Carrots are a biennial vegetable in the family Apiaceae, related to parsnips, parsley, and celery. The modern cultivated carrot is classified by root size and shape. The most common carrot types include Amsterdam or Baby, Chantenay, Danvers or Danvers Half Long, Imperator, Nantes or Nantes Half Long, and Paris Market or Round.
While now cultivated primarily for its root, the carrot was originally grown, since at least 3,000 B.C., for its leaves and seeds. The oldest ancestors of the cultivated carrot are believed to have been native to Afghanistan. Carrots have been grown for their roots since at least 900 A.D. The modern orange carrot was developed in Holland during the late 17th century; for most of its history as a root vegetable since the Middle Ages, carrots were yellow, white, violet, and black, and today are available in these colors as well as orange, red, and pink, in many shades and variations in between, and in some cases with a core that is a different color than the skin.
Nantes types often perform and yield better than other carrots under challenging soil conditions, and are a good choice if planting carrots in previously uncultivated soil, for new gardeners, or those who have struggled before to produce good-quality carrot roots. Scarlet Nantes is a good classic choice, and Nelson (a hybrid) performs better than most carrots in clay and heavy soils. If your soils are shallow, rocky, or compacted, try Paris Market, which forms small rounded roots up to about 2 inches in diameter.
Carrots should generally be seeded directly, either broadcasted or planted in rows. GardenZeus recommends against purchasing carrot starts for transplant, as roots are easily damaged especially when very young. Some carrot root issues that result in poor harvest, such as multiple small forking roots rather than one larger taproot, develop very early within a carrot sprout's lifetime, often within the first few weeks after germination, or may be caused by transplanting. Some nurseries may happily sell you cell packs or transplants of lush-looking carrot seedlings, but these nearly always will result in a disappointing harvest of lesser-quality roots.
To form attractive, sizable roots, carrots need loose, uniform, evenly textured, friable, uncompacted soil without rocks or other obstructions to at least twice the expected depth of the carrot roots. Typically carrots will grow multiple forked, tough, or small roots in compacted and obstructed soils. Larger carrots, such as the Imperator types sold in supermarkets, need deep, loose soil, preferably to a depth of 30 inches or more, to form long single taproots. Carrots prefer soil that is fertile, with moderate but not too much nitrogen, and with moderate organic matter. Sandy loam is the ideal soil type for growing carrots.
Carrots prefer a soil pH of about 6.0 to 6.8, but will tolerate slightly alkaline soil and acidic soil with a pH as low as 5.5. Root development and harvest may be negatively affected outside of carrots’ preferred pH range.
Carrots produce the highest-quality, most-tender roots in soil temperatures of about 60 to 70° F. Carrots prefer shade during afternoons when temperatures are consistently above 80° F, and roots may lose color, become tough, and/or become bitter or unpleasant-tasting when soil temperatures are above 85° F. Carrots are often best planted in sunny southwestern or western exposures when grown from fall through spring, and in southeastern to southwestern exposures when grown from winter to summer.
If grown over winter, keep in mind that while carrots withstand short frosts to approximately 25° F, they are are biennials, and after a period of weeks of cool to cold temperatures, especially with a few periods of light frost, that are then followed by warmer days, carrots may respond as though winter has passed and spring has arrived by bolting, flowering, and setting seeds.
Carrots are relatively easy once you have the knack of growing them, but many gardeners have difficulty with them. See the GardenZeus carrot section "Planting Method/Tips" under the "Planting & Maintaining" tab for expert Darren Butler's summary of how to succeed the carrots.
The future shape of mature carrot roots is determined during the first several weeks of sprout growth. For this reason, GardenZeus recommends seeding carrots directly, and recommends transplanting of carrots only by biointensive and skilled gardeners. GardenZeus recommends never purchasing carrot starts for transplant in home gardens.
Carrots prefer uniformly moist but not wet soil; they are not a drought tolerant vegetable. Do not allow soil to dry between waterings. Overwatering or wet soil may result in poor root color, shallow rooting, and/or rotting or diseased roots. Underwatering or soil dryness between waterings may result in poor root formation or split roots.
Although carrot seeds germinate slowly at temperatures as low as 40° F, GardenZeus recommends a temperature range of 60 to 85° F for starting carrot seeds. Broadcast seeds directly outdoors or plant in rows. Carrot seeds must remain consistently moist to germinate well, and may require misting or watering with a gentle, fine spray two or more times per day. Carrots grow slowly at temperatures below 50° F.
GardenZeus expert Darren Butler believes that there is knack to growing carrots, like riding a bicycle. Until you "get it" with the carrot-growing knack, you may be surprised, disappointed, or frustrated with trying to grow carrots, especially when attempting to grow carrots in unsuitable conditions that you might not be aware of. After a few failed attempts, growing carrots may even come to seem impossible. Once you get the knack, growing carrots is relatively easy.
Darren Butler recommends this 8-part list for practicing the knack of growing large, tasty, single-rooted carrots. May you have many a happy ride on the carrot-growing bicycle:
1) Grow in loose, uncompacted, uniform soil without rocks or obstructions.
2) Grow in soil that is at least 2 to 3 times as deep as your expected carrot root length.
3) Grow in the ground rather than in containers if your soil is loose enough to do so. Carrots have fine roots that extend several feet deep, and so are not ideal for containers. If growing in containers, use deep containers (preferably 2 feet deep or deeper) or Paris Market "baby" and round varieties.
4) Seed directly in the ground or in containers unless you are a skilled biointensive gardener who knows how to properly prick out and transplant carrot starts. Many carrot root problems develop while seedlings are still tiny. It is easy to damage carrot roots in transplant, and as a result produce carrots with forked or poor root formation even if other growing conditions are ideal.
5) Grow during cool weather. Carrot roots form best in soil temperatures of 60 to 70° F. Harvest roots at whatever their size before weather warms consistently to 85° F or above.
6) Water your garden beds to flush weeds before planting carrot seeds, and apply a fine organic mulch after carrot tops are 1.5 inches tall to inhibit weeds. Use care with root disturbance, such as when thinning carrots during the first 5 weeks and with pulling weeds around carrots during the entire growing season. Generally it is best to cut weeds around carrots at soil level and discourage regrowth with mulch, rather than disturbing carrot roots by pulling out roots of nearby weeds.
7) Maintain even soil moisture. Carrots need fairly regular watering, and roots may fork, split, or become tough if soil dries out between waterings.
8) Use caution with applying nitrogen fertilizers. Carrots need moderate nitrogen to form large, tasty roots, but too much nitrogen may result in "furry" roots with many side shoots, or brittle roots that split easily.
Thin carrots when 2 inches tall to at least 1 inch apart. It’s best to cut thinnings at soil level with garden scissors or snips rather than pulling the young starts, as this may disturb the unthinned carrot roots, and encourage forked or misshapen roots. Thinning is critical during the first several weeks to avoid closely packed carrots that may grow crooked, misshapen, or entangled roots. Final spacing should be about 3 to 4 inches by 3 to 6 weeks after sprouts emerge.
5 to 21 days or longer to seed germination.
7 to 16 days from emergence of cotyledons until transplant of starts (GardenZeus recommends seeding carrots directly, and recommends transplanting carrots only for biointensive and skilled gardeners).
50 to 95 days from germination to root maturity.
Because we eat the roots of carrot plants, we prefer slow flowering (slow bolting), and are generally not concerned with pollination unless saving seeds.
Plant carrots with or near alliums such as leeks, onions, and chives. Carrots may benefit by being planted near nitrogen-fixing legumes such as peas and beans, especially in nitrogen-poor soils or when soils will not be supplemented with another form of nitrogen.
Radish seeds are traditionally planted at the same time with carrot seeds to mark rows as the radishes sprout and are harvested earlier than the slower carrots. GardenZeus recommends spacing radish plantings at least a few inches from carrots to avoid disturbing young carrot roots when harvesting the earlier radishes. Other traditional companions for carrots include leaf lettuce, rosemary, and sage.
Despite the common belief that carrots love tomatoes, which seems primarily based on the well-known book with that title, GardenZeus does not recommend planting carrots with tomatoes because they may actually stunt or diminish the growth of carrot roots.
GardenZeus recommends that you avoid planting carrots near other vegetables and herbs in the family Apiaceae, including celery, parsley, parsnips, dill, anise, coriander, and cilantro.
GardenZeus recommends growing your carrots organically in fertile soil with an active soil ecosystem to help support them in concentrating nutrients in their roots. Most soils with reasonable levels of organic matter and a pH of 6.0 to 6.8, should have sufficient nutrients for carrots with the exception of nitrogen.
Carrots generally need small to moderate amounts of supplemental nitrogen in most soils. GardenZeus recommends adding nitrogen in the form of diluted urea or a cup of chicken manure diluted in 4 gallons of water (half cup if fresh manure) and mixed thoroughly, applied as a soil drench once when carrots are 2 to 3 inches tall and about once per month throughout the growing season. Adding too much nitrogen may result in "furry" carrots with many fine roots, or in roots that split or break easily.
Use a quarter-inch fine mulch for small starts when they reach 2 to 3 inches in height; increase to half-an-inch or more of fine-to-medium mulch after plants are at least 4 to 5 inches tall.
GardenZeus does not recommend cutting back or pinching carrot leaves except for harvesting a minimal number of leaves for use as bitter greens in salads, soups, and other dishes.
From seed. GardenZeus recommends open-pollinated, untreated, organically grown seeds.
GardenZeus recommends a soil mix of at least 50% sand when growing carrots in containers. Potting soils with high proportions of organic matter tend to shrink and collapse over the course of a growing season as soil microbes and macro organisms like insects digest or decompose the organic matter, which results in falling soil levels and possibly insufficient soil depth for carrots to form full taproots. Nantes and Danvers are well-suited to growing in containers. Paris Market or round varieties are recommend for smaller pots of 12 inches or less depth.
Carrots tolerate warm-to-hot temperatures early in their life cycle, such as when germinating and in the first few weeks of growth, more so than they do after harvestable roots develop. Carrots may flower and go to seed after cold weather followed by a warming period.
A carrot root that appears wide and full at the soil surface may not necessarily have a long, single taproot, and it can be difficult to tell when roots are large enough for harvest based on how they look at ground level. It’s better to estimate harvest based upon the number of days that’s normal for your carrot variety from germination to harvest (check your seed packet). Usually about 50 days is sufficient for round or Paris Market (baby) and other round types, and generally 65 to 95 days are needed for other types depending upon factors like variety and your soil conditions. As harvest time approaches, you may need to harvest a single carrot here and there to check root size.
Harvest carrots anytime after the root is large enough to eat. If carrots stay too long in the ground, especially in warm-to-hot weather, roots may become tough or woody, or develop an unpleasant flavor. GardenZeus recommends that when possible, you leave tops on carrots after harvest to help them stay fresh longer. Harvest can be delayed and carrots kept longer in the ground during cool winter months.
Small, shallow, and forking roots: Many a gardener has spied colorful, wide shoulders at ground level on maturing carrots, and happily anticipated eating luscious carrot roots of several inches in length, only to discover at harvest that these root crowns disguise multiple tiny or tough unpalatable roots going sideways within the top inch or two of soil, or bunches of smaller roots wrapped around each other. These issues have many causes, including obstructed, compacted, or uneven soil; overcrowding; overly wet or waterlogged soils; overly alkaline or acidic soils; root disturbance during the first few weeks after planting or during transplanting; freezes or cold weather within the first several weeks after sprouting; root-knot nematodes; and soil fungi such as Pythium and Rhizoctonia.
Split roots are often caused by wet-dry soil cycles, uneven watering, or soil that dries out between waterings. Also may be caused by too much nitrogen.
Green root-tops are caused by exposure to sunlight. Cover roots with soil or mulch.
Furry roots or a vigorous root system with many small roots and no harvestable taproot: This is generally caused too much nitrogen. Carrots have extensive, fine root systems that often extend a few or several feet into soil, and they are effective at obtaining nitrogen from soil. Carrots may need only composted manure or minimal, occasional addition of nitrogen even in soils that are relatively low in nitrogen.
Poor or pale color in carrot roots may be caused by uneven soil moisture, soil that is too wet, and temperatures that are too hot or too cold during last few weeks before harvest.
Tough or woody roots, lack of sweetness, and/or unpleasant flavor are most often the result of temperatures above 85° F or roots staying in the ground too long, especially in warm-to-hot weather.
Bolting: Carrots may begin to flower and go to seed if they are exposed to a cold period followed by a warmer period or if left in the ground too long. There is nothing that can be done to reverse or stop bolting once it begins. Flowering carrots provide food for many beneficial insects, so this might not be a problem in the larger plans of an insect-friendly gardener, but it is a problem for your harvest, and will result in tough, woody, or unpalatable roots.
Slow growth, lack of vigor, small plants, production of few or small roots or leaves, yellowing leaves, dried-out or brown leaves: These common symptoms may result from soil pH that is too high or too low, compacted soil, alkaline soil, overwatering, underwatering, irregular watering, poor drainage, warm or heat weather, lack of soil nitrogen, other soil nutrient deficiencies, or a combination of these. May also be the result of hot weather, wind, or other environmental and abiotic factors. Burned leaf tips may also result from overfertilizing, sodic soils, or soluble salts in soils.
Carrot roots that are split but otherwise healthy at harvest can still be eaten, but they will not keep as well as unsplit carrots, so should be eaten as soon as possible after harvest.
Carrots are affected by various fungi and bacteria that cause softness, rotting, and other symptoms in roots. Carrot diseases are most common in wet soils, and they can be difficult to control or correct once carrots are infected. Bacterial Soft Rot often occurs in wet soils in your zone, especially during warm or hot weather, and is distinguished by a foul smell and lack of fungal growth.
Leaf discoloration in carrots is generally caused by various Leaf Blight fungi and bacteria, some of which harm carrot roots and some of which do not. Some leaf blights are seed-borne in carrots. Obtain a fresh supply of disease-free seeds.
The best solutions to disease problems with carrots are all preventative: avoid growing them repeatedly in the same place, encourage a thriving soil ecosystem, and otherwise meet carrots' cultural and environmental needs, especially with balanced watering.
Common pests of carrots include cutworms, aphids, flea beetles, crickets, rust flies, grasshoppers, leafhoppers, root-knot nematodes and other nematodes, ground squirrels, gophers, rabbits, and deer.
Weed management can be challenging with carrots. Some weeds, particularly nutsedges, are difficult to impossible to remove in a way that does not harm carrots. A carrot patch infested with nutsedge can be a gardening nightmare. Avoid planting carrots in areas with nutsedge, and watch carefully for first nutsedge pioneers and remove entirely including roots and soil around roots, as nutsedge notoriously leaves bulblets behind when the parent plants are removed.
For most gardeners, carrots should be grown from seeds. Carrots need loose, uniform, evenly textured, uncompacted soil without rocks or other obstructions for at least 2 to 3 times the expected length of the edible taproot. Loose, uniform soil to a depth of 30 inches is needed to produce the sizable Imperator carrots common at supermarkets. Applying the right amount of nitrogen is tricky with carrots; in most California soils, carrots will need some supplemental nitrogen, but too much nitrogen will result in furry, brittle, split, or easily damaged roots.
Once a carrot plant is at least 8 to 10 inches tall, a small proportion of its leaves may be harvested without harming root development for use as a bitter but highly nutritious green for salads, slaws, soups, as sauteed, and in many other dishes.
Queen Anne's Lace, considered by most in North America to be a weed, is the same species as the cultivated carrot and will readily cross-pollinate to produce variable or poor-quality carrot seeds in home gardens.
We all know what a carrot plant looks like—a stocky root with greens on top—but in a sustainable or ecofriendly vegetable garden, maybe not. Healthy, vigorous carrots in full flower can be a sight to behold, and bear little resemblance to carrots when harvested or purchased for eating. Often reaching a few to several feet in height and width in fertile soil, carrots in flower burst with lovely umbels of complex, delicate, beautiful blooms that are perfectly engineered by nature and coevolution as landing pads and feeding stations for beneficial insects. Leave a patch or two of your carrots (if saving seeds, avoid harvesting the most vigorous and healthy carrots) to mature over summer, and enjoy their striking blooms by late winter or the following spring.
Skilled biointensive gardeners often transplant carrots but timing is critical. Transplanting should occur without about 10 to 21 days after germination when the plants are small, less than 1.5 inches tall, and before roots touch the bottoms of their flats or growing containers. Transplanted carrots may need misting or gentle watering at least twice per day during the first week or two after transplant. Handle delicately when transplanting as damage to growing tips in tiny carrot starts will result in forked or misshapen roots at harvest time.
Carrots store exceptionally well; they can reasonably be expected to last for up to three to five months under ideal the conditions of 32° F and high humidity. To optimize the storage life of carrots, brush off all dirt, then wash and dry thoroughly. Unless you are using the carrots right away, remove the green tops by cutting through the green foliage, not carrot flesh, and place in a plastic bag. Leaving the green tops attached pulls moisture from roots to greens; bunched carrots with tops still attached can be expected to last only from 10 to 14 days, even in optimal storage conditions.
Humidity in refrigerators is too low for long term carrot storage. To store carrots in your refrigerator, do so in a humid produce drawer with humidity turned up to full, or with an open bowl of water, and/or in a cloth or plastic bag to reduce drying. Storing carrots in high humidity is essential to prevent loss of crispness and desiccation.
Placement of carrots in your refrigerator is also important. Segregate carrots in a separate drawer, away from fruits that produce ethylene gas: exposure to the ethylene gas given off by most fruits will cause carrots to have a bitter flavor within two weeks under normal storage conditions.
Carrots are a common ingredient found across a spectrum of cooking traditions and can be prepared in an endless variety of ways. In traditional French cuisine, carrots are one of the three ingredients in mirepoix, a combination of onions, celery and carrots that forms the basis for many sauces, stocks and soups. In American cooking, carrots are often used to flavor the drippings of roast chicken or beef. They can be braised in butter, roasted in olive oil, shredded for cakes and slaws, pulverized into juice, pickled for garnishes, sliced and baked for chips and dipped raw into hummus.
Carrots are one of the most nutritious vegetables that can be grown. They contain numerous vitamins, especially large amounts of vitamin A; beta-carotene; antioxident carotenoids; and many other vitamins, minerals, and nutrients.