Carrots – February 2017 Plant of the Month

Whether you are a novice gardener or veteran with many seasons of experience, carrots are one of the most rewarding crops you can grow. Pulling the sweet tasting, brightly colored roots out of the ground is like unearthing buried treasure – a thrill no matter how many times it’s repeated. Fortunately, these nutritious veggies are usually easy to grow in most parts of the country. So put an X on your garden map to mark the spot where you’ll be unearthing garden gold at harvest time.

Varieties: Carrot varieties can be grouped into categories several ways -- based on their size and shape; when they ripen; and color. Also look for disease and crack resistant varieties.

  • Size and shape:
    • Long and tapered. Imperator types, the long, thin, tapered carrots you find in most supermarkets, have been bred for commercial production and mechanical harvesting. A better choice for most home gardeners are the sweet, crisp Nantes types, that are a little shorter (5-7 inches long) and a little stockier. These types do best in deep, relatively light, stone-free soil.
    • Medium and blunt. Chantenay and Danvers types are 4-6 inches long, with a chunky, blunt-tipped profile. These crisp, sweet carrots are a good choice for heavy soils.
    • Short and round. In stony or heavy soil, long carrots often develop forked roots. Choose short, stocky or round varieties such as 'Thumbelina', Paris Market’ or 'Little Finger' instead.
  • Maturity Date: Choose early, short-season varieties for late spring and summer eating. Main season varieties are a good choice for fall harvest and storage.
  • Color: Orange is the quintessential carrot color, and the majority of varieties are this hue. But you can also find carrot varieties in purple, red, and yellow – even white!

Site: Full sun is best. The main requirement for a good crop of carrots is loose, well-drained, moderately fertile soil, ideally without many stones. In stony or heavy soil, long, narrow carrots often develop forked roots; choose short, stocky or round varieties instead. Changing the growing location of carrots in the garden on a 3-year rotation will help to keep pest and disease problems at bay.

When to Plant: Make your first sowing of carrots about 2-3 weeks before the last frost date for your area. For a continued harvest make successive sowings every 2-3 weeks up until 10-12 weeks before your fall frost date. Carrots taste best when night temperatures stay below 60 degrees F; if they mature when it’s warmer than this they may taste bitter, so adjust your sowing dates to your climate and the days to maturity of the varieties you’re growing.

Planting: Direct seed carrots where they are to grow, as they don’t transplant well. Carrot seeds are tiny, so do your best to sow them thinly (1/2 inch apart). Mixing the seeds with some coarse sand or dried coffee grounds before planting makes it easier to achieve good spacing. Or you can buy pelleted seeds, which are seeds that have been covered with a biodegradable coating to make the individual seeds bigger and easier to handle. Scatter seeds in wide rows or plant in single rows 12 inches apart.

Plant seeds ½ inch deep. Carrot seedlings often have a hard time pushing through crusted soil. Covering seeds with material that won’t crust over, such as vermiculite, screened compost, or light potting mix, rather than garden soil will make it easier for seedlings to emerge. You can also mix some radish seeds in with your carrot seeds. The radishes germinate quickly, breaking up the soil crust in the process, and make it easier for the slower carrot seedlings to emerge. Then thin out the radish seedlings before they compete with the carrot seedlings.

Carrot seeds germinate slowly and unevenly over a period of 1-3 weeks. Keep the carrot bed lightly watered and consistently moist until germination is complete.

Thinning your carrot seedlings is essential for good growth. The best way to do this is to snip out extra plants at soil level with a pair of small, sharp scissors when the seedlings are an inch or two high. (Pulling out unwanted seedlings can disturb the plants you are keeping.) Check the seed packet for the desired spacing—2-4 inches, depending on the variety you’re growing.

Culture: Carrots do best with consistently moist, but well-drained soil. Mulching your carrot bed will help to conserve soil moisture and keep weeds down. Spread mulch when seedlings are a couple of inches high.

Troubleshooting:

  • Green shoulders: This occurs when the top of the carrot root pushes up out of the soil as it grows and is exposed to sunlight, causing the “shoulder” of the root to turn green and bitter tasting. To prevent this, hill up soil or pull mulch around the carrots to keep the tops of the roots in the dark.
  • Hole or tunnels in roots: Small, black holes in carrots are the work of wireworms. These yellow-brown, shiny, jointed worms are especially common in new garden areas that were previously covered with sod. To make a wireworm trap, stick a chunk of potato on a wooden skewer and bury it 2-4 inches deep. Set traps about 6 inches apart and check them couple of times a week. Either pick out any worms to reuse the trap or destroy the infested chunk of potato and replace with a fresh one. Carrot root maggots excavate tunnels on the surface of the roots. These maggots are the larvae of the carrot rust fly. Covering the carrot bed with a row cover will exclude the adult flies and keep them from laying eggs.
  • Cracked or forked roots: Carrots crack when the soil suddenly becomes very wet, either from rainfall or overwatering, as the roots are maturing. If your carrots are ripe and heavy rain is predicted after a dry spell, harvesting them could avoid cracking problems. Forked roots occur when the growing taproot encounters stones or clods of heavy soil. Short, stocky carrot varieties are the best choice in heavy or stony soils.
  • “Hairy” roots: If the surface of your carrots is covered with many fine roots, giving them a hairy look, too much nitrogen fertilizer may be the culprit. This can also happen if carrots are grown in waterlogged soil. Saturated soil when carrots are young can also cause roots to fork. Growing carrots in raised beds can help improve soil drainage and prevent problems from soggy soil.
  • Parsleyworms: These green, black and white or yellow caterpillars are the larval stage of black swallowtail butterflies. If you find any feeding on the leaves of your carrot plants, relocate them – don’t kill them! They feed on all members of the Carrot family, so transfer them to a wild Queen Anne’s lace plant or an extra parsley plant you’ve set aside for the purpose and wait for beautiful butterfly visitors to your garden.

Harvesting: You can begin harvesting carrots as soon as the roots reach a usable size, but they develop more flavor as they reach maturity. To harvest mature carrots, use the days to maturity on the seed packet as your guide. To get them out of the ground, make sure the soil is lightly moist. Loosen the soil carefully around your carrots with a garden fork, keeping the tool several inches away from the roots; then pull the carrots out by hand. This prevents bruised carrots that won’t store well.

For carrot recipes and ideas for classroom connections, check out Vermont Harvest of the Month’s Carrots

FUN FACTS

  • Looking at a carrot plant in your garden, with its root and leafy top, you may wonder where carrot seeds come from. Carrots are biennials, meaning they have a two year life cycle. If you leave a carrot plant in the ground over the winter (and your climate is warm enough for the plant to survive the winter), the top will produce flowers and eventually seeds in the second growing season. Exposure to cold weather is the signal to the plant that it is time to produce flowers. This is why, if you plant carrots too early in the spring, they may “think” that they’ve gone through a winter and begin to flower in the first growing season (called bolting) rather than producing large roots.
  • Cultivated carrots were first used as a food crop in central Asia in the 10th century and are thought to have been purple and yellow in color.
  • Carrots are the seventh most consumed fresh vegetable in the U.S.
  • In 2013, China produced a whopping 45.48% of the world’s carrots! The U.S. came in a distant fourth, at 3.47%.