The next few weeks are an ideal time to plant tender annuals and garden vegetables, with the end of a late freeze risk in central Ohio.
Plants that you find at garden centers are acclimated to the cooler weather through exposure to the elements and should do just fine in your backyard.
However, greenhouse plants that are more sensitive to the cold (tomatoes, peppers, summer annuals) may experience slow growth initially, until they adapt to the upcoming cooler nights and cool, moist soil, according to Dr. David Shetlar, an Ohio State University entomologist.
Our thick clay soils are currently damp and have few air pockets, which Shetlar says are essential for “good root growth.” Better to keep the soil loose around the root ball and “spade in an inch or two of compost to add organic matter,” which creates separation between the clay particles, so the root system has space to develop.
Shetlar recommends raised flower beds.
“The simplest way to make raised beds is to use 2 by 10 or 2 by 12 lumber to make 3- to 4-feet wide by 4- to 6-feet long frames. Level these to the terrain and fill with commercially available soil. Raised beds tend to warm faster in the spring and allow you to get a head start on vegetable plant growth,” added Shetlar.
For the normally cooler eastern Ohio Valley areas, prone to late frost on clear, calm nights under Canadian high pressure, you may want to hold off on your tomatoes and peppers until after May 20, sticking to peas and cabbage and broccoli, among other cool-season crops.
Shetlar passed on an important reminder that gardeners carefully check vegetable plants for subtle signs of pest infestation.
“Many places are now selling ‘organic’ plants, which means that they haven’t been treated with insecticides, miticides or fungicides,” Shetlar said. “Unfortunately, this means that the plants may have some insects, mites or disease problems that are difficult to see on actively growing, young plants. Traditional plants have been treated with insecticides to take out aphids, whiteflies and thrips, but this means that twospotted spider mites may be present.”
Although he is not worried about thrips, which are normally in the environment, Shetlar advised inspecting the leaf undersurface for aphids or whiteflies.
Examine the upper surface of the leaves for tiny yellow or white speckles, which would indicate spider mite feeding.
“I’m most worried about spider mites as the ones that come from commercial plant producing facilities that are often resistant to one or more categories of miticides. So, if you bring them to your garden, you’ll be fighting them for the rest of the summer,” Shetlar said.