Cool-loving brassicas add colors, nutrition

Your Show-Me Garden: MU Extension brings you gardening tips from experts around the state.

COLUMBIA, Mo. – Plant brassicas now so they mature before summer’s heat arrives, said University of Missouri Extension horticulturist David Trinklein. They are “nutritional powerhouses” that thrive in cool weather.

Members of the mustard family, brassicas are easy to grow and can be planted again in early fall, giving gardeners a double crop of these nutritious vegetables, said Trinklein. The sunny, cool days and crisp nights of fall produce the best-tasting brassicas.

Full of nutrition, color and texture, brassicas include cabbage, cauliflower, collards, broccoli, Brussels sprouts, kale, bok choy, rutabagas, turnips and kohlrabi. Their popularity goes back to the era of the Chinese philosopher Confucius, said Trinklein.

The National Garden Bureau has named brassica its 2017 vegetable of the year.

Brassicas also are known as cole crops. “Cole” comes from the Latin word caulis, denoting the stem or stalk of the plant.

Brassicas provide vitamin C and soluble fiber to the diet. They also offer large doses of glucosinolates, which are sulfur-containing compounds that have been shown to reduce the risk of some digestive tract cancers. These benefits come with one unpleasant side effect. Many brassicas, especially cabbage, give off a pungent odor when cooking.

Red brassicas, such as red cabbage, also provide megadoses of the antioxidant anthocyanin.

You can grow all brassicas from seed, but most are better suited to establish in the garden as transplants, or ready-grown seedlings. These include plants prized for their “heads” such as cabbage, cauliflower and broccoli.

Harden off transplants to improve frost hardiness, Trinklein said. Brassicas grow best in well-drained loam soil. They are not heavy feeders. Use a standard pre-plant fertilizer. Later, side-dress plants lightly with a water-soluble fertilizer rich in nitrogen for bigger heads of cabbage, broccoli and cauliflower.

Space plants 12-24 inches apart, depending on the cultivar, to avoid overcrowding. Brussels sprouts grow in a columnar fashion and don’t need as much space.

Harvest cabbage when the head is firm. Cabbage heads split when past their peak or not watered properly. Cut heads with a sharp knife. Discard the root to make way to plant another vegetable.

Harvest broccoli and cauliflower when the buds are full but tight. If you wait too long, the plants become too fibrous. Broccoli may continue to grow and produce some smaller shoots after the main head is cut.

Sow turnips, collards, kale and others from seed. Pick leaves when tender. The plant continues to produce leaves. Discard plants when days grow hotter.

Since pests and diseases linger in the soil, crop rotation in the garden is a good way to combat pest problems. Early detection is critical for effective control, Trinklein said. Check for European cabbage looper and cabbageworm; their adult stage is a small moth and butterfly, respectively. Hand pick pests when possible; make sure to look on the underside of plants. For chemical pest control that meets organic standards, dust plants with rotenone.