Gardening With Root Crops

The neat rows of foliage swaying in the cool breeze hides the tasty treats developing under the soil's surface. Root vegetables are a staple in many kitchens, from crunchy raw additions to a salad or relish tray, to soft mounds of mashed deliciousness, smothered in butter. Gardening with root crops is relatively easy and allows you to produce healthy, homegrown vegetables through the fall and winter.

Beets (Beta vulgaris) are generally grown as annuals in the garden, although they are biennials. The firm white, yellow, orange, pink, red or striped fruits are hardy in U.S. Department of Agriculture plant hardiness zones 3 through 10. A cool-weather plant, beets are grown in winter in USDA zones 8b through 10, and through the spring and summer in USDA zones 3 through 8a. In addition to the roots, beet tops are a nutritious addition to the dinner table. A few young leaves trimmed from each plant provides greens for dinner without harming the development of the root. There is also a variety of beets grown solely for their leaves, known as chard or Swiss chard.

Biennials are plants that set seed in their second season of growth. In cold climates, the roots must be protected from freezing or lifted and stored in a cool, humid environment until spring. After replanting, they flower and produce seeds.

Generally, seeds from hybrid varieties do not grow true to the parent plant. Heirloom seeds, however, are collected in the second season to continue cultivating the old-fashioned cultivars.

The easy-to-grow carrot (Daucus carota var. sativus) is also a biennial but usually grown as an annual in USDA zones 3 through 9. Like the beet, carrots can overwinter when protected from freezing, although a touch of frost enhances the flavor of the root. There are many cultivars, ranging from those that mature when the roots are still small, to stubby roots that thrive in heavy soils, to those with long, thin tender roots. Carrots, especially heirloom varieties, are found in many colors, from white to orange to black.

The pungent aroma of the onion (Allium cepa) is not released into the air until you cut through the bulb's cell walls. Onions are grown from seeds or sets, which are actually small onion bulbs. Hardy in USDA zones 3 through 10, onions can overwinter in the ground if protected from freezing. Otherwise, they are either harvested for the kitchen or lifted and replanted in spring so they can flower and produce seeds.

There are two main types of onions, long-day and short-day. Long-day onions produce bulbs when the days are 14 to 15 hours long. These varieties are planted in spring in USDA zones 3 through 5. Short-day onions produce bulbs when daylight is from 12 to 13 hours long. They are planted in fall in USDA zones 8 through 10. Gardeners in USDA zones 6 through 7 can plant long-day onions in spring and then short-day onions in fall, to produce two crops every year.

Parsnips (Pastinaca sativa) are closely related to carrots. Before the Europeans brought the potato over from the Americas, the parsnip was the main starchy food. The long, white roots are slow-growing, thriving in USDA zones 3 through 9. A hardy root vegetable, the sweetest parsnips are planted in fall and harvested in early spring.

The parsnip has spread outside of the garden, becoming an invasive plant. In Ohio, it is officially listed as an invasive, noxious weed. To prevent parsnips from escaping the garden, harvest the roots every year; the plant flowers in its second season of growth.

Most potatoes (Solanum tuberosum) are grown from seed potatoes, although the plants can produce flowers and small green fruits with seeds. The tubers are actually rhizomes. Potatoes are grown as cool-season annuals, planted two to three weeks before the last frost date.

Some gardeners grow potatoes in towers of old tires, filling the tires with straw, compost or potting soil as the vines grow, so only a few inches show above the planting medium. New potatoes and roots grow along the buried vines. When the tower reaches four or five tires high, the gardener allows the vines to grow and spill over the edges. When the vines die back, the potatoes are easily harvested by removing the tires, one-by-one, and sifting through the medium to find the tubers.

All parts of the potato plant except mature tubers are poisonous. A potato with a green-tinged skin may be peeled but if the flesh below the peel is green, do not eat the tuber. Put it in the trash, where it is out of reach of children and pets.

The fast-growing red and white bulbs of the radish (Raphanus sativus), sliced and eaten raw, add a spicy, peppery flavor to a meal. The salad radishes are annuals, however, the daikon radishes are biennials, hardy in USDA zones 3 through 10. Salad radishes may be planted from spring through fall and in mild winter regions, as a winter crop. Hot weather can make radishes tough and too spicy, however. Daikon radishes are generally planted in spring for a summer crop or in fall as a winter crop. Both types are frost-tolerant and become sweeter in cold weather.

The old-fashioned rutabaga (Brassica napus) has been cultivated since the Middle Ages in Europe. Believed to be a hybrid of a turnip (Brassica rapa var. rapifera) and kale (Brassica oleracea var. acephala), the yellow-orange or white root vegetable can be baked, boiled, mashed, fried or eaten raw. Rutabagas are grown in USDA hardiness zones 3 through 10 and, like other cool weather root vegetables, are planted in fall and grown in winter in mild winter climates. It is also a biennial.

The sweet, crunchy turnip, a biennial, grows in USDA hardiness zones 3 through 10. Frosts and moderate freezes make the root sweeter, converting the starches to sugars. It is grown in winter in USDA zones 8 and above, with the seeds being planted in the garden from September to November. In cooler climates, it's planted in early spring for a summer crop. Both the roots and tender young leaves are a nutritious and tasty addition to the dinner table.

Root vegetables need full sun and a loose, well-drained, slightly acidic soil, with a pH of 6.0 to 6.8. Dig in compost to add nutrients and organic matter to the garden bed, then plant the seeds or sets. In general, root vegetables are cool-weather plants. The roots should be harvested while relatively small, 1 to 2 1/2 inches in diameter, depending on the species, to ensure that they are tender and not fibrous.

Protect your skin, eyes and lungs when working in the garden, while digging, planting and fertilizing. Use sunscreen, even in winter, and wear shoes, long pants, long sleeves, gloves, safety glasses and a dust mask.

Water when the soil is dry to the touch, adding 1 inch of water to the garden weekly. One inch of water is equal to 6 gallons of water applied to 1 square yard of soil. Root vegetables need regular water or they become tough and in some cases, pungent.

Mix a slow-release fertilizer, such as a 5-10-10, at a rate of 2 to 3 pounds per 100 square feet, into the top 2 to 3 inches of soil before planting the seeds. Always water thoroughly after fertilizing to avoid burning the seeds or emerging seedlings and their delicate roots. Repeat fertilizing in three months, or according to the manufacturer's directions.

Because root vegetables are grown in early spring and during winter, many pests are still riding out the cold weather. By cleaning the garden before planting, removing the summer garden's debris and replacing the old mulch, you can disrupt the pests' life cycle, reducing the number of ravenous pests. Hand-pick snails and slugs, which love cool, damp weather, or put out shallow pans filled with beer or fermenting yeast to trap the slimy pests.