What hardiness zones is Brassica oleracea 'Copenhagen Market' suitable for?

Brassica oleracea 'Copenhagen Market' is Copenhagen Market cabbage, an annual vegetable reaching 12–15 inches (30–38 cm) tall and 18–24 inches (45–60 cm) wide with an upright compact habit — a central round head surrounded by wrapper leaves. The cultivar is a Danish heirloom dating to the early 1900s that produces round dense solid heads 6–8 inches (15–20 cm) in diameter weighing 3–4 pounds (1.4–1.8 kg) with blue-green wrapper leaves and a pale green interior. The head is short-cored with tender smooth-textured interior leaves. Maturity is 65–75 days from transplant. The cultivar is a cool-season crop with moderate growth rate. Heads hold in the field through light frost, and flavor improves after a light freeze. The round early cabbage is widely adapted across temperate climates and is a reference cultivar for home-garden cabbage production. Family Brassicaceae.

Native Range

The parent species Brassica oleracea (cabbage group) is descended from wild cabbage native to coastal western and southern Europe. 'Copenhagen Market' is a Danish heirloom from the early 1900s.

Suggested Uses

Grown in vegetable gardens and containers of 5 gallons (19 L) or larger for culinary use in coleslaw, sauerkraut, cooked dishes, and salads. The round 3–4 pound dense heads and the smooth-textured interior suit both fresh eating and short fermentation. The cultivar's shorter storage life (2–4 weeks refrigerated) separates it from long-term storage cabbages, so the harvest is used fresh rather than stored for winter. Head splitting occurs if watering is irregular. Cool-season crop — not suitable for summer-heat production in warm regions.

How to Identify

Identified by round dense 3–4 pound (1.4–1.8 kg) heads 6–8 inches (15–20 cm) in diameter with blue-green wrapper leaves and a pale green short-cored interior, maturing in 65–75 days from transplant. Separated from 'Early Jersey Wakefield' by the round (versus conical or pointed) head shape and the slightly later maturity (65–75 versus 60–70 days). Separated from long-term storage cabbages by the shorter storage life (2–4 weeks refrigerated) and the smooth-textured interior.

Appearance

Size & Dimensions

Height1' - 1'3"

Width/Spread1'6" - 2'

Colors

Flower Colors

yellow

Foliage Colors

blue

Fall Foliage Colors

no change

Bloom Information

Grown as an annual for head production; the plant does not bloom at harvest stage. Four-petaled yellow flowers on stalks 3–4 feet (0.9–1.2 m) tall appear only if the crop is overwintered or vernalized (bolting), which splits the head and ends usable production. Harvest occurs when heads are firm and solid.

Detailed Descriptions

Flower Description

Yellow; four-petaled; only if bolting

Foliage Description

Blue-green wrapper leaves surrounding pale green interior; round dense head

Growing Conditions

Sun Requirements

Full Sun

Requires 6-8 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range6.0 - 7.5(Neutral)

357912

Soil Types

loam

Drainagewell drained

Water & Climate

Water Needs

High

Frost Tolerance

hardy

Time to Maturity

65-75 days from transplant

Care & Maintenance

Care Guide

Seed is started indoors 6–8 weeks before the last frost date. Transplants are hardened off and planted out at 18–24 inch (45–60 cm) spacing in rich moist well-drained soil at pH 6.0–7.5. Consistent moisture through head formation reduces splitting — irregular watering after a dry period causes heads to crack. The cabbage group is a heavy feeder; side-dressing with nitrogen-rich fertilizer at 4 weeks after transplant supports head formation. Harvest occurs when heads are firm and solid, 65–75 days from transplant. Heads hold through light frost, which improves flavor.

Pruning

Pruning is not applicable. The entire head is harvested by cutting at the base of the stalk. Lower leaves and the stump are left in place to produce small secondary heads over the next few weeks in favorable conditions.