How to Grow Glacial Lettuce
Glacial Lettuce
Lactuca sativa var. crispa
vegetableGlacial is a crisp-head lettuce variety known for its exceptional cold hardiness and ability to withstand freezing temperatures while remaining tender and sweet. This heirloom variety produces dense, pale green heads with a delicate, buttery texture ideal for fresh salads. It's particularly valued in cool-season gardening for its reliability and superior flavor.
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Example Glacial Lettuce timeline · Pittsburgh, PA (Zone 6b)
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Plant Glacial Lettuce
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 Glacial Lettuce
Around Jun 11≈ 55 days after planting
Sample dates for Pittsburgh, PA. Sign up to get exact Glacial Lettuce dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 2-8; exceptionally cold-hardy for zones 2-5
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Seedling
7-10 daysFirst true leaves emerge; plant is 1-2 inches tall with 2-4 leaves
Keep soil consistently moist. Provide bright light if indoors. Thin seedlings to proper spacing once they have 2-3 true leaves. Protect from temperature fluctuations.
Vegetative Growth
15-25 daysPlant develops 6-12 leaves; forms loose rosette structure, beginning to expand outward
Maintain consistent soil moisture and cool temperatures (55-65°F ideal). Begin fertilizing every 2 weeks with diluted balanced fertilizer. Thin to final spacing if needed.
Head Formation
15-25 daysLeaves begin curling inward and compacting; head becomes denser and more defined
Continue regular watering and fertilizing. Ensure adequate spacing for air circulation. Monitor for bolting if temperatures exceed 70°F. Provide afternoon shade in warm regions.
Maturity
Ready to harvest; holds quality 10-14 daysHead is fully formed, dense, pale green, and compact with a crisp texture
Head remains harvestable for 1-2 weeks. Continue watering to maintain crispness. Cold hardy variety can tolerate light frosts. Harvest before any bolting occurs.
Post-Harvest
Variable; begins 2-4 weeks after maturityIf left unharvested, plant will bolt and flower, sending up a tall flowering stem
Once bolting begins, harvest quality declines. Remove bolted plant to make room for succession plantings. In cool climates, Glacial may produce seed before bolting.
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Spray with neem oil or insecticidal soap. Introduce ladybugs or lacewings. Remove affected leaves.
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Hand-pick at dawn/dusk. Use copper tape or diatomaceous earth barriers. Create hiding spots away from beds. Beer traps.
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Control aphids (vectors). Plant resistant varieties. Remove infected plants immediately. Sanitize tools.
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Improve air circulation. Water at soil level only. Apply sulfur dust if needed. Remove lower infected leaves.
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Cutworm collars around seedlings. Remove debris. Encourage ground beetles. Bacillus thuringiensis (Bt) applications.
Uses
Fresh Salads & Greens
CulinaryGlacial's tender, sweet leaves and crisp texture make it ideal for fresh salads, crunchy side dishes, and sandwich bases. The pale green color and delicate flavor complement light vinaigrettes and fresh herbaceous dressings. [source]
Cold-Hardy Harvest Extension
CulinaryUnlike many lettuce varieties, Glacial remains tender and edible through light freezes, allowing gardeners in northern climates to extend the harvest season well into fall and early winter without protection. [source]
Indoor Microgreens
HouseholdGlacial seeds can be sprouted indoors as microgreens in 10-14 days, providing nutrient-dense, tender greens year-round from a sunny windowsill with minimal space. [source]
Nutritional Support
MedicinalLettuce is rich in folate, vitamins A, C, and K, and contains compounds that may support heart health and provide mild sedative properties from lactucarium. [source]
Pollinator & Insect Support
WildlifeIf left to flower, Glacial produces small yellow flowers attractive to bees and beneficial insects, while flowering lettuce can be allowed to seed for wild pollinators. [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 head is fully formed and feels firm but yields slightly to gentle pressure. Cut at the base with a sharp knife, or pull entire plant with roots. Best harvested in early morning when leaves are crisp and full of moisture. In cool climates, Glacial can be harvested even after light frosts (28-32°F), enhancing sweetness. For cut-and-come-again harvesting, remove outer leaves while head continues growing.
Fun Facts
- 🌱 Glacial is an heirloom variety from Northern Europe, specifically bred for its exceptional ability to survive freezing temperatures while maintaining tender texture and sweet flavor—a trait that makes it nearly unique among crisp-head lettuces.
- 🌱 The name 'Glacial' refers to both the plant's cold hardiness and its pale, almost icy-looking pale green color, which is characteristic of the variety.
- 🌱 Lettuce contains a mild compound called lactucarium, historically called 'lettuce opium,' which was believed by ancient Greeks and Romans to have calming and sleep-inducing properties.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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