a nip of frost, Clark said, such as early peas, lettuce and corn, but tomatoes and green beans can be easily killed by a cold snap.

Those who want to protect their plants should cover them, he said, adding that an old cotton bedsheet will do the trick.

Plastic also can be used as long as the material does not touch the plant, Clark said, because cold air can send a chill through synthetic material.

For commercial fruit and vegetable growers, accurate weather predictions are the difference between a good growing season and a bad one.

Mackintosh said he takes his cues from weather reports originating in Hagerstown, Md., because he finds them reliable for Clarke County.

Over the years, he has made some serious investments in machinery to help stave off Mother Nature’s attempts to kill his young plants.

He has a wind machine to move air around in his orchards — cold air settles to the ground, while the air higher up can be several degrees warmer. The machine helps to push the warmer air to the ground.

“Peaches are especially susceptible [to frost] when they come out of the ‘shuck,’ the hard covering of the flower,” Mackintosh said.

Cold can kill the infant fruit or scar it.

Nectarines and cherries also are vulnerable to the cold, but apples are less so.

The long, cool spring has put much of the spring crop behind schedule, Mackintosh said.

“We don’t have very many red berries,” he said of the strawberries that usually signal the beginning of his popular pick-your-own business, which he hopes to open May 22.

Despite nippy overnight temperatures, readings should “rebound pretty nicely,” Witt said, with overnight lows tonight in the low to mid-40s

Looking ahead through the Memorial Day weekend, lows should remain in the 50- to 60-degree range, he said.

— Contact Val Van Meter at