How to Grow Cabbage

When cabbage grows best

Cabbage grows best around 60 to 65°F, according to Clemson Extension, and Utah State says growth and quality suffer once temperatures pass about 80°F. Heat brings slower growth, poorer heads and internal tipburn. Spring cabbage therefore needs to go in early enough to head before summer, and fall cabbage needs to be timed so heads form as the weather cools.

Cold is less of a threat. Maryland Extension says cabbage will survive 15 to 20°F, and Clemson gives 18 to 20°F for mature plants. The one cold risk is bolting: Clemson warns that 10 or more straight days between 35 and 50°F, after a period of good growth, can make plants flower instead of heading. A spring planting set out very early, followed by a long chilly spell, is the classic setup.

Starting from transplants or seed

Most gardeners use transplants in spring, because cabbage seed germinates better in warm soil. Colorado State notes this is why cole crops are usually transplanted in spring. Seed needs soil of at least 40°F and does best between 60 and 85°F. Utah State grows transplants for 6 to 7 weeks before planting out, until they have 4 to 6 true leaves. Maryland gives 4 to 6 weeks and Iowa State 4 to 5. Harden them off outdoors for several days first.

Set transplants out 2 to 3 weeks before the last frost; the dates for your zone above show this window. Seed can go in at the same time, ¼ to ½ inch deep.

For fall, Clemson notes that cabbage can be direct-seeded into the row. In the warmer parts of Colorado, including the Front Range, Colorado State says direct seeding in midsummer gives the best fall quality. Pick early varieties for fall: Iowa State recommends only early cultivars for its fall crop.

Spacing sets head size

Close spacing gives small heads and wide spacing big ones, so match the spacing to the variety:

• Utah State: 12 to 18 inches between plants, rows 2 to 3 feet apart.
• Maryland: 15 to 18 inches in the row, rows 30 to 36 inches apart.
• Iowa State: 18 to 24 inches, rows 24 to 30 inches apart.
• Clemson: 9 to 12 inches for 2- to 3-pound heads, in rows 36 to 44 inches wide.
• Texas A&M’s Rio Grande Valley guide: 18 to 24 inches, and as much as 30 to 36 inches for large Flat Dutch types.

Small, fast-heading varieties can also be planted in succession through the season, according to Maryland Extension.

Soil, feeding and water

Cabbage needs full sun, at least 6 hours and ideally 8 to 10, and fertile, well-drained soil rich in organic matter. Clemson recommends a pH of 5.8 to 6.5 and Iowa State 6 to 7. Have the soil tested and follow the report.

Feed once more during growth, then stop. Utah State side-dresses with ½ cup of 21-0-0 per 10 feet of row 4 weeks after planting, placed 6 inches from the plants and watered in. Extra nitrogen after heads start to form causes loose, split heads.

Water is where most heads go wrong. Utah State calls for 1 to 2 inches a week, applied deeply and less often; Iowa State says to irrigate whenever rain falls short of 1 inch a week. Cabbage roots are shallow, so cut weeds off at the surface with a sharp hoe rather than digging. A 2- to 3-inch straw or shredded-leaf mulch helps hold moisture.

Rotate cabbage-family crops. Iowa State suggests growing them in the same spot only once every 3 to 4 years.

Varieties by region

Extension services name different cabbages for their areas:

• Utah: Golden Acre, Ruby Ball (red), Savoy Ace and the storage type Danish Ball Head.
• Iowa: early Early Thunder, Quick Start and Stonehead; mid-season Blue Vantage, Thunderhead, Savoy Blue and Red Jewel; late Ruby Perfection.
• South Carolina: Bravo, Market Prize, Rio Verde, Savoy Express, Tropic Giant and Green Jewels (Clemson).
• Florida: Rio Verde, Flat Dutch, Round Dutch, Wakefield types, Copenhagen Market, Savoy and Red Acre (UF/IFAS).
• Lower Rio Grande Valley, Texas: Late Flat Dutch, Early Jersey Wakefield, Early Dutch, Caraflex and Megaton (Texas A&M).

Pests and problems

• Caterpillars. Imported cabbageworms, cabbage loopers and diamondback moth larvae chew holes and tunnel into heads. Use row covers, hand-pick, or spray Bt when caterpillars first appear. Nebraska Extension warns they can wipe out new fall transplants if left unchecked.
• Flea beetles. They pepper seedlings with tiny holes. Light damage barely affects yield, but protect young plants.
• Black rot. This bacterial disease makes V-shaped lesions on the leaves and spreads into the plant’s water-conducting tissue. It can come in on seed or transplants, so UF/IFAS and Clemson both say to start with clean, certified plants, and rotate.
• Split heads. Sudden water uptake near maturity bursts the head. Harvest on time, or pull up on the plant and twist it to break some roots.
• Tipburn. Inner leaf edges turn brown because calcium does not reach them during uneven growth. Steady watering and moderate feeding prevent it.

Harvest and storage

Harvest when the head feels firm and solid, usually 60 to 90 days after transplanting. Iowa State says you can start cutting at softball size. Cut below the head and leave 2 or 3 wrapper leaves on it. Each plant gives one head. Once ready, heads hold in the garden about 2 weeks in summer and 3 to 4 weeks in fall, according to Maryland Extension.

Refrigerated in a perforated bag, cabbage keeps 2 to 4 weeks. In a root cellar near 32°F with very high humidity it keeps for months; sources range from 3 to 4 months (Iowa State) to 2 to 6 months (Utah State). Store cabbage away from apples and pears, which make it bitter.