How To Grow Carrots

The snap of a juicy carrot fresh from your own backyard is worth the bit of extra effort required to grow these vegetables successfully. "Carrots are one of the more finicky crops to get established," says Wesley Palmer, Southeastern territory sales representative for Johnny's Selected Seeds. "They take from one to three weeks to pop up, they don't germinate as easily as other crops such as radishes or beans, and they have a long growing season."

Another challenge is that carrots have a low germination rate, which is how many of the seeds you plant actually sprout. It's typically around 80 percent or lower, meaning 80 out of 100 seeds germinate. Because they're so fussy, it's smart to buy new carrot seeds annually to increase your odds of success. The seeds also are tiny, so some companies sell pelleted seed, which is coated in a thin layer of clay, to make uniform spacing when sowing easier, says Palmer. But with careful soil preparation and well-timed planting, you can reap a harvest of orange, yellow, white, or even purple carrots that add loads of color and crunch to your carrot raisin salad. Here's what you need to know to grow carrots.

Plant Attributes

Common Name	Carrot
Botanical Name	Daucus carota subsp. sativus
Family	Apiaceae
Plant Type	Biennial, annual, vegetable
Mature Size	1-2 ft. tall, 3-12 in. wide
Sun Exposure	Full
Soil Type	Moist, sandy, loamy, well-drained
Soil pH	Slightly acidic to neutral (6.0-7.0)
Hardiness Zones	4-11 (USDA)
Native Area	Europe

Carrot Care

To grow strong, straight carrots, the soil must be loose, deep, well-drained, and moist. Preparing the soil and removing obstacles like rocks and sticks is key. Thinning plants and relentlessly pulling up weeds also go a long way when it comes to growing carrots that are as beautiful as they are tasty. In most of the South, carrots are best planted in late summer or fall for a spring harvest.

Light

Carrots need full sun, that is, six or more hours of direct sunlight per day. They will tolerate partial sun but grow more slowly. You'll likely end up with undersized carrots.

Soil

Carrots grow best in loose, fertile, sandy loam, not red clay, says Palmer. But if you have soil that's like concrete, work on improving its texture by tilling in compost to a depth of 10 inches with a tiller or garden fork and rake. Remove all rocks, heavy clods, sticks, or any other impediments to roots, no matter how small. It's also a good idea to contact your local extension service (find yours here) for soil testing and other regional growing advice.

Water

Keep the soil evenly moist to germinate seeds and support rapid growth. Underwatering can result in tough, woody, bitter carrots. Once they begin to grow, water your carrots frequently and lightly, keeping the soil moderately moist.

Temperature And Humidity

Carrots germinate when soil temperatures are between 50 to 85 degrees, so you have two windows for planting: Spring and fall. Fall is actually the ideal time in the South because carrots planted in the spring may bolt, or go to seed, as a result of complex factors including the number of daylight hours and day-to-night temperature fluctuations, says Palmer.

In most of the South, you can sow seeds from March to April and from July to September. To beat the summer heat, gardeners in the Lower South often plant in February, while Coastal South gardeners plant from September to March. Sometimes when you plant in the fall, the seedlings pop up, then they don't do much until spring when they kick into high gear again; these carrots, which have overwintered, tend to be the sweetest, says Palmer.

Fertilizer

It's not usually necessary to fertilize carrots because they're not heavy feeders like tomatoes or corn. Amending the soil with compost at the beginning of the season is usually sufficient. However, it's okay to feed a water-soluble nitrogen fertilizer once during the season. But don't overdo it because too much nitrogen creates lots of top growth and not enough root growth, says Palmer.

Types Of Carrots

Great options for the South include Yaya, which is mild and crisp with a compact top; Mokum, which is a slender carrot that holds its sweetness even in hot weather; Romance, which is sweet with good disease resistance; and Bolero, which is reliable and stores for months, says Palmer. For a carrot that overwinters well and becomes sweeter after cold exposure, opt for Napoli. You can also experiment with multi-colored carrots or grow miniatures like 'Atlas' or 'Little Finger,' which can grow in shallower soil.

How To Grow Carrots From Seed

Although you can grow carrots in containers at least 12 inches deep, it's not recommended. The results will be lackluster. Instead, seed directly into the ground or in raised beds, says Palmer. Sprinkle the tiny seeds about an inch apart down a trench that is 1/4 to 1/2 inches deep. Rows can be placed 16 to 24 inches apart. Lightly cover and then sprinkle with water until moist. Continue to lightly water each day as you wait for the seeds to germinate in one to three weeks.

When To Thin Carrots

It feels a little unkind, but you've got to cut down on competition among the seedlings. Thin seedlings once their first leaves appear, which is when they're roughly an inch tall. "When you get the proper spacing early, they'll grow more vigorously," says Palmer. Use your fingers to pinch and pull up on a few baby plants at a time, creating 2 to 3 inches of space between plants. Yes, it's tedious but necessary. Also, make sure to keep the area weeded.

How To Harvest Carrots

Carrots mature 55 to 80 days after they break through the soil; keep your seed package and jot down the germination date, so you'll have an idea of when they'll be ready. Harvest when the crown of top of the carrot is slightly visible above the soil, says Palmer. Use a garden fork to loosen and lift each plant. If you're unsure they're ready, pull one up to check on progress. Rinse well, let dry, then store in a plastic perforated bag. Bonus: Don't toss the carrot tops, which be used to make pesto.

Overwintering

Carrots are biennial plants that easily withstand a Southern winter in most cases. If temperatures drop below 20 degrees Fahrenheit for an extended time, the tops die back to the ground. If you want your carrots to survive into the spring, a row cover should keep the plants warm enough to survive a long cold snap.

Even if the tops die back, the roots will survive. Many gardeners in cold climates swear by throwing a thick layer of straw over their carrots after a hard freeze. You can harvest the carrots all winter long and possibly into spring.

Common Pests & Plant Diseases

Carrots can be stunted by carrot-aster yellows, a disease spread by aster leafhoppers. The tops will begin to yellow, while roots can become hairy and branch. Dispose of any infected plants.

Parsley worms may feed on carrot tops, but home gardeners may want to let them be as they will develop into beautiful swallowtail butterflies. Slugs, on the other hand, should be picked off of plants.

The larvae of carrot rust flies can cause unsightly damage to roots in late spring or summer; place sticky traps near the soil if you notice eggs or larvae. Planting in fall can also avoid this problem.

Root-knot nematodes also damage roots and lead to hairy or branched carrots. The best prevention is crop rotation; don't plant carrots where other root vegetables have recently grown.

A fungal disease called Alternaria blight causes water-soaked brownish spots on leaves that later turn black and yellow and die. Practice crop rotation and look for disease-resistant varieties if you experience this problem. Home gardeners can use a fungicide containing chlorothalonil to try and manage the disease.

Common Problems

Much of what is happening occurs underground, so it's common to have a few surprises when you pull up your carrots. Here are some common issues gardeners face and how to fix them.

Tough, Woody Carrots

Carrots turn woody and develop a bitter flavor if left in the ground too long. Unless they will be overwintering, harvest your carrots as close to the maturity date as possible. If you'll be harvesting after winter, don't wait for the weather to turn hot. Once carrots bolt and produce seed, you won't want to eat them.

Bitter Carrots

Even young carrots can turn bitter from underwatering. Unlike many plants, carrots appreciate frequent, light watering over infrequent, deep watering. Keep an eye on soil moisture and water if you haven't had rain. At the same time, don't overwater, which can cause carrots to rot.

Stunted Or Deformed Roots

There are several factors that can cause stunted or deformed roots other than the diseases we discussed above. If you didn't loosen the soil deep enough, carrots will stop growing once they hit compacted soil. A small rock or clod of clay can also cause the root to fork. For future plantings, prepare 12 inches of soft, sandy, loamy, debris-free soil. Carrots will also be thin and underdeveloped if they aren't thinned enough. Unless you plan to harvest baby carrots, thin them to about 3 inches apart (blockier varieties may require even more space, so check your seed packet). Also, excess nitrogen can cause carrots to develop multiple roots instead of one long taproot. If you suspect fertilizer is the problem, don't use it again or wait until the plants are a few inches tall. With fresh compost, you may need to prepare your garden bed several weeks before sowing seeds so the compost can mature longer.