Cabbage: Sow and Grow Guide

Cabbage is hearty, versatile, stores well, and it may even be one of the showiest vegetables you ever grow. Head cabbage has round, overlapping leaves that grow loosely like a rose before tightening into a head, while napa cabbage grows in a cylindrical shape of tightly crinkled leaves that reveal a beautiful pattern when cut in half. Because you harvest the entire cabbage at one time, this is a good crop to grow in succession (not all at once) to have a continuous supply. If you were wondering how to grow cabbage from seed, you've come to the right place!

GENERAL SOWING

Head cabbage:

When to Sow Outside: 4 to 6 weeks before your average last frost date for a summer crop, or 10 to 12 weeks before your average first fall frost date for a fall crop.

When to Start Inside: RECOMMENDED. 6 to 8 weeks before your average last frost date, transplanting 2 to 4 weeks before your average last frost date. For fall crop, 4 to 6 weeks before transplanting outdoors in summer. Ideal soil temperature for germination is 75°-85°F. Mild Climates: Sow in fall for a cool-season harvest.

Napa cabbage

When to Sow Outside: RECOMMENDED. 2 to 4 weeks before your average last frost date for a summer crop or 8 to 10 weeks before your average first fall frost date for a fall crop. Ideal soil temperature for germination is 75°-85°F. Persistent temperatures of 50°F or below while plants are young can cause bolting (premature flowering), cover as necessary.

When to Start Inside: 4 to 6 weeks before your average last frost date transplanting after your average last frost date, and 4 to 6 weeks before transplanting outdoors in summer for a fall crop. Sow in biodegradable pots to avoid root disturbance. Mild Climates: Sow in fall for a cool-season harvest.

INDOOR SOWING

Use a lightweight seed-starting mix/medium (sterile, and lighter than potting mix), and sow seeds ¼" deep. Sow 2-3 seeds per pot, thinning to the strongest plant once leaves appear (clip extra plants at the soil level using scissors). The strongest plant may not be the tallest; look for thick, strong stems and deep color. By thinning early, you minimize the negative impact of crowding, like stretching for light. Read about more indoor sowing tips.

Containers

Containers should be clean, sanitized, and have drainage holes.

Transplanting

After hardening off, transplant seedlings 12" –24" apart. See packet for variety-specific spacing.

OUTDOOR SOWING

Sowing preparation and spacing

Cabbage grows best in well-drained soil that is rich in organic matter. It is always best to perform a soil test in the garden to see if your soil needs amendment.

Growing Temperature

Head cabbages grow best in temperatures below 80°F, which for some places may mean sticking to fall growing or choosing quick-maturing cultivars for a spring planting. Napa cabbage is less stressed by heat and can be grown all summer in many places. Napa plants are sensitive to temperatures under 50°F, which may cause bolting (premature flowering). Grow Napa cabbage in late summer/fall with ease or after the weather warms in spring, but be prepared to protect them if temperatures drop.

Thinning

When 3" tall, thin to 1 every 12" –24" apart. See packet for variety-specific spacing.

Water

Cabbage has shallow roots; water regularly. If soil is allowed to dry out during a warm spell and followed by a deep watering, heads may split.

Fertilization

Cabbage is a heavy feeder. If soil is deficient, add a balanced fertilizer (equal parts nitrogen, phosphorus, and potassium) or a nitrogen-rich fertilizer prior to sowing/transplant. Adding compost or a balanced fertilizer on top the soil over the root zone ("side dressing") a couple times as plants grow is also beneficial.

Weeding

Keep plants well weeded. Weeds compete with crops for light, nutrients, and water, and can harbor insects and diseases.

Special care

When transplanting seedlings from indoors, bury stem up to lowest leaves. Protect with row covers or caps in early spring if temperatures drop below 30°F for head cabbage; 50°F for Napa cabbage. Add row covers at transplant time to exclude common pests like cabbage moths. Row covers may remain until harvest. Mulch around plants to keep soil cool and moist. If cabbage loopers are a problem, spray with Bacillus thuringiensis (an organic bacteria that kills caterpillars). Rotate Brassica crops so they are grown in the same area only once in three years to prevent the buildup of diseases in the soil.

HARVESTING

Head cabbage

Harvest heads when they are well developed, firm, and solid when squeezed. Overly mature head cabbage is prone to splitting. Cut off heads at base with a sharp knife. Harvest in the morning if possible. If harvested in the heat, dunk in ice water to reduce "field heat" and increase storage time. Allow to drain before storing.

Napa

Harvest when heads have reached mature size according to information on the packet. Cut off heads at base with a sharp knife. Cabbages left in the ground beyond maturity are more subject to disease and splitting. Harvest in the morning if possible. Dunk in ice water to reduce "field heat" and increase storage time. Allow to drain before storing.

STORAGE

Stores longest if wrapped in plastic wrap or placed in a sealed container to slow evaporation.

COMMON PESTS AND DISEASES

Napa cabbage is prone to flea beetle damage. Organic neem oil or a homemade garlic and hot pepper spray can keep flea beetles at bay. All types of cabbages can be plagued by different cabbage-loving caterpillars like cabbage loopers and cabbage moths. You can scout and hand-pick caterpillars off or use Bacillus thuringiensis. The simplest way to prevent these pests is to use row cover, which excludes the adult egg-laying butterflies and moths.