Know Before You Grow: Root Crops

Know Before You Grow: Root Crops
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Know Before You Grow: Root Crops

Root Crops Contain Numerous Vitamins and Nutrients

Root crops are popular with both commercial growers and home gardeners because they're versatile, delicious, and in many cases, perfect for canning or over-winter storage.

Beets, radishes, turnips, and carrots contain numerous vitamins and nutrients, offer a wide range of flavors and textures, can be enjoyed raw or cooked, and are wonderfully easy to grow.

Choosing Root Crop Varieties

When choosing which beets or radishes to grow there are several factors you will want to take into consideration. First of all, both come in a variety of interesting shapes and beautiful colors, so pick whatever appeals to your eye. Also, radishes offer varying degrees of heat and beets have flavors that range from earthy to sweet. Smaller beets are usually the best for canning and pickling, and many people enjoy the nutritious beet greens as well as the root itself. As far as choosing a type of carrot to plant, you will be deciding mostly by color and shape.

When to Start Root Crops

Direct sow your root crops in early spring or late summer. They're cool-weather crops, most preferring temperatures of around 70°F in order to germinate. All but carrots will germinate in a week to ten days. Carrots can take up to 3 weeks.

How to Start Root Crops

Direct sowing is preferable to transplanting because there is less root disturbance. Before sowing, cultivate deeply.

Beets: Soak the seeds in warm water for 24 hours before sowing—this will aid in germination. Early spring is the typical time to sow your beets, but in Zones 9 to 10 you can sow outdoors in the fall. Sow at a depth of 4 times the size of the seeds, planting successively at 3-week intervals for crops throughout the season. Site in full sun in a loose, rich, well-drained soil. Expect germination in 10 to 15 days and harvests within 50 to 60.

Radishes: Early spring is the typical time to sow your radishes, but in Zones 8 and warmer you can sow outdoors in the fall for a winter crop. Sow at a depth of 4 times the size of the seeds, planting successively at 2-week intervals until mid-spring and then again in late summer. Site in full sun in a loose, rich, sandy, moist, well-drained soil. Expect germination in 6 to 10 days.

Carrots: Early spring is the typical time to sow your carrots, but in warm climates you can sow outdoors in the fall for a fall crop. Sow at a ¼-inch depth, planting successively at 3-week intervals until early summer. Site in full sun in rich, loose, deeply worked and well-drained soil. Expect germination in 14 to 21 days.

Turnips: Sow in early spring after all danger of frost is past but while the ground is still cool. You can make successive sowings up to 5 weeks before temperatures are above 80°F, then again in late summer if you want a fall harvest. In Zones 8 and warmer you can also sow from early fall through spring for continuous crops over the winter. Sow at a depth of 4 times the size of the seeds. Site in full sun in fertile, moist, well-drained soil. Expect germination in 8 to 10 days.

Special Considerations

  • Apply mulch or soil around the tops of the roots to eliminate green shoulders.
  • Thinning out seedlings is particularly important when dealing with beets, as each beet “seed” is actually a fruit that harbors several seeds. Remove the smaller, weaker seedlings and allow the stronger ones to grow. The ones that have been removed can then be used as greens.
  • Crowding and insufficient water can cause radishes to bolt or fail to form a bulb.
  • Carrots—young seedlings are weak and slow growing, so if a heavy rain occurs after your seeds have been sown and the surface of the soil becomes packed, you may not have any seedlings emerge.
  • Keeping weeds under control is especially important during the first few weeks after planting. Be careful to only do shallow cultivation, however, as digging too deeply can injure tender roots.

Growing Tips: Beets, Radishes, Turnips, Carrots

  • Most root crops prefer loose soils and cool temperatures.


  • Fertilize prior to planting your beets and again when the plants are 3 to 4 inches tall. Keep the plants well watered.
  • You can harvest your beets at any time during their growth cycle, but they are typically most tender after 40 to 50 days, when they're between 1½ to 2 inches in diameter. The greens are best if picked when they're about 4 to 6 inches tall.
  • Leave at least an inch of foliage on the beet root when you harvest. This will prevent bleeding during cooking.
  • Beet roots and greens will keep in your garden for 2 to 3 weeks after they have matured, and once harvested, the roots will keep for up to a month (store near freezing, with high humidity to prevent wilting).


  • Use a liquid fertilizer prior to planting your radishes and then again every 2 weeks. Keep the plants well watered.
  • Radish leaves can also be harvested. They're best when young, about ½ to 1½ inches across. You can cook them or add them fresh to a mixed salad.


  • Fertilize prior to sowing your Turnips and again when the plants are about 4 inches tall.
  • Turnip greens are also quite popular and are best harvested when young and tender. The roots themselves should be harvested when they're about 2 inches across.


  • Carrots are typically sown using two different methods. The first is to plant in single-file rows. The other way is to scatter the seeds in areas up to 12 inches wide. Both methods work quite well, but the second one provides higher yields.
  • Since carrots are slow to germinate (keep soil moist throughout germination), you can mix faster-germinating veggies such as radishes or lettuce with the carrot seeds. This not only marks the area for watering and weeding but these other seeds can help break up any crusting on the soil surface, making growth easier for your carrots. You'll harvest these other veggies before they have a chance to crowd the carrots.
  • Apply a 1- to 3-inch layer of dried grass clippings, well-rotted compost, or other organic mulch around the base of your carrots once they've emerged and are growing well. This will conserve moisture, regulate soil temperatures, reduce weeds, and help prevent the tops of the roots from turning green or purple. These discolored areas will have a slightly bitter taste.
  • Carrots are harvested from baby size to full grown, and their leafy tops are used to flavor soups and other dishes.
  • Foliage growth in carrots can be misleading, so don't use that as an indication of root size. Loosen the soil around the top of the carrot, and if the roots are finger-sized or larger, they're ready to eat.
  • Store your carrots at 32 to 40°F, or in fall and winter, just leave them in the garden until you want them.

Pests and Problems to Watch For

  • The most common problem people face when growing root crops is failing to thin the plants properly. Sufficient space is essential for healthy crops.
  • Root maggots can tunnel into radishes. If this has been a problem in the past, apply an appropriate soil insecticide before planting.
  • A lot of moisture after a dry spell can cause mature roots to burst and split. Try to maintain an even level of moisture.
  • Carrots—forking (forked or deformed roots) can result from stones, deep and close cultivation, planting in a soil that's poorly prepared, or the attack of root-knot nematodes. These parasites exist in the soil in areas with hot climates or short winters. They infect the roots and create root-knot galls that drain the plant's nutrients. Young plants that are infected may die, while mature plants usually have a decreased yield. There are several means of control, including crop rotation and treatment of the soil with appropriate pesticides. Contact your County Extension office for removal or prevention methods.
  • Carrots—seeding too thickly and not thinning the seedlings adequately will result in twisting and intertwining of the roots.

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