Kale

Kale is a biennial leafy green in the cabbage family, grown as a cool-season vegetable. It is thought to have started in the eastern Mediterranean, and its name comes from the Latin word for cabbage. Plants usually reach 2 to 4 feet (61 to 122 cm) tall and wide, with large, thick leaves in green, blue-green and red-tinged shades. In late winter or spring, plants bolt and produce clusters of small yellow flowers that attract early bees.

Types. Red Russian and Siberian are technically different species that gardeners grow as kale, and Siberian is the most cold-hardy. Tuscan kale has narrow, puckered blue-gray leaves that stand upright and are often used for kale chips. Redbor has ruffled, deep maroon leaves, and Winterbor is slow to bolt in spring, which gives a longer harvest.

Sow kale seed outdoors in spring or fall, as North Carolina Extension notes it can be sown directly or planted as seedlings in either season. Plant seed about ¼ to ½ inch (0.6 to 1.3 cm) deep and space plants 12 to 18 inches (30 to 46 cm) apart, depending on the variety. Gardening experts suggest thinning when seedlings have 3 to 4 true leaves, and spacing rows about 2 feet (61 cm) apart. Gardening experts suggest sowing 3 to 4 seeds at each spot, thinning to one plant, and direct sowing from early spring until about 3 months before the expected fall frost.

Germination. Seed germinates with soil temperatures between 40 and 85 °F (4 to 29 °C). Gardening experts advise keeping soil above 75 °F (24 °C) until germination, if possible.

Transplants. Transplants should have 4 to 6 mature leaves and a well-developed root system, and should go out 4 to 5 weeks before the last frost-free date. Seeded kale may be planted at the same time.

Water. Gardening experts advise watering deeply and infrequently, about 1 to 2 inches (2.5 to 5 cm) per week, while keeping soil moisture even. Mulch helps hold moisture and reduce weeds. Gardening experts note kale responds well to regular watering.

Feeding. Get a soil test before planting and fertilize based on the results. Gardening experts suggest a nitrogen fertilizer about 4 weeks after transplanting or thinning.

Diseases and soil pests. Nematodes can be a big problem in sandy soils, and diseases may include leaf spot, black rot, mildew and bacterial leaf blight.

Insects. Aphids, cabbage worms and loopers, and flea beetles are common pests; flea beetles can reduce stands or kill seedlings. Gardening experts note kale has fewer pest problems than other brassicas, suggests row covers at planting, and recommends Bacillus thuringiensis (Bt) for cabbage worms and loopers.

Harvest leaves when they reach full size, taking the older leaves first so the young ones keep growing. For mature plants, pick leaves that are large but still tender from the bottom of the stem. Gardening experts say harvest can begin about 2 months after planting by clipping individual leaves. Frost improves the flavor.

Keep kale in a plastic container or bag lined with paper towels, in the produce drawer of the refrigerator, and wash it just before use. Gardening experts say it may keep up to a week or longer when stored well. Gardening experts say it can be stored 2 to 3 weeks at 32 °F (0 °C) and 95% humidity. To freeze, blanch clean leaves in boiling water for 2 to 3 minutes, cool them in ice water, drain, and freeze.