How to Grow Carrots

Start with the soil, because the root grows straight down

A carrot is one long taproot, and anything it hits on the way down shows up in the harvest. Stones and clods bend it, heavy clay forks it, and a hard layer a few inches down stops it short. Clemson Extension notes that carrots in heavy clay grow poorly and come out forked or misshapen, and Texas A&M AgriLife adds that they also mature more slowly in heavy ground.

Prepare the bed before you buy seed:

• Loosen deeply. Texas A&M recommends working the soil 8-12 inches deep. Wisconsin Extension says to break up any compacted layer at 6-8 inches. In heavy soil, Utah State suggests double digging and adding plenty of compost.
• Clear it. Rake out rocks, clods and old roots.
• Raise it if you have clay. A raised bed filled with loose, sandy or loamy soil is the most reliable fix. UF/IFAS recommends raised beds for the best carrots in Florida, and Wisconsin notes they improve both drainage and root shape.
• Go easy on compost and nitrogen. Utah State caps compost at about 1 inch per 100 square feet. Wisconsin warns that too much nitrogen gives you big tops instead of roots.
• Check the pH. Clemson limes to pH 6.0-6.5 for root crops, while Wisconsin finds carrots grow well anywhere from 5.5 to 7.0. A soil test tells you whether you need to do anything.

If your soil is shallow or stubborn, match the carrot to the ground instead of fighting it. University of Maryland Extension describes Chantenay carrots, which are short and broad at the shoulder, as better suited to shallow, heavy soil than long, slim Imperator types. Round or stump-rooted carrots suit clay and containers. Long Imperators need deep, loose sand or loam to reach full length.

Carrot types and varieties for your region

The four classic shapes are Imperator (long and tapered), Nantes (cylindrical with a blunt tip), Danvers (conical, medium length) and Chantenay (short and wide). Several extension services name specific varieties for their own states:

• South Carolina (Clemson): Apache, Camden, Chantenay, Danvers 126 and Orlando Gold.
• Texas (Texas A&M AgriLife): Danvers 126, Danvers Half Long, Imperator 58, Nantes, Nantes Half Long, Red Core Chantenay, Royal Chantenay, Scarlet Nantes and Sugar Snax.
• Wisconsin: long types A Plus, Imperator, Ingot, Orlando Gold, Savory and Scarlet Nantes; half-long Artist, Lucky B, Nantes, Nelson, Pioneer and Red Cored Chantenay; baby carrots Little Finger and Minicor. The list was written for Wisconsin market growers.
• Florida (UF/IFAS): UF recommends types rather than named varieties: Imperator, Nantes, Danvers and Chantenay all do well there.

Utah State says most varieties sold in garden centers do well in Utah, so in the intermountain West, choose by root length to suit your soil.

Timing: cool weather makes the carrot

Carrots grow best when the air averages about 60-65°F (Clemson; Wisconsin puts it at 59-65°F). Above that, roots go short, blunt, coarse and strong-flavored. Below about 50°F for too long, the plant may decide it is in its second year and send up a flower stalk. Wisconsin says carrots flower after 6-8 weeks below 50°F, and Utah State links first-year flowering to sowing too early. Good timing means fitting the crop between those two limits.

Spring. Sow from about three weeks before your last frost up to the frost date. Sources differ a little here: Utah State says 2-3 weeks before the frost date, and Colorado State says 0-2 weeks before, because it counts carrots as only semi-hardy. Soil temperature is the better guide. Utah State says seed can go in once the soil reaches 40°F, while Maryland waits for 45°F. Colorado State measures soil temperature 4 inches deep at 8 a.m. The point of an early start is to have the roots dug before summer heat, so don’t push spring sowings late.

Fall. Nebraska Extension notes that cool-season crops maturing in the shorter, cooler days of fall often do as well as or better than spring plantings, and Illinois Extension adds that carrots get sweeter as the ground chills. Maryland sows fall carrots 10-12 weeks before the first frost. Purdue counts back the variety’s days to maturity from the frost date, and Nebraska adds about two weeks to that because growth slows in fall. The dates for your zone above are based on this count-back. The when to plant carrots page explains how to adjust them.

Succession. For a steady supply, sow again every 3 weeks (Wisconsin) or every 4 weeks through midsummer (Utah State).

Sowing: getting a stand is the hard part

Most carrot failures happen before the seedlings show. The seed is tiny and sown shallow, and it takes 2-3 weeks to come up; Utah State gives 14-21 days at good temperatures. If the surface dries or crusts during that time, the seedlings die or can’t break through.

1. If the soil is dry, water lightly a day or two before sowing (Nebraska).
2. Mix the seed with dry sand so it spreads thinly and evenly, as Clemson suggests. Fewer clumps means less thinning later.
3. Sow 1/4 inch deep in rows 12-18 inches apart. Wide bands or beds work too.
4. Cover with about 1/8 inch of vermiculite, sawdust, compost or potting mix instead of garden soil. Clemson and Utah State both recommend a loose cover because it holds moisture and does not crust.
5. Drop a few radish seeds in the row. They come up in days, show you where the row is, and break any crust (Utah State; Maryland).
6. Water gently and keep the surface damp until the carrots are up. In dry weather that can mean a light watering every day until the seedlings are established (Maryland).

Germination is best at 55-75°F soil temperature (Clemson; Utah State says 55-65°F). It falls off above 80°F, and Clemson says carrot seed will not sprout at all above 95°F. Late-summer sowings need extra care: shade the row with a board propped on bricks, and remove it as soon as sprouts appear (Nebraska).

Thinning: the step people skip

Crowded carrots stay thin, and roots that press against their neighbors grow misshapen (University of Maryland). Thin when the seedlings are 1-2 inches tall (Clemson) or have 3-4 true leaves (Utah State), leaving 2-3 inches between plants. Texas A&M thins in two passes: first to 2 inches when the tops are about 4 inches high, then to 4 inches as the roots fill. Snip the extras at soil level with scissors instead of pulling them, so the roots you keep are not disturbed.

Watering, feeding and weeding

Water evenly. Most carrot quality problems come from swings in soil moisture. Dry soil followed by a soaking splits roots, uneven moisture makes them coarse and strong-flavored (Clemson), and overwatering gives hairy, forked roots (Utah State). Clemson recommends watering deep enough to wet the top 6 inches, in the morning so the leaves are dry by dark. Drip irrigation and a mulch between rows make steady moisture much easier. Maryland eases off watering as harvest nears, because a flush of water on mature roots splits them.

Feed lightly. A soil-test-based preplant fertilizer is usually enough to start. Side-dress once with nitrogen when the tops are about 4 inches tall (Clemson) or 6 weeks after emergence (Utah State). Utah State uses about 1/4 cup of 21-0-0 per 10 feet of row, placed beside the plants and watered in. Sandy soils and heavy rains may call for a second light feeding (Clemson).

Weed early and shallowly. Carrots compete poorly with weeds, and Utah State stresses weed control most while the seedlings are germinating and getting established. Hand-pull in the row and hoe only the surface between rows, since deep cultivation cuts roots. Clemson and Maryland both rely on organic mulch for weed control once plants are up.

Cover the shoulders. Roots that push above the soil turn green on top. Pull soil or mulch over any exposed shoulders (Maryland; Wisconsin).

Regional differences

Cold North and upper Midwest. Wisconsin sows carrots around April 15 in the south of the state and in late April in the north. Fall carrots do especially well: they tolerate light frosts, and Nebraska and Utah State both describe leaving the roots in the ground under a heavy straw mulch and digging them as needed into winter. Aster leafhoppers ride north on spring winds from the Gulf states (Wisconsin) and spread aster yellows, so row covers matter more here than many gardeners expect.

Humid South and Southeast. Spring comes on fast, so sow early. Clemson’s coastal South Carolina sowings run from mid-December through January, with a second crop sown in late summer. Warm, wet weather favors Alternaria leaf blight (Wisconsin), and Clemson flags root-knot nematodes, which leave knotted roots (Texas A&M). Rotate where carrots grow, water in the morning, and consider summer soil solarization (UF/IFAS) where nematodes are a known problem.

Arid West and high plains. Utah State considers most of the state’s light soils well suited to carrots. The challenge is heat. Mulch to keep the soil cool, use drip irrigation, and water more often when temperatures pass 85°F, which is when roots start to lose color. In the low desert around Phoenix, carrots are a cool-season crop sown from late summer through early spring, and nothing goes in during the hottest months.

Pacific Northwest. Mild winters allow a second crop. Washington State University’s planting calendar for the region includes a mid-August sowing of winter carrots that are dug from February into June. Carrot rust fly larvae tunnel into roots here. The regional insect handbook recommends rotation, removing volunteer carrots, floating row covers and harvesting early, and notes that no insecticides are registered for home gardens.

Warm-winter areas (zones 9-11). In Florida, South Texas and the low desert, carrots grow from fall through spring and summer is off-season. Sow from late summer or early fall through late winter. Texas A&M plants South Texas carrots from July through February.

Common problems and how to fix them

• Forked, stubby or twisted roots: stones, clods, compaction, clay or crowding. Loosen the soil deeper, remove debris, thin on time, or move to a raised bed or a shorter carrot type.
• Cracked or split roots: heavy watering or rain after dry spells, or roots left in the ground too long. Water on a steady schedule and harvest at size.
• Bitter, coarse or pale roots: heat near maturity and moisture stress. Sow earlier in spring, switch to fall crops, and mulch and water through hot spells.
• Hairy roots with yellow, bunchy tops: aster yellows, which leafhoppers spread. Nothing cures infected plants, so pull them. Prevent it with row covers from emergence onward and by clearing weeds at the garden edge (Wisconsin).
• Tunnels and rusty-brown scars in the root: carrot fly or carrot rust fly maggots. Cover seedlings with row cover to keep egg-laying flies off, rotate the bed, and harvest promptly.
• Leaf spots that make the tops look scorched: Alternaria or Cercospora leaf blight, favored by long leaf wetness. Water in the morning, rotate on a 3-year cycle and clear old debris.
• Plants flowering in the first year: too much cold early in spring, or heat and drought stress. The root turns woody once the stalk forms, so pull those plants and sow later next spring.
• Green shoulders: sun on exposed root tops. Hill soil or mulch over them.

Harvest and storage

Pull carrots when the roots reach the size you want, usually 1 to 1 1/2 inches across at the shoulder (Texas A&M). Maryland picks fresh-eating carrots before they pass 1 inch. Expect harvest anywhere from 60 to over 100 days after sowing, depending on variety and season. Wisconsin gives 60-70 days, Clemson 65-75, Texas A&M 70-80, Utah State 70-100 and UF/IFAS up to 120 for Florida plantings. Storage carrots take about 100 days (Wisconsin). Loosen the soil with a digging fork before pulling so long roots don’t snap.

Cut the tops off right away, since leaves keep drawing moisture from the root. Store the roots as close to 32°F as you can, with high humidity. Clemson says topped carrots keep 4-6 months in ideal cold storage. Utah State is more conservative at 2-4 weeks in the cold and several months in moist sand in a cool cellar. Keep carrots away from apples and pears, which make them bitter (Utah State).

Utah State estimates about 1 pound of carrots per foot of row. Plan on 5-10 feet of row per person for fresh eating, plus 10-15 feet more if you want to store, freeze or can them.

A note on companions

Radishes are the one pairing with a clear practical reason. Sown in the carrot row, they mark it, break crust and are harvested before the carrots need the space. Most other carrot companion lists come from gardening tradition. Washington State University notes that mixed plantings may confuse pests such as carrot rust fly that find host plants by smell, but that there is little evidence that companion planting strategies actually control pests.