Collards and kale are best thought of as loose-leaf cabbages. They are the closest of our modern garden brassicas to the original wild cabbage from which all were developed. They are easier to grow than cabbage, more nutritious than broccoli, and, in the opinion of many, better-tasting than even the best Brussels sprouts. Collards are grown primarily in the South, and kale in the North.
Both are normally fall crops, though early spring sowings will produce until hot weather sets in. Seed in midsummer and thin to eighteen inches apart so the plants can grow to full size. Pests and diseases are technically the same as for the other members of the cabbage family, but few seem to bother the kale if its more refined cousins are around.
Harvest single leaves, starting at the bottom of the plant. The taste, like that of Brussels sprouts, is greatly improved by frost, so there is no real point in hurrying the season. In recent years kale’s popularity has surged with the introduction of high performance Dutch and Japanese hybrid curly leaf kale varieties, and the re-introduction of an old Italian variety, know variously as Lacinato, Tuscan Black or Dinosaur kale.