Chard is a green with a mild, earthy flavor. In my zone 6 garden, I sow it directly in the garden after my last frost date, and it continues to grow until our first hard frost, without bolting. The key to keeping it going is to harvest the outer leaves, leaving the inner part of the plant intact. New leaves will form in the center, and you'll have a constant supply of chard.
In addition to the leaves, which can be eaten raw or cooked like spinach, the celery-like stems are delicious as well.
Chard is very high in vitamin A, with one cup of chopped leaves coming in at over 200% of the recommended daily allowance. In addition, chard is high in vitamin C and iron.
Delicious chard varieties: 'Bright Lights,' 'Ruby Chard.'
If you grow beets, you get a two-fer. The roots, of course, are delicious and nutritious. But if you toss the greens when you're preparing your beets, you're missing out on a real delicacy. Beet greens are very high in vitamin A and C, and they have a delicious, mild flavor. They are delicious sautéed or steamed, and baby beet greens are wonderful served raw in a salad. Sow a few seeds every few weeks throughout the growing season so you'll have a constant supply of baby greens on hand.
Delicious beet varieties: 'Detroit Dark Red,' 'Chiogga'
Kale is one of those powerhouse vegetables that every doctor wishes we would eat more of. Besides being high in vitamin C, and folate, kale is also high in iron, vitamin A, and calcium. Most of us associate kale with the dark green, curly-leafed offerings at the grocery store. In fact, there are several delicious varieties of kale, and they are just as attractive as they are delicious. Two good ones to look for are 'Red Russian,' which has beautiful stems, and 'Lacinato,' which has amazing bluish-green leaves.
Kale can be eaten steamed, sautéed, or cooked into a wide variety of soups, stews, and stir-fries. It goes all season long after being sown a couple of weeks before the last frost date, and will grow straight through fall.