Cabbage thrives in cool weather. In most areas, you can plant an early crop for fresh eating and a late crop—usually the more problem free and tastier crop—primarily for winter storage.
Set out early types 4 weeks before the last expected frost date. Plant in garden 12 to 24 inches apart, in rows 18 to 34 inches apart. Use closer spacings for smaller, early varieties, wider spacings for larger, late-season varieties. Wide spacings produce bigger heads, but young, small cabbages are tastier. To get both, harvest every other one before maturity. Stagger plantings at 2-week intervals for a longer harvest.
Start your late crop in midsummer. Space these seedlings farther apart than the spring crop, and place them so a tall crop, such as corn or pole beans, provide some afternoon shade.
Prepare soil by incorporating aged compost into the soil. Side-dress seedlings with rich compost 3 weeks after planting. Plants have shallow root systems. Avoid even shallow cultivation. Mulch to protect roots, reduce weed competition and conserve moisture. Uneven watering can cause a sudden growth spurt that will make the developing head split. If you see a cabbage head starting to crack, twist the plant a half turn and pull up to slightly dislodge the roots and thus slow the plant’s growth. Or use a spade to cut the roots in one or two places 6 inches below the stem. This also helps to prevent cabbage from bolting (producing a flower stalk).
Avoid wetting the foliage during cool weather or periods of high humidity, because constantly wet leaves are prone to disease. Cut back on water as cabbage matures. If leaves start to yellow, provide a mid-season fertilizer boost.
Major cabbage pests include cabbage maggots, imported cabbageworms, cabbage loopers, and cutworms. The harlequin bug, a small shiny black insect with red markings, causes black spots and wilting leaves; control by hand picking or applying insecticidal soap. Slugs may chew ragged holes in leaves. Use floating row cover to protect crop from early pests.
Black leg, a fungal disease, forms dark spots on leaves and stems. Black rot symptoms include black and foul-smelling veins. Club root prevents water and nutrient absorption. Fusarium wilt, also known as yellows, produces yellow leaves and stunted heads. Remove and destroy plants affected by these diseases. If club root has been a problem in your garden, test soil pH before planting and add ground limestone if needed to raise the pH to at least 6.8
Good growing conditions, crop rotation, and the use of disease-resistant cultivars are the best defenses against cabbage-family crop problems. Also, thoroughly clean up the garden at the end of the season, removing all remaining leaves and roots. To help reduce disease, do not plant cabbage or other cole crops in the same location more than once every three or four years.
Use a sharp knife to cut heads when they are firm. Leave stalks and roots in place to produce tasty little cabbages; eat them like Brussels sprouts or let them develop into a second crop of small heads. Fresh cabbage has the best taste, but late-season cultivars keep well in a moist, cool place (32° to 40°F) for 5 to 6 months. Use split heads for making sauerkraut.