How to Grow Iceberg Lettuce 'Great Lakes'

Iceberg Lettuce 'Great Lakes'

Iceberg Lettuce 'Great Lakes'

Lactuca sativa var. capitata

vegetable

Great Lakes is a classic crisphead lettuce variety known for forming dense, compact heads with crisp, pale green leaves and a tender interior. This heirloom cultivar is reliable, cold-tolerant, and produces uniform heads ideal for storage and shipping. It's a staple variety prized for its excellent texture and mild flavor.

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Growing Conditions

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Sun: Full sun, 6-8 hours daily; afternoon shade beneficial in hot climates
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Water: Consistent moisture; keep soil evenly moist but not waterlogged. Water deeply 1-2 times weekly depending on temperature. Inconsistent watering can cause tip burn and poor head formation. Drip irrigation preferred to avoid wetting foliage.
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Spacing: 10-12 inches
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Days to maturity: 70-90 days from seed; 50-60 days from transplant
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Planting depth: 0.25-0.5 inches; seeds should be barely covered

Soil

Type: Well-draining, fertile loamy soil rich in organic matter
pH: 6.0-7.0
Amendments:
Compost Well-rotted manure Peat moss or coconut coir Balanced fertilizer (10-10-10)

Growing Zones

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Thrives in zones 3-9; prefers cool seasons, best grown in spring and fall

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

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Growth Stages

1

Germination & Seedling

7-14 days to germination, 2-3 weeks to first true leaves

Tiny seedlings emerge with cotyledons (seed leaves). First true leaves appear within 1-2 weeks, delicate and light green.

Keep soil consistently moist but not saturated. Provide bright light (seedling heat mats not necessary). Thin seedlings to proper spacing once first true leaves appear. Maintain temperatures 60-70°F.

2

Vegetative Growth

3-4 weeks

Plant develops 4-6 true leaves and begins forming a loose rosette. Foliage is bright green and rapidly expanding.

Maintain consistent watering and adequate light (6-8 hours). Begin fertilizing with diluted liquid fertilizer every 2 weeks or use slow-release granules. Thin to proper spacing (10-12 inches) if not done earlier. Monitor for early pest activity.

3

Head Formation

3-4 weeks

Outer leaves begin curling inward; the plant transitions from open rosette to compact head. Center leaves remain pale and tender.

Maintain consistent moisture to prevent tip burn and bolting. Keep soil temperature cool (below 70°F ideal). Continue light fertilizing if needed. Ensure adequate spacing to allow air circulation. Avoid overhead watering.

4

Head Maturation

2-3 weeks

Head becomes dense and firm with pale, crispy inner leaves. Outer leaves dark green, inner leaves white to pale yellow-green.

Reduce nitrogen fertilization to prevent excessive leafiness. Maintain steady watering. Head is ready when it feels firm to gentle pressure but before it gets too dense (which signals imminent bolting).

5

Harvest Readiness

Ready at 50-60 days from transplant or 70-90 days from seed

Head is fully formed, dense, and crisp. Leaves are firm and turgid. Plant may show signs of bolting initiation (center leaves tightening excessively or elongating).

Harvest promptly when head reaches desired size to prevent bolting, especially in warm weather. Early morning harvest yields crispest heads. Store harvested heads in cold conditions (32-35°F, 95% humidity) for extended shelf life.

Common Pests

  • Spray with water to dislodge; use neem oil or insecticidal soap. Encourage beneficial insects like ladybugs. Use row covers on seedlings.

  • and

    Hand-pick, especially at dawn and dusk. Create copper barriers around plants. Use diatomaceous earth. Beer traps or iron phosphate baits effective.

  • Use resistant varieties when possible. Rotate crops. Remove affected plants. Apply neem oil to soil surface.

  • Hand-pick caterpillars. Use Bacillus thuringiensis (Bt). Apply neem oil. Use row covers to prevent moth egg-laying.

  • Use reflective mulches. Spray with insecticidal soap or neem oil. Vacuum with handheld devices. Encourage beneficial insects.

Uses

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Fresh salads and crisp preparations

Culinary

Great Lakes lettuce is the classic choice for wedge salads and chopped salads due to its excellent crispness and structural integrity. The pale interior leaves are tender and mild, perfect for delicate dressings. [source]

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Sandwich and burger base

Culinary

The firm head structure and large leaves make this variety ideal for sandwich builders and burger accompaniments. Leaves hold up well to dressing and toppings without wilting quickly. [source]

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Commercial food service standard

Household

Great Lakes' uniform head size, excellent storability, and reliable production made it the standard iceberg variety for restaurants, grocery stores, and institutional food service for decades. [source]

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Nutritional content and vitamins

Culinary

Like all lettuces, Great Lakes provides vitamins K and A, folate, and beneficial fiber with very low calories. The tender inner leaves contain beneficial phytonutrients. [source]

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Seed saving heritage variety

Craft

As an heirloom variety introduced in the 1940s, Great Lakes is open-pollinated and amenable to home seed saving. It allows gardeners to preserve genetic diversity and adapt the variety to local conditions. [source]

Harvest Tips

Harvest when head feels firm but not rock-hard, typically 50-60 days after transplanting or 70-90 days from seed. Harvest in early morning for maximum crispness and water content. Cut heads at soil level with a sharp knife or pull entire plant. For continuous harvest, some growers cut outer leaves while leaving inner head to continue growing (though Great Lakes is primarily harvested as whole heads). Store in refrigerator crisper drawer at 32-35°F for 2-3 weeks. Harvest before daytime temperatures consistently exceed 75°F, as prolonged heat causes bolting and bitter taste.

Fun Facts

  • 🌱 Great Lakes was introduced in 1942 by the University of Wisconsin and became one of the most widely grown crisphead lettuce varieties in North America, particularly valued for its cold tolerance and ability to overwinter in mild climates.
  • 🌱 Despite being called 'iceberg' lettuce, the variety gets its name from the appearance of heads loaded on trucks packed with ice for transport in the early 20th century, not from the variety 'Great Lakes' specifically, which is simply one of the classic crisphead types.
  • 🌱 Great Lakes lettuce was selected for compact, dense head formation through generations of breeding, but this same density can sometimes lead to tip burn (browning of leaf edges) if calcium uptake is disrupted by inconsistent watering—a common problem gardeners encounter.

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