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How to Grow Brassicas (Cole Crops)

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Brassicas (Cole Crops)

Brassica oleracea and relatives

vegetable

Brassicas are cool-season cruciferous vegetables including cabbage, kale, broccoli, cauliflower, and Brussels sprouts. They are nutrient-dense crops rich in vitamins C and K, sulfur compounds, and fiber. These plants thrive in cool weather and are staples in crop rotation systems worldwide.

Looking for a specific variety?

Napa Cabbage Red Acre Savoy Lacinato Kale Curly Kale Broccoli Raab

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Example Brassicas (Cole Crops) timeline · Pittsburgh, PA (Zone 6b)

  1. Plant Brassicas (Cole Crops)

    Around Apr 17

    Near Pittsburgh's average last spring frost.

  2. Tend & protect

    Late spring–summer

    Watering, feeding, and pest-watch reminders.

  3. Harvest Brassicas (Cole Crops)

    Around Jun 1

    ≈ 45 days after planting

Sample dates for Pittsburgh, PA. Sign up to get exact Brassicas (Cole Crops) dates for your own zip code.

Growing Conditions

☀️
Sun: Full sun, 6+ hours daily (afternoon shade beneficial in hot climates)
💧
Water: Consistent moisture: 1-1.5 inches weekly. Keep soil evenly moist but not waterlogged. Inconsistent watering causes splitting and bolting.
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Spacing: 12-18 inches apart (cabbage 12-15", kale 12-18", larger varieties up to 24") inches
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Days to maturity: 45-120 days depending on variety and season
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Planting depth: ¼ inch for seeds; transplants at soil line (same depth as container)

Soil

Type: Rich, well-draining loamy soil with high organic matter
pH: 6.0-7.5
Amendments:
Compost or aged manure (2-3 inches) Nitrogen-rich fertilizer (blood meal, fish emulsion) Boron (1-2 lbs per acre; deficiency causes hollow stem) Calcium (lime if pH below 6.0)

Growing Zones

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Zones 2-9; spring crops in cool climates, fall crops in warm climates

2a 2b 3a 3b 4a 4b 5a 5b 6a 6b 7a 7b 8a 8b 9a 9b 10a

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Growth Stages

1

Seedling

4-6 weeks

Cotyledons emerge, true leaves develop. Plant is small and delicate.

Start indoors 4-6 weeks before transplanting. Keep soil moist but not soggy. Provide 14-16 hours of light daily. Maintain 65-70°F for optimal growth.

2

Vegetative Growth

3-6 weeks after transplanting

Rosette of leaves expands rapidly. Plant develops strong root system and secondary leaves form.

Transplant when 4-6 true leaves present. Apply nitrogen-rich fertilizer every 2-3 weeks. Monitor for cabbage moths and flea beetles. Keep consistently watered.

3

Head/Leaf Development

4-8 weeks

For cabbage: leaves begin forming tight heads. For kale: mature leaf size reached with increasingly frilly or curled texture.

Reduce nitrogen slightly to promote head formation (over-nitrogen causes loose heads). Maintain consistent moisture to prevent splitting. Mulch to regulate soil temperature and retain moisture.

4

Maturity & Harvest-Ready

Variable; some mature and hold well for weeks

Cabbage heads feel firm when squeezed; kale leaves reach full size. Plant reaches marketable size.

Stop fertilizing 2-3 weeks before harvest. Monitor for late-season pests. Can leave many brassicas in ground for extended harvest (cold improves flavor).

5

Regrowth (Spring Plantings)

2-4 weeks for secondary harvest

After harvesting main head, secondary shoots emerge from leaf axils (especially kale, broccoli, cabbage).

Cut main head leaving 4-6 inches of stem. Apply balanced fertilizer to support regrowth. Secondary heads will mature in 3-4 weeks.

Companion Planting

Plan your garden →

Plant with:

Beets Onions Garlic Dill Celery Chamomile Mint Nasturtium Marigold Borage Potatoes Carrots Lettuce

Avoid planting near:

Tomatoes Peppers Fennel Kohlrabi Mustard Radish Turnip Other brassicas (same season; rotate to different bed) Strawberries Beans (some conflict)

Common Pests

  • Row covers over seedlings; hand-pick eggs/larvae; Bt (Bacillus thuringiensis) spray; companion plants like dill and marigold attract parasitoids

  • Bt spray; neem oil; hand-picking; encourage parasitic wasps with flowering plants

  • Row covers on young plants; kaolin clay spray; reflective mulches; neem oil; remove debris that harbors overwintering beetles

  • Bt; spinosad; row covers; crop rotation (move 2-3 garden beds away); remove crop residue

  • Rotate out of brassica family for 4-7 years; raise soil pH to 7.2+; select resistant varieties; solarize soil if possible; avoid spreading contaminated soil/tools

  • Use disease-free seed; avoid overhead watering; remove infected leaves; rotate crops; sanitize tools; resistant varieties

  • Strong water spray; insecticidal soap; neem oil; reflective mulches; encourage ladybugs and lacewings

Uses

🍳

Raw & Cooked Preparations

Culinary

Cabbage is eaten raw in slaws, fermented as sauerkraut or kimchi, steamed, sautéed, or braised. Kale appears in chips, salads, soups, smoothies, and stir-fries. Both are versatile across cuisines. [source]

💊

Glucosinolates & Cancer Prevention

Medicinal

Brassicas contain glucosinolates that break down into sulforaphane and indole-3-carbinol, compounds studied for anticarcinogenic properties. Kale and cabbage are among the most concentrated sources. [source]

🏠

Fermentation & Preservation

Household

Cabbage is ideal for lacto-fermentation to produce sauerkraut and kimchi, promoting beneficial probiotics and extending shelf life. These fermented products support digestive health. [source]

💊

Vitamin K & Bone Health

Medicinal

Kale contains 145% of daily value of vitamin K per cup, critical for bone mineralization and blood clotting. One serving supports skeletal health and cardiovascular function. [source]

🦋

Butterfly & Pollinator Crops

Wildlife

Flowering brassicas (when bolting) provide pollen and nectar to honeybees, bumblebees, and butterflies. Allowing some plants to flower extends habitat value beyond harvest season. [source]

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

Harvest Tips

Spring/early summer: Harvest when heads are firm (squeeze test). Fall crops: after frost improves sweetness; kale is best after light frost. Cut main head 1-2 inches above soil to allow secondary shoots. Morning harvest (after dew dries) for best flavor. For continuous harvest, pick outer leaves of kale instead of entire plant.

Fun Facts

  • 🌱 Brassicas have been selectively bred from the same wild species (Brassica oleracea) over millennia: cabbage, kale, broccoli, cauliflower, and Brussels sprouts are all the same species with different traits selected for (leaf, flower bud, or sprout development).
  • 🌱 Kale's flavor improves dramatically after frost because plants convert starches to sugars as a natural antifreeze, making fall-harvested kale sweeter than summer kale.
  • 🌱 In crop rotation, brassicas should not return to the same bed for 3-4 years (or 7+ years if clubroot is present) because soil-borne pathogens and depleted nutrients can reduce yields by 50-70%.

Gardening Terms

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

Bolt Full Sun Mulch Transplant True Leaves
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