← Plant Guides

How to Grow Purple Cape Broccoli

Wikimedia Commons

Purple Cape Broccoli

Brassica oleracea var. italica

vegetable

Purple Cape is a heirloom broccoli variety distinguished by its deep purple florets and smaller, more delicate heads compared to green varieties. It offers a sweeter, more nutty flavor than standard broccoli and produces side shoots after the main head is harvested. This cold-hardy brassica is prized by gardeners for its ornamental appeal and extended harvest season.

When should you plant Purple Cape Broccoli in your zone?

Get a personalized planting timeline — when to start seeds, transplant, and harvest — based on your USDA zone and local frost dates. Free to start.

Get my Purple Cape Broccoli timeline →

Example Purple Cape Broccoli timeline · Pittsburgh, PA (Zone 6b)

  1. Plant Purple Cape Broccoli

    Around Apr 17

    Near Pittsburgh's average last spring frost.

  2. Tend & protect

    Late spring–summer

    Watering, feeding, and pest-watch reminders.

  3. Harvest Purple Cape Broccoli

    Around Jun 11

    ≈ 55 days after planting

Sample dates for Pittsburgh, PA. Sign up to get exact Purple Cape Broccoli dates for your own zip code.

Growing Conditions

☀️
Sun: Full sun, 6-8 hours daily minimum
💧
Water: Consistent moisture; 1-1.5 inches per week. Keep soil evenly moist but not waterlogged. Mulch to retain moisture and regulate soil temperature.
📏
Spacing: 18 inches
📅
Days to maturity: 55-100 days
🌱
Planting depth: 0.25-0.5 inches for seeds; transplants 1-2 inches deep

Soil

Type: Well-draining, fertile loamy soil rich in organic matter
pH: 6.0-7.5
Amendments:
Compost Aged manure Calcium (lime if pH is low) Balanced fertilizer (10-10-10)

Growing Zones

Find your zone →

Zones 4-8 ideal; thrives in cool-season climates

3a 3b 4a 4b 5a 5b 6a 6b 7a 7b 8a 8b 9a

Sign up free to see if Purple Cape Broccoli grows in your zone — and get a personalized planting timeline.

Get my Purple Cape Broccoli timeline →

Growth Stages

1

Seedling

7-14 days

Tiny cotyledons emerge, followed by first true leaves. Plant is fragile and low-growing.

Maintain consistent moisture and moderate light (14-16 hours if indoors). Keep soil warm (65-75°F). Thin seedlings to prevent damping-off.

2

Vegetative Growth

3-4 weeks

Plant develops 4-6 true leaves and a sturdy stem. Foliage is large, blue-green, and deeply textured.

Transplant outdoors when 4-6 weeks old or 4 true leaves appear. Harden off gradually. Keep soil moist and provide consistent nutrients. Monitor for cabbage worms.

3

Head Formation

3-4 weeks

Central flowering head begins to form as a tight cluster of purple buds. Plant reaches full size with extensive foliage.

Provide consistent watering and balanced fertilizer every 2-3 weeks. Ensure adequate calcium to prevent tip burn. Watch for pests. Head forms best in temperatures 60-70°F.

4

Head Maturity

1-2 weeks

Main purple head is fully formed, dense, and firm with no visible flowers opening. Buds are tight and uniform in color.

Begin harvesting when head is firm but before florets begin to separate. Maintain moisture to support continued growth of side shoots.

5

Side Shoot Production

4-8 weeks

After main head harvest, numerous smaller purple shoots emerge from leaf axils along the stem, extending the harvest period.

Continue consistent watering and fertilizing. Harvest side shoots when 4-6 inches long for continued productivity over several weeks.

Companion Planting

Plan your garden →

Plant with:

Beets Chamomile Dill Garlic Lettuce Onions Potatoes Spinach Thyme

Avoid planting near:

Cabbage Cauliflower Kale Other brassicas (spacing disease and pest issues) Fennel Kohlrabi

Common Pests

  • Use row covers before butterflies lay eggs. Hand-pick caterpillars. Apply Bt (Bacillus thuringiensis) spray every 7-10 days. Encourage parasitic wasps.

  • Similar to cabbage worm; use Bt spray, row covers, and hand-picking. Neem oil can be effective.

  • Use row covers on seedlings. Spray with kaolin clay or neem oil. Encourage beneficial insects. Remove affected leaves.

  • Strong water spray to dislodge. Insecticidal soap or neem oil. Encourage ladybugs and parasitic wasps. Reflective mulch may deter.

  • Rotate crops (3-year minimum). Improve drainage. Lime soil to raise pH above 7.0. Remove and destroy affected plants. Use disease-resistant varieties if available.

Uses

🍳

Fresh eating and cooking

Culinary

Purple Cape broccoli can be steamed, roasted, stir-fried, or eaten raw. Its sweeter, nuttier flavor compared to green broccoli makes it excellent in salads, as a crudité, or lightly cooked to preserve the purple color and tender texture. [source]

🍳

Preservation

Culinary

Purple Cape broccoli freezes well for long-term storage. Blanch for 3 minutes, chill in ice water, drain, and freeze in bags. It can also be pickled or fermented. [source]

💊

Nutritional and health benefits

Medicinal

Like all broccoli, Purple Cape is rich in glucosinolates, sulforaphane, and anthocyanins (the source of its purple color), compounds with potential anti-cancer and anti-inflammatory properties. It provides vitamin C, folate, fiber, and minerals. [source]

🏠

Garden ornament

Household

Purple Cape's striking purple florets and attractive blue-green foliage make it both productive and visually appealing in the vegetable garden or ornamental beds. [source]

🦋

Pollinator and beneficial insect support

Wildlife

If any flowers are left to open (late in the season), they will attract bees and other pollinators. The plant also provides habitat and host material for beneficial insects. [source]

This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.

Harvest Tips

Harvest the main head when it is firm, dense, and purple with tightly clustered buds, typically 55-100 days after planting. Cut the central head 5-7 inches below the flower cluster with a sharp knife, leaving the stem and leaves intact. Side shoots will develop from leaf axils; harvest these when 4-6 inches long, cutting just above a leaf node. Continue harvesting side shoots until frost or plant decline. Harvest in early morning for best flavor and texture. Avoid harvesting when florets are beginning to separate or yellow flowers are opening.

Fun Facts

  • 🌱 Purple Cape is an heirloom variety that dates back to the 19th century and was particularly popular in European gardens before green broccoli hybrids dominated the market.
  • 🌱 The purple color comes from anthocyanins, the same pigments found in blueberries and red cabbage—these compounds are heat-stable, so the color persists even when cooked.
  • 🌱 A single Purple Cape plant can produce 8-12 or more side shoots after the main head is harvested, making it more prolific than many modern hybrid broccoli varieties over an extended season.

Gardening Terms

New to gardening? Learn about terms used in this guide:

Full Sun Heirloom Mulch Transplant True Leaves
Shop Purple Cape Broccoli plants and related plants at Plant Addicts →

Join 30,000 gardeners planning their gardens with LizPlants.

Get your personalized Purple Cape Broccoli planting timeline

Tell us your zip code and we'll calculate exactly when to start Purple Cape Broccoli seeds, transplant seedlings, and harvest — based on your USDA zone and local frost dates. Includes calendar reminders and printable task lists. Free to start.

Get my Purple Cape Broccoli timeline →