County farmers put strawberries on ice
By Bonnie Edwards
Published in News on April 9, 2007 1:46 PM
An alarm sounds in the middle of the night in E.L. Smith's bedroom when the temperature outside drops to 36 degrees.
"If the alarm goes off, I go to running," said the strawberry grower.
But Saturday night, Smith was ready for Jack Frost. He started his sprinklers before the sun went down.
"When it gets cold, I already know to have the sprinklers going," he said.
The losses in his more than an acre of strawberries could climb into the thousands if the frost were to hit the blooms and berries. Although the plants would probably survive, he said he could lose many weeks of production in that one night.
"When the temperature gets to 36, I start watering and don't cut off the sprinklers until after 9 or 10 the next morning," Smith said. "They say it's safe to turn them off when you can see the ice start to slip off on its own."
The weather switched from highs in the 80s Wednesday to the 60s Thursday and the 50s Friday. Lows dipped to 28 degrees Saturday and started climbing to 35 Sunday night.
Although 32 degrees is freezing, frost can appear at 34 degrees, said Kevin Johnson, crop agent with the Cooperative Extension Service.
The overhead sprinklers start wetting the plants before the temperature drops and put a coat of water on the leaves, stems, blossoms and young fruit. The mist from sprinklers forms a coat of ice that acts as an insulation barrier that protects the plant from damage from temperatures at 32 degrees and lower. This coat of ice protects the plant through the night with a layer of ice that acts like an igloo, trapping in the plant's own heat.
Frost will take the heat out of the plant, turning the blooms black and bruising the berries, Johnson said.
"It's neat how that works," he said.
It doesn't get as cold in Wayne County as it does in some places people grow strawberries, where the temperature can drop to the low 20s, he added.
Some growers have told Smith their sprinklers froze.
When the forecast in Raleigh is 28 degrees, it could end up being 30 around Wayne County, Johnson said.
Wayne County's strawberry crop is a little bit ahead of schedule because of unseasonably warm weather. Usually, Smith said he can begin harvesting April 20. He said it looks like his berries will be ready April 15.