In a cooler climate like Iowa’s, there are certain plants that benefit from being planted in early spring. Exposing perennials or vegetables to cooler temperatures, the plants are hardened and acclimate to the realities of cooler regions. Allowing edible plants like lettuce, spinach, radishes, carrots, and broccoli to mature in cool weather prevents them from becoming bitter tasting or bolting and producing seed, as they would during warmer weather.
With cool season planting, you must be aware of the temperatures that can change drastically during early spring. Most cool season plants can tolerate light frost, allowing gardeners to plant in low 30-degree weather or as soon as the ground is workable. If the temperature is expected to dip below 32 degrees overnight, Brucemore gardeners often move the plants inside. If the temperature will hover around 32 degrees overnight, you can also cover the plants with plastic sheeting or glass cloches (a bell-shaped glass that can protect plants from frost and force growth during sunny days). Perennials must be protected from the frost and brought inside.
Get a head start on the growing season at Brucemore’s Cool Season Plant Sale, April 10 through 12 from 5:00 to 7:30 p.m. in the Lord & Burnham Greenhouse. Brucemore staff and garden volunteers will be available to answer questions. You can also contact a Brucemore gardener at firstname.lastname@example.org for more information.