COLUMBIA — Gardeners eager to plant their first annuals and summer vegetables might want to hold off until Mother’s Day, said Mary Kroening, a MU Extension horticulturist.
Kroening said gardeners should shoot for Mother’s Day — which falls on May 11 this year — to plant summer vegetables since no frost has been recorded in Columbia beyond May 12.
“A lot of people hear that April 15 is the average frost-free date in mid-Missouri,” Kroening said. “But April 15 is only the average frost-free date. Fifty percent of the time you have no frost after that date and fifty percent of the time you can still have a frost.”
Kroening said cool season crops such as peas, beans, lettuce, spinach and beets can be planted from mid-March to mid-April, but summer vegetables such as tomatoes, peppers, squash and cucumbers are at a higher risk for frost damage.
Emily Moore of Superior Garden Center in Columbia said one of the biggest problems this season has been the unusual amount of rainfall.
“It’s too wet to be digging,” Moore said. “It’s too early for a lot of vegetables, but we have sold a lot of plants like pansies and ornamental kale that can take cooler weather.”
Kroening said 60 degrees is the ideal soil temperature for planting. Soils in mid-Missouri are still well below that temperature.
“People think you can plant your summer bulbs into the soil and not worry about frost because bulbs are not going to grow yet,” Kroening said, but bulbs planted in cold soil lie in the ground and rot.
“Sometimes you can get by covering the plants, but if the temperature gets down in the twenties, annual and vegetable plants will not survive,” Kroening said. “I tell people if you plant early, plant only what you don’t mind losing.”