Kale is usually grown from seed sown directly in the ground. Kale, which comes in a variety of colors, sizes and shapes, is prized for its tasty and nutritious leaves. Popular varieties include Winterbor Scotch, Red Russian and Lacinato. Do not purchase an ornamental variety if you intend to eat the plant.
Kale grows best in full sun, and in rich loamy soil high in nitrogen. If possible, select a patch that was recently occupied by pea plants, which enrich the soil with nitrogen. Add a generous amount of compost to the bed and turn it well with a pitchfork.
Kale is a cool weather crop, so it should be planted in early spring or late summer. Kale heads that mature in cooler weather are sweeter and more tender than those that mature in hot weather. Sow seeds 1/2" deep in rows spaced about 1' apart. Spacing within rows is not too essential as plants will be thinned out after germination. Lightly cover the seeds with soil and water well.
Kale seeds will germinate in about 10 days. When the seedlings reach about 9" tall, thin to one plant every 18" in the rows. Do so by carefully pulling the plant or by snipping it off at ground level with shears.
A thick layer of mulch around the plants serves a number of purposes. It keeps weeds down, preserves moisture, and keeps roots cool in summer and protected in cold weather. Kale doesn't have a lot of pest or disease problems, which makes it almost carefree. Remove yellowing outside leaves as they appear.
Kale matures in about 60 days. Because it does not keep well in the fridge, many gardeners harvest just what they intend to eat. Kale harvested after the first fall frost is very tender and sweet.