Carrots are in the Umbelliferae family, meaning they’re related to celery, dill, and parsley. They were first cultivated as medicine, not food, 5,000 years ago. Though they are hardy biennials, most growers treat them as annuals for root crop production.
Carrots are categorized into groups by root length and shape. Nantes type carrots are six to seven inches long with a blunt tip and a diameter around 1.5 inches. They have a small core, delicate tops, and are the type most preferred by home gardeners. Imperator type carrots are the primary commercially grown carrot type. Uniform and high-yielding, Imperator type carrots are large, seven to eight inches long, with a woody core at full maturity. Their above ground tops are fuller as mechanical harvesting utilizes the tops to pull the crop from the soil. Chantenay type carrots are shorter, at five to six inches long, but maintain their roughly two inch diameter down the length of the crop. Danvers type carrots are more conical with a top diameter around two inches and roots growing to a length around seven inches. Oxheart type carrots are smaller with roots growing two inches in diameter and two to three inches down. Oxheart carrots excel at growing in heavy, clay soil.
Carrots grow best in loose soil high in organic matter and deep enough for the roots to reach optimum length. Roots grown in heavy clay soil or soil rich with stones or other obstacles may grow to be forked, twisted, and stubbed. Carrot seeds can be sown in spring when the soil reaches 45°F and fall carrots can be direct seeded ten to twelve weeks before the last frost. Carrots perform best when grown between 55-75°F as higher temperature stunt root growth.
Seeding carrots is often considered the hardest part of growing carrots. An exclusively direct-seeded crop, plant carrot seed ⅓ to ⅕ inches into the soil with no more than three seeds per inch of row feet. Space rows 12 to 18 inches apart. The seeds can take one to three weeks to germinate and require consistent moisture during the entire germination period. Seeds may not emerge uniformly and can take time to establish. Considering these inconsistencies, farmers often plant a radish seed every six inches to locate a row of tiny carrot seedlings. Quick growing radishes should be harvested before they compete with the main carrot crop. Should the soil crust over before the carrots have had the opportunity to germinate, higher populations of radish seed will help to break up the crusted soil, allowing the carrot seeds to emerge. Established carrot seedlings should be thinned to one to three inch spacing within row, depending on variety and end-use.
Stop by your local farm supply store and find a carrot variety that interests you. Whether they’re short, long, white, purple, or a bugs-bunny classic, fall planting time is here.