How to Grow Brassicas (Cabbage & Kale)

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Brassicas (Cabbage & Kale)

Brassica oleracea

vegetable

Brassicas are cool-season cruciferous vegetables that include cabbage, kale, broccoli, and cauliflower. They are nutrient-dense crops rich in vitamins C and K, fiber, and glucosinolates with potential anti-cancer properties. These hardy plants thrive in cool weather and can tolerate light frosts, making them ideal for spring and fall gardens.

Looking for a specific variety?

Napa Lacinato Curly Scotch Red Acre Savoy Brussels Sprouts Genovese

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Example Brassicas (Cabbage & Kale) timeline · Pittsburgh, PA (Zone 6b)

Plant Brassicas (Cabbage & Kale)
Around Apr 17

Near Pittsburgh's average last spring frost.
Tend & protect
Late spring–summer

Watering, feeding, and pest-watch reminders.
Harvest Brassicas (Cabbage & Kale)
Around Jun 16

≈ 60 days after planting

Sample dates for Pittsburgh, PA. Sign up to get exact Brassicas (Cabbage & Kale) dates for your own zip code.

Growing Conditions

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Sun: Full sun, 6-8 hours daily minimum; afternoon shade beneficial in hot climates

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Water: Consistent moisture; 1-1.5 inches weekly. Water at soil level to prevent fungal diseases. Mulch to retain soil moisture and regulate temperature.

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Spacing: 12-18 inches between plants (varies by variety; cabbage needs more space than kale) inches

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Days to maturity: 60-120 days depending on variety and whether direct-seeded or transplanted

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Planting depth: 0.25-0.5 inches for seeds; transplants should be set at same depth they were growing

Soil

Type: Well-draining, fertile loamy soil rich in organic matter

pH: 6.0-7.5

Amendments:

Nitrogen-rich compost Well-rotted manure Blood meal or fish emulsion Kelp meal for trace minerals Aged mushroom compost

Growing Zones

Find your zone →

Zones 3-9; prefer temperatures 45-75°F

2a 2b 3a 3b 4a 4b 5a 5b 6a 6b 7a 7b 8a 8b 9a 9b

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Growth Stages

Seedling

3-4 weeks

True leaves emerge within 5-10 days. Plants develop first set of characteristic lobed leaves.

Keep soil consistently moist but not waterlogged. Provide bright light indoors if starting seeds. Thin seedlings to prevent crowding. Apply balanced liquid fertilizer weekly.

Vegetative

4-6 weeks

Rapid leaf development; plant establishes strong root system and multiple leaf layers. Leaves expand significantly and develop deeper color.

Begin applying nitrogen-rich fertilizer every 2-3 weeks. Side-dress with compost or blood meal. Mulch around plants. Remove any yellowing lower leaves. Scout for pests and diseases.

Head Formation (Cabbage) / Mature Leaf Development (Kale)

6-8 weeks

For cabbage: outer leaves wrap around developing head center, creating dense sphere. For kale: plant reaches full height with frilly or curly leaves.

Maintain consistent nitrogen and moisture. For cabbage, ensure adequate spacing to prevent head rot. Apply copper fungicide if downy mildew appears. Continue mulching.

Head Maturation (Cabbage) / Leaf Harvest Ready (Kale)

2-3 weeks

Cabbage head becomes firm and dense; outer leaves may yellow slightly. Kale develops full flavor after light frost (sugars increase).

Reduce nitrogen to prevent excess leaf growth. Maintain even watering. For cabbage, pressure-test head firmness daily. Kale benefits from temperatures below 50°F.

Harvest

Ongoing (kale); One-time (cabbage)

Cabbage heads reach full size and firmness. Kale leaves are tender and flavorful; plant continues producing new leaves.

Harvest cabbage when head is firm; cut at base with sharp knife. For kale, pick outer leaves first, leaving center growing point intact for continued harvest.

Companion Planting

Plan your garden →

Plant with:

Beets Onions Garlic Dill Chamomile Oregano Thyme Potatoes Celery Spinach

Avoid planting near:

Tomatoes Peppers Fennel Strawberries Pole beans Mustard greens (same family, compete for nutrients)

Common Pests

Row covers until flowering of host plants. Bacillus thuringiensis (Bt) spray. Hand-pick larger caterpillars. Encourage parasitic wasps.
Bt spray every 7-10 days. Spinosad organic insecticide. Remove by hand. Maintain beneficial insect populations.
Row covers on seedlings. Neem oil spray. Diatomaceous earth dust. Remove debris where they overwinter.
Reflective mulches. Yellow sticky traps. Insecticidal soap spray. Strong water spray to dislodge.
Strong water spray. Insecticidal soap. Neem oil. Encourage ladybugs and lacewings.
Lime application to raise pH. Crop rotation (3-4 years). Remove infected plants immediately. Resistant varieties like 'Resistant Red Acre'.
Remove infected leaves. Improve air circulation. Copper fungicide spray. Avoid overhead watering.

Uses

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Nutrient-dense fresh vegetables

Culinary

Cabbage and kale are staples in cuisines worldwide, used raw in slaws and salads, steamed, braised, or fermented into sauerkraut and kimchi. Rich in vitamins C, K, A, and B6, plus minerals like potassium and manganese. [source]

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Anti-inflammatory compounds

Medicinal

Brassicas contain glucosinolates that convert to sulforaphane, compounds studied for anti-cancer and anti-inflammatory properties. Regular consumption may support immune function and reduce chronic disease risk. [source]

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Fermentation and preservation

Household

Cabbage ferments beautifully into probiotic-rich sauerkraut and kimchi, extending shelf life to months while enhancing bioavailability of nutrients. Traditional preservation method used for centuries. [source]

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Pollinator and beneficial insect support

Wildlife

If allowed to bolt, brassicas produce small yellow flowers that attract bees, butterflies, and beneficial insects. These blooms also support parasitoid wasps that control pest caterpillars. [source]

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Texture and flavor variation

Culinary

Different brassica types offer diverse culinary options: tender kale for smoothies, crispy cabbage for slaws, mild Napa cabbage for stir-fries, and sweet Lacinato kale for chips. Each has distinct flavor profiles. [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 cabbage when heads feel firm and solid (usually 70-120 days from transplant). Cut at the base with a sharp knife. For spring crops, harvest before temperatures exceed 75°F to prevent splitting. Kale can be harvested continuously by removing outer leaves; pick in morning after dew dries for best flavor and nutrient density. Kale actually improves in flavor after first frost. Store cabbage heads in cool, humid conditions (32-40°F); kale best used fresh or blanched and frozen within days of harvest.

Fun Facts

🌱 Kale is among the most nutrient-dense foods per calorie, with a single cup of raw kale providing over 100% of daily vitamin K requirements. This same nutrient is crucial for blood clotting and bone health.
🌱 Cabbage has been cultivated for over 4,000 years and was highly valued by ancient Greeks and Romans for both food and medicinal purposes, particularly as a digestive aid.
🌱 Brassicas are biennials naturally, but we harvest them during their first year before they 'bolt' and flower. In their second year, they would produce seed pods and cross-pollinate with other brassicas up to half a mile away.

Gardening Terms

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

Compost Full Sun Mulch pH Transplant True Leaves

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