By Dr. Leonard Perry
Carrots are loved by many, useful in many recipes, nutritious, and they store well. They’re also one of the top 10 most economically important vegetable crops in the world. Follow a few tips, and carrots are easy to grow in home gardens. For the best results, pay particular attention to good bed preparation, proper spacing, watering, and keeping up with weeding.
I grew up as many did with the advice to eat your carrots to improve your vision. While the Vitamin A from the beta-carotene (the name coming from carrots) in orange carrots does aid overall eye health, it won’t give you night vision if you eat lots of them, as some believe. However, eating an abundance of carrots can make your skin turn yellowish. Back off on the carrot intake for this to go away in a few weeks. Studies also have shown that carrots provide many health-promoting antioxidants.
In choosing a site to grow carrots, avoid planting them in the same bed where they or related family members—celery, dill, fennel, parsley, or parsnip—were grown in the last year or two. Crop rotation among plant families helps to maintain soil fertility, and lessens problems with pests and diseases.
One key to good growth and yields with carrots is proper soil—high in organic matter that is loose and well drained. Add an inch of good weed-free compost and work into the top half-foot of soil. Don’t work the soil when it is still wet in the spring, as this will form clods which don’t lead to straight roots. Dry, crumbly soil worked to a foot deep (you can just loosen it with a spading fork) is best. If you have a shallow soil or container, choose shorter varieties.
Don’t use fresh manure or excess nitrogen on carrots. This can cause roots to be forked, split, and rough or hairy. (Roots also can become fork-shaped from too much water.) I like to work in an organic vegetable fertilizer prior to planting. Carrots prefer moderate levels of nitrogen and low levels of phosphorus and potassium.
Check your soil acidity (pH) if you haven’t, or not for a couple years. Kits are available at garden stores and local Extension Service offices. The soil pH should be between 5.5 and 7.0. This is important for making nutrients available to the roots.
Carrots are grown from seeds, directly sown into garden or raised beds beginning in spring. They also can be sown into large fabric grow bags or containers. Germination takes about a week if soil temperatures are 70 to 75 degrees (F), up to three weeks if much cooler, with little to no germination below 45 degrees. A good time to sow is when you’re sowing pole beans or planting tomato transplants.
You’ll see many methods offered for sowing, but I like to sow (and have found subsequent maintenance easiest) when sown in rows five to seven inches apart. Plants should be two inches apart within rows. You can sow more densely and then thin seedlings, but thinning the small seedlings is rather tedious and can damage ones you want to leave. It will take longer at the beginning to carefully space and sow seeds one at a time, an inch or so apart and then thin as needed, but this results in much less thinning and work later.
When you do thin seedlings, young carrots can be tasty in salads. If too densely sown, cut those not desired with scissors to avoid damaging those that you’re leaving to grow on. If you want young carrots, sow successive crops every two to three weeks early in the summer.
Make sure to keep the seedbed watered daily or twice daily, if needed, until seeds are germinated and the seedlings are growing. Less water, but applied more frequently, is the key at this stage of growth. As the carrot plants are growing, water less often and with less water—this encourages longer roots. Then, toward the end of the season as roots are enlarging, water less often but more heavily when you do water—this encourages roots that taste and store better. If you aren’t able to provide ideal watering don’t worry, you should still get carrots, just not perhaps prizewinners at the fair.
Carrots will grow best with soil temperatures of 60 to 70 degrees Fahrenheit. The tops like to be warm, and the roots cool. You can achieve this, once they’re up and growing, with grass clippings or straw. If the soil is much above 70 degrees, roots will be small and taste bland, perhaps even bitter.
Mulching also helps to minimize weeds. Another key to successful carrot growing is to keep them weeded.
You can harvest carrots at most any stage of growth, depending on the size desired. Brightly colored carrots will have the best flavor and texture, the sugars then turning more to starches over time. Warm days and cool nights cause plants to make sugars and store them in the roots, so this results in sweeter carrots. Since the sugars are stored in the carrot “core,” thicker carrots with thicker cores often are the sweetest.
Harvest by gently pulling from the soil, if soils are loose. If tops break off, then loosen the soil first with a garden fork. Discard any that are split, injured, or rubbery.
Wash and scrub any carrots you’ll eat soon. Otherwise, cut tops off about an inch above the roots. Store carrots in damp sand or sawdust (95 percent humidity is ideal), as cool as possible, but above freezing. They easily should store for at least 6 months. If you don’t have a place for storage, they may be left in the ground, mulched, until the ground freezes.
There are dozens of carrot varieties you’ll find in catalogs and store seed racks, mostly orange but also in white (as White Satin), purple (as Purple Haze), red (as Atomic Red), yellow (as Yellowbunch), or a blend of these colors. These and the traditional orange carrots fall into one of five common types based on root shape.
Chantenay (as Royal Chantenay) are conical with broad shoulders (root tops) and rounded tips. Being sweet, they are good eaten fresh. Danvers (as Danvers Half Long) are cylindrical and thick. Having high water and low sugar content, these make good carrot juice. Nantes (as Purple Haze) also are cylindrical or “cigar-shaped”, but are sweet and crispy. Imperator (as Yellowbunch) are long and tapered, typical of those you find in plastic bags in grocery stores. Miniature or baby (as the stubby Atlas) are just that—they are not just long carrots that have been cut smaller, as some believe.
The word “carrot” comes from the Greek word (karoton) for horn, referring to the horn-like shape of the carrot taproot. To learn more about carrots, their history, and their many uses (even medicinally and as musical instruments), visit the World Carrot Museum online (www.carrotmuseum.co.uk
Dr. Leonard Perry is a horticulture professor at University of Vermont.