COLUMBIA, Mo. –Gardeners eager to plant their first annuals and vegetables should be wary of a last spring frost.
“I tell people, if you plant early, plant only what you don’t mind losing,” said Mary Kroening, University of Missouri Extension horticulturist.
Garden centers often urge early planting to help sales, but gardeners should be patient, she said.
The average day for the last spring frost in Missouri ranges from April 5 in southern portions of the state to April 20 in northern areas, said Pat Guinan, MU Extension climatologist. But those dates are only averages, he notes. Jefferson City once recorded a May 26 spring frost, while Kirksville and Mexico have had May 25 spring frosts.
Other record late dates include Fulton, May 24; Cape Girardeau, May 17; Moberly and Columbia, May 9; and New Franklin, May 1.
Gardeners can check the average date for the last spring frost in their area at ipm.missouri.edu/FrostFreezeGuide/contourmaps/fall32_contours.cfm.
“Sometimes, if it is not a real harsh frost, you can get by covering the plants, but if the temperature gets down in the 20s, annual and vegetable plants will not survive,” Kroening said.
Sixty degrees is about the ideal soil temperature for planting. “Some people think they can plant summer bulbs into the soil and not worry about frost,” she said. “But the bulbs planted in too-cold soil just lie there and rot.”
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