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Copenhagen Cabbage

Round Heading · Brassicaceae

Early compact cabbage that forms uniform globe-shaped light green heads on short stems. A strong fresh-market heirloom with firm texture and dependable cool-season performance. Key facts: 65 days to maturity, 6+ hours of sun, 15–18 " spacing. Not recommended for containers.

Updated April 19, 2026 · Backed by 4 cited sources
Overview

At a Glance

The essentials first: timing, light, spacing, seed-starting, container fit, and overall size.

Days to maturity
65 days
Sun
6+ hours
Full Sun In Cool Weather, 6 8+ Hours
Spacing
15–18 "
between plants
Seed start
4–6 weeks
before transplant
Container
Not recommended
Needs 5+ gal if attempted
Height
1–1.5 ft
at maturity
Planting window

Zone Planting Guide

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Care

Growing Guide

Everything in one place: seed starting, transplant timing, watering, soil, and structural support.

Seed starting
Germination
Time5–10 days
Optimal temperature70°F
Seed depth0.25"
Moving outdoors
Transplanting
Minimum soil temp45°F
Harden off7 days
Moisture
Watering
Weekly1–1.5 "
NeedsConsistent
Drip or soaker hose
Root zone
Soil
pH range6–7
PreferredFertile, Moisture Retentive, Well Drained Loam
Cabbage - Copenhagen seeds

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Cabbage - Copenhagen seeds

Compact. Plant in rows 2 1/2 feet apart, with 12-16 inches between plants.

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When you shop on Amazon using this link, SoilStack earns a small commission at no extra cost to you. It's how we keep the site free and the calendar ad-free. Every product on this page was hand-selected based on university extension research.

Jevrench Ultra Fine Garden Netting (4'x25')

Fine mesh blocks cabbage moths and flea beetles without chemicals. Lay over hoops at transplant time and leave on all season.

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Resilience

Plant Health

Stress tolerance, resistance notes, and the most common problems to watch for as plants mature.

Tolerance
Heat: Low Cold: High Drought: Low

Common Issues

Cabbage Worm Damage

Cause: Imported cabbageworm and loopers chew leaves and foul forming heads.

Prevention: Use floating row cover immediately after transplanting and scout undersides of leaves.

Head Splitting

Cause: Rapid water uptake after dry conditions can split mature heads.

Prevention: Keep watering even and harvest promptly once heads are firm.

Black Rot

Cause: Bacterial disease favored by warm wet conditions and splashing water.

Prevention: Use clean seed, rotate crops, and avoid overhead irrigation

Feeding & picking

Nutrition & Harvest

How hungry the plant is, what ripe harvest looks like, and how long the crop keeps after picking.

Feeding
Nutrition
Feeding intensityHeavy feeder
RecipesRoot Drench, Worm Castings Topdress, Compost Tea
Timing
Harvest

Heads feel hard and solid when squeezed and the outer wrapper leaves are still healthy.

Expected yield3–4 lbs/plant
Storage60 days — Hold near 32°F with high humidity for longest storage; home refrigerators keep it for several weeks.

Recommended fertilizer · paid link ?When you shop on Amazon using this link, SoilStack earns a small commission at no extra cost to you. It's how we keep the site free and the calendar ad-free. Every product on this page was hand-selected based on university extension research.

When you shop on Amazon using this link, SoilStack earns a small commission at no extra cost to you. It's how we keep the site free and the calendar ad-free. Every product on this page was hand-selected based on university extension research.

Espoma Tomato-Tone (4lb)

The fertilizer extension agents recommend. 3-4-6 NPK with 8% calcium to prevent blossom end rot. From the brand that's been in business since 1929.

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Plant relationships

Companion Planting

Helpful neighbors can support growth or deter pests. Keep antagonistic plants separated to reduce stress and competition.

What you'll need

Growing Supplies

Based on Copenhagen's growth profile -- recommendations matched to this variety's specific requirements.

Drip irrigation / soaker hose kit

Every gardener benefits from putting water at the root zone instead of on the leaves, because drip and soaker systems reduce foliar disease pressure by limiting leaf wetness and soil splash. A quality kit should include a backflow preventer, filter, pressure reducer, and UV-resistant tubing.

Source: Iowa State University Extension; Colorado State University Extension; UMass Extension

Soil test kit

A soil test gives a baseline for pH and nutrient status so gardeners can add only what the soil actually needs. Prioritize a mail-in or lab-affiliated kit whenever possible because extension guidance notes that laboratory testing is more accurate than instant readers.

Source: University of Maryland Extension; Purdue Extension; Montana State University Extension

Quality bypass pruners

Extension guidance favors bypass designs because they make cleaner, closer cuts on living tissue than anvil types. Look for hardened steel blades that can be sharpened, a comfortable grip, and a cutting capacity matched to real home-garden stems.

Source: University of New Hampshire Extension; Iowa State University Extension; Purdue University Extension

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Research

Sources

Reference material and extension guidance used to build this growing guide.

seed_catalog SeedsNowuniversity UMN Extensionuniversity OSU Extensioninference SoilStack crop synthesis
Internal links

Copenhagen Cabbage Planting Dates by Zone

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