Better cover the tomato sets for another night because the big chill that sneaked into the Mid-Columbia's fruit orchards is expected to linger through tonight, too.
Freezing weather has fruit growers on the alert to protect cherry blossoms and early buds on apple trees.
Denny Hayden of Hayden Farms in Franklin County said the cool spring may take a small toll on this year's fruit harvest, but it isn't unexpected for this time of year.
"We had hoped for a later spring because of last November's cold snap. We've got damaged (tree) tissue recovering," Hayden said.
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Sunday's cold, followed by another mid-20s night Monday didn't catch the growers unprepared, however.
John Pringle, who has a cherry orchard in full bloom south of Kennewick at Garfield Street and 50th Place, said he isn't too worried. He has smudge pots in place and ready to go, and wind machines set to start as soon as night-time temperatures touch 32 degrees.
"It's a full moon and Easter week," Hayden said, as if the coincidence of the high holiday and a bright night had something to do with cold weather.
"So far it's been a typical spring. There will be damage here and there," he added.
Cherry trees are most vulnerable to the cold because of fragile blossoms, but apple trees also are vulnerable, he said.
Also of concern is the bee pollination of trees.
Hayden said his orchards had three bad days last week when the pollinators were not active. But Saturday's warmth brought out the bees, and Sunday was cooler, but still good. Monday's splotchy skies let enough sunshine through to get the bees moving again, Hayden said.
The off-and-on nature of this delayed spring is better than a rush into warm weather, Hayden said.
"We're an early area for cherries here in the Tri-Cities, and we need this cool spring. We had hoped for it," he said.
Better to have a more temperate entry into the growing season than see a heat-induced growth spurt.
"We don't need temperatures in the 80s now. That would put a stress on the trees," Hayden said.
The cold that is predicted to linger in the Mid-Columbia all week could see lower-lying areas that are sheltered from wind experience low to mid-20s tonight, said Jim Holcomb, a forecaster with Clearwest Ag.
An inversion layer that positions warm area above the cold pockets can help farmers who use wind machines to blow the warmer air into low-lying orchards.
Farmers also can provide supplemental heat generated by smudge pots or spray water onto trees as a strategy to keep the cold from penetrating into the buds, said Bud Graves of Clearwest Ag.
"Potentially there could be a need for pretty heavy overhead protection" the next few days, Graves said.
But the key to effective water spraying is to keep applying the water so the trees remain wet until temperatures rise.
If the temperature remains at freezing or below and the spray of water stops, the freezing process takes hold of the tree, drawing heat from it through condensation, Graves explained.
"You've got to keep everything wet," he said.
Pringle said he isn't too worried because by the inversion layer.
Hayden agrees: "Last night was predicted to be bad, and it wasn't," he noted Monday.
-- John Trumbo: 509-582-1529; firstname.lastname@example.org