Carrots may not be glamorous, yet they are truly one of the delights of the home vegetable garden.
They come in a stunning variety of shapes, sizes and colors. Freshly harvested, they are so much sweeter, crisper and juicier than their grocery store counterparts. Some gardeners find them fussy to grow, with their primary requirement of very deeply-worked, rich soil, but they’re worthwhile and, once you get the knack, no more difficult than other crops.
Carrots originated in western Asia, which is still the center of diversity for the wild form. The original color was mainly white, red or purple. Orange carrots, in fact, are a relatively recent development. They were originally a product of Dutch breeding and are believed to have existed no earlier than the 1600s.
Carrots were originally appreciated more for their aromatic foliage, which resembles parsley, than for their roots. Over centuries of selection, however, the roots became milder and less woody — in a word, more palatable. It is believed that the crop was grown in ancient Egypt, and certainly later, by the Greeks and Romans. The earliest mention of them occurs in a work by Theophrastus, who, in the third century B.C., indicated that the best carrots were produced around Sparta. They are also mentioned by the elder Pliny. But the record is less certain than with other crops, because carrots were often confused with their close relative, parsnips — it’s difficult to know which vegetable is actually being discussed in ancient texts. The plant, and especially its seeds, were highly valued in ancient herbal medicine. Among other virtues, it was believed that the seeds had the ability to neutralize poisons.
To grow great carrots you need to start with your soil. Carrots are sweeter and milder when grown in a neutral soil pH, so start with a soil test and add lime if necessary. The ideal soil pH should be around 6.5, or a bit higher. Once you’ve got that right, turn your attention to soil nutrients. Your soil test will offer specific recommendations, but the bottom line is this: carrots need a good, rich, mellow garden soil, well-worked, with plenty of organic matter. It also goes without saying that they need excellent drainage and full sun.
Starting with ordinary garden soil, work up your carrot bed or row. Work your soil into a very fine texture — carrots don’t thrive in rough, rocky, or cloddy soil, or rather, they won’t give smooth, straight roots when grown on such soils. Instead, the roots will branch, fork, and generally detour around subterranean obstacles. You can still eat them, yes, but preparing them becomes a serious chore.
Add mature compost, at least one-half inch, and work it in. But never add fresh manure, as too much nitrogen makes your carrot roots “hairy” (meaning the main root sends out lots of root hairs all along its length to feed on that nitrogen — not pleasant when you get those roots into the kitchen.) If you must use fresh manure it’s OK, provided you apply it several weeks ahead of planting. The hiatus gives soil microorganisms a chance to work on all those nutrients, refining them to the mellow levels that carrots require. If you plan to grow long-rooted cultivars, like ‘Saint Valery,’ you’ll need to work the soil deeply. The well-worked soil should extend at least a couple of inches deeper than the length of the roots you expect to harvest, so for full-sized varieties you need to work the soil at least 14 inches deep. The soil should be fine and crumbly for the entire depth and free of any but the smallest stones.
If this is sounding less and less like your garden, don’t give up hope — you can still grow great carrots. You just need to grow shorter-rooted cultivars, like ‘Oxheart,’ and ‘Chantenay Red Core.’ Such cultivars still have the same requirements as to their soil, but being shorter, they don’t need soft, friable soil as deep. There are even round cultivars, like ‘Tonda di Parigi,’ that can grow in very shallow soil, just 3-4 inches deep.
Time your planting to take advantage of cooler weather — carrots won’t sprout well in too-warm soils, and roots that mature in the heat of summer can be coarse-flavored. A soil temperature of about 55-60 degrees Fahrenheit is ideal. Such a temperature is likely to occur a few weeks before, to a few weeks after, the last frost date of spring. Succession planting yields a new mini-crop of carrots every couple of weeks, so plant a small row every two weeks until hot weather arrives, probably by early June. At that point, the soil is apt to be too hot and dry to allow good germination. But start again in late summer, waiting for the heat to break in late August or so. Your storage crop is the final sowing of the season; plant about four to six weeks ahead of the first autumn frost date. (In cool-summer areas, like many coastal regions and higher elevations, there is no need for a midsummer pause.)
Plant your seeds in a shallow furrow, or sprinkle them on the surface of the bed. Carrot seeds are tiny, so they shouldn’t be covered very deeply — one-fourth inch is about right. They germinate slowly, often requiring up to two weeks. Every weed in your garden germinates faster than that, so old-time gardening books recommended “marking” the rows by planting radishes along with the carrot seeds. The radish seeds sprout in just a few days, which shows the location of the row, and the radishes are harvested at about a month, vacating the space at just about the time the carrots begin to get large enough to need it. However you plant, you’ll need to control the weeds, and this for most of us is the hardest part. It’s critical to remove tiny weed seedlings as soon as they appear; to facilitate this, rows are probably easier to work with than beds, unless weed pressure is very light. Carrot seed is also vulnerable to drying, which can be fatal. Early spring plantings may get enough moisture from rain or dew, but later ones will need careful irrigation. An easy alternative is to cover the beds with an old blanket, carpeting, or burlap sacks to shade the soil and hold moisture in. Obviously, these must be removed as soon as sprouts appear.
Spacing the plants actually isn’t terribly critical, and varies from gardener to gardener. The truth is, in very good carrot soil, carrots will grow to crisp, juicy maturity only a couple of inches away from their nearest neighbors. However, weeding can be difficult at such close spacing; so for many it works better to space the plants 2-3 inches apart in rows far enough apart to accommodate a hoe.
Unlike weeding, thinning is best approached gradually, because if allowed to get to some size, the thinnings can be part of the harvest — these true “baby carrots” are the sweetest of all, and the greens are edible too. The only rule is to thin the young plants whenever the developing roots begin to touch one another.
Carrots respond well to mulching, once the plants are large enough to make this practicable. A good mulch holds moisture and discourages weeds. Many materials will work, including hay, straw and sawdust, but if you’ve got enough compost, it will feed your carrots as well.
Pests and diseases are relatively few. Root-knot nematode and aster yellows are the main ones. Both are largely eliminated by crop rotation (planting your carrots into a different spot each year, and not returning to the original site for at least four years), and by good garden cleanup (removing spent and especially diseased plant material). Leaf-hoppers do spread diseases around, including carrot maladies, and should be controlled. Row cover excludes them, and applications of diatomaceous earth, neem oil or pyrethrum are effective organic controls. Most gardeners will seldom have serious pest or disease issues with carrots.
If all the potential pitfalls have been avoided, the main carrot harvest begins about 70 days after sowing. In truly optimal carrot soil it may be possible to grasp the tops of the plants and pull the roots. However, in most of the real world, that only works with the stubby, short-rooted types. Longer-rooted varieties will need a little encouragement, in the form of a digging fork or spade carefully inserted underneath the plants. A slight effort should pry the roots loose. Once harvested, cut the tops promptly to within 1-2 inches of the root itself. Carrots with tops intact may look wholesome and natural, but the leaves draw moisture from the roots, causing them to lose their crisp, juicy texture.
Storing Your Crop
Carrots are designed by nature to overwinter as a dormant root, then emerge the following spring to flower and mature their seed. This bit of natural history tells the alert gardener what they need to know to store the carrot crop: carrots need to be stored in cool, humid conditions. Any location that meets these simple requirements will serve. Naturally, the fridge’s crisper drawer is optimal, but a winter’s supply of carrots might need more space. A root cellar is the low-tech holy grail of carrot storage, but if you haven’t got one, there are other options. Your carrots would be happy in a box, bin or tub in a corner of an unheated basement, preferably surrounded by damp sand to keep them crisp. In milder climates, Zone 6 and above, the crunchy morsels can be stored right were they grew: simply mulch the bed or row heavily, and venture outside occasionally to “harvest” a short-term supply.
To save seed, your first-year carrots must overwinter one way or another. If overwintered indoors, they are replanted in early spring, as soon as the ground can be worked. There they revive, first sending up fresh green growth and eventually flower spikes. Each spike becomes a generous umbel containing scores of tiny white flowers, each of which yields a seed. The average home gardener will garner plenty of seed by gently plucking them from the drying flower heads. Larger quantities can be had by picking entire umbels and threshing and winnowing.
Pollination is a concern. Carrots are mainly bee-pollinated, so a healthy bee population is a necessity. Also, the bees carry the pollen up to one-half mile. To keep a pure strain, only one cultivar at a time should be grown for seed. Unfortunately, in many areas there is already a wild form of carrot, popularly called Queen Anne’s lace, which does not make a large succulent root. If chance pollination with this should occur when you’re growing your seed crop, the offspring won’t be true to type and will probably be inferior, although they would still be edible.
So give carrots the chance they deserve this season. A little bit of care rewards you with plenty of healthful good eating.
Randel A. Agrella has overseen rare seed production at Baker Creek since 2005. He writes and lectures extensively, and owns and operates AbundantAcres.net, which has grown and shipped strictly heirloom, chemical-free veggie starts and plants since 2004. He has recently relocated to Maine, and you can follow the development of his organic micro-farm, Parsnippity Farm, on Facebook.