Early Nantes Napoli is a long slender carrot. Photo by NGB.
Each year the National Garden Bureau selects several different types of plants to be designated as the “Year of” plants. This year’s selection for the vegetable of the year is carrots (Daucus carota subsp. sativus). Carrots are easy to grow, are very adaptable to most garden soils and locations, come in a wide variety of types and colors and are nutritious as well.
Modern day carrots have come a long way from the darkly colored, pungent native carrots from the region of Afghanistan. The Dutch actually were responsible for breeding the more typical orange carrots back in the 16th Century, that we are used to eating today. But many vegetable breeders and heirloom vegetable enthusiasts have been working to expand the carrot color pallet to include yellow, white, purple and some that are nearly black. While beta carotene has long been known to be one of the most abundant nutrients in carrots, some of these other types of colored carrots have varying amounts of this important provitamin as well as anti-oxidants.
Carrots are easy to grow in most gardens providing they will have full sun exposure for at least six hours each day, the soil is relatively free of rocks or stones, you can provide water during dry periods and you can keep up with the weeds. Since we eat the roots of carrots, which are really storage organs for the excess carbohydrates and other compounds that the carrot plant produces, they have to be grown in a sunny enough location to produce lots of carbohydrates through the process of photosynthesis. If a garden is too shady, the carrots will not grow very well or produce very large roots. Rocky, stony or even compacted soils will interfere with the proper development of the carrot roots, causing them to branch out instead of forming a nice straight root. Carrots need a consistent supply of water to grow well. In fact, some carrot roots contain more water, pound per pound, than a watermelon! Weeds will compete with the carrots for light, water and nutrients as well as be a potential carrier of diseases or harbor insects so it is important to keep the weeds down around your carrot plants as well as around other vegetables.
There are dozens of different varieties of carrots available that come in a variety of shapes, mostly varying in how long they typically grow and how wide at the shoulders they develop. Loose, deep, sandy or peat type soils are more suitable for the longer growing types of carrots like Imperator or Nantes. Plant varieties with shorter-growing roots in heavier soils like Chantenay or Danvers. Globe, mini or baby carrots work well in more compacted soils or for a shorter maturity date. Carrots can also be grown in containers, just be sure to use a deep enough container to allow for good root growth and keep the potting soil well-watered to avoid water stress.
|Canberra is a Chantenay type carrot. Photo by NGB.||Atlas carrots are a type of globe shaped carrots. Photo by NGB.|
Probably the most difficult aspect of growing carrots successfully is getting a good stand of seedlings established. The seed is quite small which can make it difficult to plant. If you try to plant it on a windy day, you may lose more seed than you get in the planting furrow. Some seed companies produce pelleted seed which makes the seed easier to see, adds some weight to the seed and makes proper seed spacing easier. Generally the seed should be spaced about ½” to 1” apart but extra seedlings can be thinned out after they emerge.
Proper planting depth is also important, particularly in our heavier soils. Generally the seed should only be covered with about a ¼” of soil. If your soil is particularly clumpy or hard when you plant, consider using some inexpensive potting soil to cover the seed instead of garden soil. This will probably provide a better germination environment for the seed than trying to grow amongst comparatively boulder-sized clods of soil. Try to keep the soil moist until the seedlings emerge. However, a heavy rain can wash out the seed or cause the soil to crust-over which can inhibit seedling emergence.
Carrot seedlings are quite small and delicate when they first emerge. The first thing you will notice are the two thin cotyledons or seed leaves. Once those have developed the true, more fern-like leaves start to develop but because the plants are so small, it might take a couple weeks before the plants are large enough to be noticeable. Once the seedlings have several true leaves, it’s time to do your first weeding close to the carrot seedlings. This is also a good time to thin out any extra carrot seedlings so that ultimately each carrot plant is spaced out about 2 to 3” apart. If carrots are allowed to grow too thickly in the row, they will compete with each other for space, light and nutrients so that none of them really produces good-sized roots.
Some gardeners prefer to plant carrots in rows, about 8 to 12” wide, or planting multiple rows spaced about 6 to 8” apart. It is still important to thin out the seedlings but in this case this so they are spaced about 4 to 6” apart. Wide row or multiple row planting saves garden space, making more intensive use of a smaller garden plot or raised bed. You can allow your seedlings to grow a bit closer together if you plan on harvesting every other one, as young carrots, once they begin to form edible-sized roots. Those small, succulent carrots can be a real treat!
Care & Pest Management
It is important to keep up with the weeding so that the carrot plants are ahead of the weeds. But you also have to be careful when using equipment, like a rototiller, that might spread tilled soil over small seedlings. It is probably best to weed by hand or use a hoe that you can control more carefully to avoid damaging nearby carrot plants. Once carrots get a bit larger, about 6 to 8” tall, a little mounding of soil over the tops of the roots will help prevent the shoulders from turning green which can impart a bitter flavor to the tops of the carrot roots or shoulders.
Carrots generally do not have a lot of disease or pest problems in the garden. Occasionally blister beetles may become a problem. These tan-striped or black beetles feed on the foliage of carrots and other vegetables. Aster yellows, a disease caused by a mycoplasma, will cause yellowing of the foliage followed by an excessive amount of shoots developing at the top of the carrot. The roots will develop a proliferation of fine roots and lose quality. Later the leaves take on a bronzed appearance. If you see carrot plants developing these symptoms it is a good idea to remove them from the garden. The disease is spread by leaf hoppers. Probably the other most common problem is growth cracks. This is a physiological problem caused by inconsistent water availability to the plants. Cracks will develop along the length of the carrot which may lead to infection by soil borne pathogens which may cause rot inside the carrot root. Try to maintain consistent moisture availability to the carrots throughout the growing season.
|Striped blister beetle on carrot.||Aster yellows can cause reddish discoloration of carrot leaves.|
Most carrot varieties need about 60 to 75 days to reach maturity but you can start harvesting before that if you wish. Harvesting can continue into the fall and even into the early winter if you heavily mulch over the carrots to keep them and the ground from freezing. Cooler fall temperatures actually help sweeten the carrots as it fosters the conversion of starches, stored in the roots, to sugars. Carrots are often difficult to just pull from the ground. Usually you will need to use a spading fork or shovel to loosen the soil around the carrots to allow them to be removed from the soil. Try to avoid piercing or slicing the carrots off during the digging process, particularly if you plan to put them into storage.
Once harvested, carrots can be cleaned, tops removed, placed in perforated plastic bags and stored in a refrigerator for weeks. Another option is to cut the tops off, just above the top of the root, then stand them up in a bucket or tub and cover them with slightly moistened potting soil or peat moss. Place them in a cool location but one that does not freeze. This way you can pull carrots as you want them, recovering any exposed roots so they do not dry out. If the potting soil or peat moss gets too dry, sprinkle with some water.
For more information about carrots, visit the National Garden Bureau website.