How to Grow Carrots in Illinois

Test your soil’s pH in an area exposed to full sunlight about one year prior to planting. Amend the soil with the test’s recommended amount of ground limestone to raise the pH to between 6.0 and 6.8, if you have acidic soil. If you have heavy soil, like most of Illinois, you will need to add about 8 pounds of ground limestone per 100 square feet to raise the pH by one whole point.

Work the soil 12 inches deep, using a rotary tiller or spade fork, as soon as the ground warms up and the threat of frost passes in the spring. Spread a 1- to 2-inch-thick layer of sphagnum peat moss, or 3.8 cubic feet per 90 square feet, over the soil surface if you have heavy clay soil and cultivate the soil again until it is finely tilled.

Plant your carrot seeds between April 10 and July 15 if you live in central Illinois. Plant seeds two weeks later if you live in southern Illinois. Plant seeds two weeks earlier if you live in northern Illinois. Plant the seeds in groups of two or three, and space them 1 inch apart in rows spaced 12 to 18 inches apart.

Water the soil 1 to 2 inches deep after planting, using a watering can for the task to prevent washing the seeds away. Keep the top 1 to 2 inches of soil moist at all times during the growing season, never allowing it to dry out.

Cover the rows with clear polyethylene greenhouse film and mound the soil around the edges just enough to keep it in place. Remove the greenhouse film as soon as the seeds sprout.

Cover the seedlings with 50 percent shade cloth if your area experiences a very hot summer, or when temperatures exceed 85 degrees Fahrenheit. Remove the cloth when the temperatures drop below 85 degrees Fahrenheit.

Cultivate the top 1/2 to 1 inch of soil, using a blade cultivator or hoe, to keep weeds at bay during the first two to three weeks.

Thin the plants out to 2 inches apart when the tops reach 2 to 3 inches tall. Always pull the weakest-looking plants when thinning, allowing the healthiest to remain.

Apply about 1/2 inch of shredded bark or shredded leaves over the soil after the carrots sprout, keeping a distance of about 1 inch from the stems.

Cover the carrot plants with spun-bonded polyolefin or polypropylene row covers to protect against carrot rust flies, leafhoppers and parsley worms. Carrots generally don’t have many pest issues, but in addition to row covers, crop rotation and planting disease-resistant cultivars helps prevent potential problems.

Harvest your carrots before they grow to 1 to 1 1/2 inches in diameter by pulling them from the soil by their leafy tops. You can harvest carrots at just about any stage of maturity. “Danvers” cultivars mature about 65 days after planting, “Bolero” mature about 70 days after planting and “Scarlet Nantes” mature about 70 days after planting.