Cabbage

Cabbage is a cool-weather vegetable grown for its dense head of leaves. The plant is a biennial, which means it needs two growing seasons, but gardeners usually treat it as an annual. Heads can be rounded, oval or pointed, and the leaves range from smooth to crinkled and from light green to reddish. Varieties named on gardening experts page include ‘Bronco’, Conqueror, ‘Famosa’, ‘Piccadilly’, ‘Ruby Perfection’ and ‘Tiara’, with heads from about 1 to 8 pounds. Mature plants are about 10 inches to 2 feet tall (25 to 61 cm), and the leaves have the best flavor after a frost.

Sow seeds ¼ to ½ inch (6 to 13 mm) deep, 2 to 3 weeks before the last spring frost, or set out transplants at that time. Gardening experts’s guide says cabbage should be grown in early spring or fall, that transplants suit spring planting, and that fall crops can be direct seeded. In Maryland, spring crops are started indoors 4 to 6 weeks before setting plants out in mid-April to early May, and fall crops are sown about 3 weeks before transplanting. Cabbage can be grown from seed or transplants.

Spacing. Guides give different spacing. Utah suggests 12 to 18 inches (30 to 46 cm) apart in rows 2 to 3 feet apart. Iowa suggests 18 to 24 inches (46 to 61 cm) apart. Gardening experts suggest 9 to 12 inches (23 to 30 cm) apart for 2 to 3 pound heads. Close spacing gives smaller heads. For direct-seeded rows, thin plants when they reach the three-leaf stage.

Soil. Cabbage grows in a range of soils but prefers well-drained, fertile ground rich in organic matter. Get a soil test before planting. Gardening experts give a soil pH of 5.8 to 6.5, while gardening experts list a neutral range of 6.0 to 8.0.

Sun. Plant in full sun, meaning at least 6 hours of direct sun a day.

Watering. Keep the soil evenly moist and water deeply, about 1 to 2 inches (2.5 to 5 cm) a week. Iowa suggests weekly watering if rain does not supply 1 inch (2.5 cm) per week. Water about every three days until seedlings are established. Gardening experts suggest watering in the morning so foliage dries before dark, and wetting the soil at least 6 inches (15 cm) deep.

Feeding. Where no soil test has been done, gardening experts suggest a 5-10-10 fertilizer before planting and a side-dressing during the season. Utah suggests a nitrogen fertilizer about 4 weeks after planting or thinning, and no extra nitrogen once heads start to form.

Weeds and mulch. Cabbage roots are shallow, so slice weeds off at ground level with a sharp hoe. A 2 to 3 inch (5 to 8 cm) layer of mulch such as straw helps control weeds and keep moisture in.

Gardening experts list imported cabbageworm, cabbage looper, diamondback moth caterpillar, harlequin bugs, cabbage maggots, aphids and flea beetles as the major insect pests. Iowa says cabbageworms chew large irregular holes and can be treated with products containing Bacillus thuringiensis (Bt). Flea beetles leave small round holes, called shothole damage.

Black rot is the most serious disease in gardening experts’s guide. It causes V-shaped lesions on leaves, has no control once it is established, and can come on transplants or seed. Gardening experts recommend buying certified disease-free transplants or chemically treated seed. Crop rotation within the cabbage family helps reduce pest and disease pressure.

Tipburn, a browning of leaf edges in the inner head, comes from water stress and too much fertilizer during head development. Spring cabbage must mature before temperatures get too hot, and Maryland lists bolting among common cabbage problems.

Harvest when the heads are firm and full size. Iowa says heads can be cut once they are firm and about the size of a softball. Maturity times differ: Maryland gives 60 to 90 days from transplanting, gardening experts give 60 to 80 days after planting transplants, and Iowa gives 60 to 100 days after planting transplants, depending on the variety.

Cut the stem below the head, leaving 2 to 3 outer wrapper leaves for protection. Move harvested heads out of direct sun quickly, because direct sun can cause sunblistering and weight loss. Heads split if they are left too long, so harvest promptly.

Store harvested cabbage in the refrigerator. Gardening experts suggest a cold, moist spot such as the vegetable drawer. Guides give different storage times: gardening experts say up to five months at 34 °F (1 °C) and 98% humidity; Utah says 2 to 6 months at 32 °F (0 °C) and 95% relative humidity; Iowa says 2 to 4 weeks in a perforated plastic bag in the refrigerator. Keep cabbage away from apples and pears, which can make it taste bitter.

Gardening experts page tags cabbage as a problem for horses, but it gives no detail about which part of the plant or how much is involved. The leaves are described as edible for people. None of the pages reviewed rate cabbage’s toxicity for people, cats or dogs, so no such rating is given here.