Rutabaga

Rutabaga is a cool-season root crop in the cabbage family, and it is a cross between turnips and cabbage. It is also called swede, Swedish turnip, Russian turnip or yellow turnip. Botanically it is a biennial, but it is grown as an annual. Compared with a turnip, the root is larger, denser and sweeter, and it takes longer to mature. Plants usually reach about 1 to 2 feet (30 to 61 cm) tall, with a spread of about 8 to 12 inches (20 to 30 cm). Growers often choose it for a fall harvest, and it grows best in full sun.

Sow rutabaga seed in summer for a fall crop, because the plants develop slowly and do not handle summer heat well; summer sowing is the approach most often described for a fall crop. Sow the seed about ¼ to ½ inch (0.6 to 1.3 cm) deep. One seed supplier suggests 3/8 inch (1 cm) deep. Seeds are very small, so provide frequent, light watering to help them come up. Thin the seedlings to about 6 inches (15 cm) apart; another suggestion is 4 to 6 inches (10 to 15 cm) apart in rows about 18 inches (46 cm) apart.

Soil and sowing sites. Choose a site with well-drained soil where other Brassica crops have not grown in the past three years. Hard, crusty soil slows seedling emergence, so loosen the surface before sowing.

Soil and fertility. Rutabagas prefer fertile, well-drained soil rich in organic matter. A soil test is the best way to work out fertilizer needs. Side-dress with calcium nitrate about 3 to 4 weeks after planting, and avoid too much nitrogen, which may reduce root formation.

Watering. Plan on about 1 inch (2.5 cm) of water per week, or 1 to 1½ inches (2.5 to 3.8 cm) per week according to another source. Keep the soil moist but not soggy, and don’t let the leaves wilt between waterings. Uneven moisture can cause cracking, woody roots and bitter flavor.

Weeds and mulch. Rutabagas do not compete well with weeds. Cultivate shallowly, less than 2 inches (5 cm) deep, and add a light mulch of straw or grass clippings. Mulch also helps conserve soil moisture.

Clubroot. Clubroot is a soil-borne disease. If it appears, avoid planting rutabaga in that spot for at least 6 years.

Pests. Slugs, aphids, cutworms, looper caterpillars and flea beetles can chew the foliage, and a row cover helps protect the greens and keeps moths from laying eggs on the leaves. Aphids can be knocked off with a strong stream of water.

Rotation and leaf spot. Rotate planting locations from year to year. Avoid overhead watering and practice good sanitation to help control leaf spot.

Roots are usually harvested when they are about 3 to 5 inches (8 to 13 cm) across, because roots over 5 inches (13 cm) can turn tough. Estimates of time to maturity differ: one says 60 to 80 days from seeding, and another says 90 to 110 days from planting. Light frosts sweeten the flavor, so many growers wait for several light frosts before harvesting. Harvest ahead of a hard freeze, and avoid leaving roots in hot weather, which can make them pithy and strong-flavored. Leaves can be picked once plants are about 4 inches (10 cm) tall, as long as the top of the bulb is not damaged.

Before storing, trim the foliage to within 1 inch (2.5 cm) of the crown. Store them at 32 to 35 °F (0 to 2 °C) and 90 to 95% humidity for 2 to 4 months. Another estimate is about 35 °F (2 °C) and 95% humidity for 3 to 4 months, after washing the roots. Roots also keep well in plastic bags in the refrigerator or a cold root cellar.