By Debra Levey Larson
Media/Communications, University of Illinois College of Agricultural, Consumer and Environmental Sciences
URBANA, Ill.—Early spring gardening is a challenge for gardeners who gamble that the weather won’t be too cold, too wet, or both, said University of Illinois Extension Horticulture Specialist Richard Hentschel.
“There are some strategies that a gardener can try in order to come out on top and have a great garden, starting with your earliest plantings,” Hentschel said. “Learning when to plant is a matter of reading each seed packet or understanding the catalog lingo. No matter where you garden in Illinois, there can be an early garden planted. In the southernmost tip of Illinois, the planting date could be as early as the first week in April. The same planting date for early vegetables in northern Illinois can be closer to the first week in May. The difference in growing days from southern Illinois to northern Illinois is typically about 40 days.”
Hentschel said another thing to consider is whether you’ll be planting seeds or transplants. “If you would like the additional challenge, try growing the transplants,” he said.
“Another bit of needed information is the historical and somewhat mysterious frost-free date for the area you live in. Everything is referenced to that date for your first planting. These are very specific dates, yet each year the gardener will have to decide if it is better to postpone the planting one day or several,” he said.
“Southern Illinois has about 200 frost-free days, whereas northern Illinois only has about 160 days, and the rest of Illinois has something in between,” he said. “This information allows gardeners to choose vegetables that will germinate, grow and produce before the first freeze kills the plants.”
The usual lists of vegetables for the early garden are those that can survive evenings when you can still get a freeze. “The seeds in the ground won’t know if the air temperatures are below freezing or not,” Hentschel said. “These early spring vegetables prefer to germinate and grow in the cooler temperatures, or, like the potato, tubers prefer the cooler soil temperatures to get started, and the tops come up a bit later when the air temps are warmer.
“Some of the earliest vegetables grown from seed are leafy vegetables like kale, leaf lettuces of all kinds and spinach,” he said. “Transplants that can handle the cold air are broccoli and cabbage.
“Vegetables that prefer colder soil to start growing include asparagus, onion sets, rhubarb and potatoes,” he added. “This group of seeds and transplants go in the ground four to six weeks before the average frost-free date.”
Two to three weeks after planting very hardy vegetables, you can plant frost-tolerant vegetables, which can survive a frost but not a freeze, Hentschel said.
“Beets, carrots, Swiss chard, radishes and parsnips are good examples,” he said. “Transplants that are available by then include herbs, cauliflower and Chinese cabbage.”
Planting both very hardy and frost-tolerant vegetables can be a bit of a job as the garden soil is often still too wet. Sometimes it means digging an individual hole for the transplants and using dry soil set aside just for this purpose or using some bagged potting soil if your ground is too wet.
“A similar strategy can be used for the rows of vegetables you are planting. You can also use sand to cover the smallest of seeds if you feel the soil you have is too heavy,” he said.
“For vegetables like potatoes and asparagus, the plantings have to go in a lot deeper to accommodate tuber development for the potatoes and to establish a permanent planting of asparagus,” he said.
From the March 16-22, 2011, issue