How to Grow Sweetheart Purple Cabbage
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Sweetheart Purple Cabbage
Brassica oleracea var. capitata
vegetableSweetheart Purple is a red/purple cabbage variety known for its deep magenta color, tender texture, and sweet flavor. It forms dense, compact heads that are excellent for fresh eating, cooking, and pickling. This cold-hardy brassica is both nutritious and ornamental in the garden.
When should you plant Sweetheart Purple Cabbage in your zone?
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Example Sweetheart Purple Cabbage timeline · Pittsburgh, PA (Zone 6b)
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Plant Sweetheart Purple Cabbage
Around Apr 17Near Pittsburgh's average last spring frost.
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Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
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Harvest Sweetheart Purple Cabbage
Around Jun 26≈ 70 days after planting
Sample dates for Pittsburgh, PA. Sign up to get exact Sweetheart Purple Cabbage dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 2-9; cool-season crop, excellent for spring and fall harvests
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Seedling
3-4 weeksTiny plants with 2-4 true leaves, pale green color
Maintain consistent moisture and temperatures of 65-75°F. Provide bright light to prevent leggy growth. Thin seedlings if direct seeding.
Transplant/Establishment
2-3 weeksYoung plants with 6-8 true leaves, ready for garden transplanting
Harden off seedlings before transplanting. Plant deep (up to first true leaves) to encourage strong roots. Water well after transplanting.
Vegetative Growth
4-6 weeksRosette of blue-green leaves spreading outward; no head formation yet
Maintain consistent watering and apply nitrogen fertilizer every 2-3 weeks. Monitor for pests. Remove any yellow or damaged outer leaves.
Head Formation
3-4 weeksLeaves begin to cup and compact; dense purple head forms at center
Reduce nitrogen and switch to balanced or phosphorus-heavy fertilizer. Water consistently to prevent cracking. Ensure adequate spacing for air circulation.
Harvest Maturity
Ready to harvest, can stay in ground for weeksCompact, solid head with deep purple color; outer leaves waxy and protective
Harvest when head is firm and size is desired. Can tolerate light frost (flavors improve). Cool conditions may delay maturity or extend harvest window.
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Install fine mesh row covers; apply Bt (Bacillus thuringiensis) every 7-10 days; handpick; encourage parasitic wasps
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Row covers; Bt spray; neem oil; hand removal of larvae
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Row covers on young plants; kaolin clay; neem oil; diatomaceous earth
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Handpick; remove and destroy eggs on leaf undersides; neem oil; crop rotation
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Strong water spray; insecticidal soap; neem oil; encourage beneficial insects like ladybugs
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Improve soil drainage; lime acidic soils; rotate brassicas; avoid planting in infested soil for 7-10 years
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Remove infected plants; disinfect tools; improve air circulation; avoid overhead watering; use disease-resistant varieties
Uses
Fresh salads and slaws
CulinarySweetheart Purple's tender texture and sweet flavor make it ideal for raw preparations. Its vibrant purple color adds visual appeal to salads, coleslaws, and pickling projects. [source]
Cooking and braising
CulinaryThe mild, slightly sweet cabbage works well braised, sautéed, or roasted. Purple cabbage retains its color better than red varieties when cooked properly. [source]
Nutritional support and antioxidants
MedicinalRich in anthocyanins, vitamin C, and sulforaphane, purple cabbage supports immune function and digestive health. Often consumed fresh or as fermented sauerkraut for probiotic benefits. [source]
Natural pH indicator
HouseholdThe anthocyanin pigment in purple cabbage juice changes color with pH levels, making it useful as a natural pH indicator or acid-base demonstration. [source]
Natural dye source
CraftPurple cabbage can be used to create natural dyes for textiles and other craft projects. The resulting colors vary based on pH adjustments. [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 when the head feels firm and dense, about 3-4 inches in diameter (or larger if desired). Cut at the base with a sharp knife. Can be harvested at any size from mini to full maturity. Sweetheart Purple improves in flavor after a light frost. Store in cool conditions (32-40°F, high humidity) for 2-3 months. Can be left in the ground through light frosts in fall.
Fun Facts
- 🌱 Sweetheart Purple cabbage's deep purple color comes from anthocyanins, the same pigments that make blueberries blue. These compounds act as powerful antioxidants.
- 🌱 The cabbage plant can survive temperatures as low as 20°F, and frost can actually enhance sweetness by converting starches to sugars.
- 🌱 A single mature Sweetheart Purple head can weigh 2-4 pounds and contains roughly 60% water, making it extremely low in calories but high in nutrients.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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