These knee-high, cool-season cabbage relatives are grown for their leaves, which can be steamed, stir-fried, sauted, or added to soups. Both are high in vitamins A and C and calcium. Hardy to 5F, these vegetables are winter staples. Kale grows 1430 in. high, and collards average 23 ft. high.
Curly-leafed kales (such as red-veined, purple-tinged 'Redbor' and blue-green 'Winterbor') form compact clusters of tightly curled leaves. 'Toscano' ('Lacinato') is a noncurly green kale also known as dinosaur kale and considered by many to be the best tasting. 'Red Russian' is a noncurly red kale whose leaves are gray-green with purple veins. Flowering kale is similar to flowering cabbage, with brightly colored, decorative foliage; it too is edible and is sometimes sold in markets under the name salad savoy. Collard greens come from large, smooth-leafed plants that do not form a head. Collard selections include 'Champion', 'Flash', 'Georgia', and 'Vates'.
Sow seeds in place, and thin to 1123 ft. apart; or set out transplants at the same spacing. Planted in early spring or late summer, collards and kale will yield edible leaves in fall, winter, and spring. Late-summer planting is preferable for the Lower, Coastal, and Tropical South; plant in either season for the Upper and Middle South.
Harvest leaves by removing them from the outside of clusters, or harvest entire plant. Light frost sweetens flavor. Plants suffer far fewer pest and disease problems than most other crops in the cabbage family.