What hardiness zones is Lactuca sativa 'Great Lakes' suitable for?

Lactuca sativa 'Great Lakes' is a crisphead (iceberg-type) annual lettuce in the family Asteraceae forming a tight firm round head 8-12 inches (20-30 cm) tall and 12-16 inches (30-40 cm) wide. The cultivar produces bright green outer leaves with pale green to white crisp interior and thick prominent white midribs. Open-pollinated and an All-America Selections winner in 1944. Seeds can be saved. Crisphead type forms a tight firm head like commercial iceberg lettuce. Maturity is 75-90 days from seed, longer than butterhead or romaine types and a limitation for short-season gardens. Head formation requires consistent cool temperatures of 60-70°F (16-21°C) and the cultivar fails to head in warm climates. Bolts in sustained heat above 80°F (27°C). The cultivar is more bolt-resistant than many crisphead cultivars. Succession-sown every 2-3 weeks. Slugs and aphids are the primary pests. Not deer-resistant. Non-toxic edible crop. Annual with moderate growth rate.

Native Range

Lactuca sativa 'Great Lakes' is an open-pollinated cultivar; an All-America Selections winner in 1944. The species L. sativa is native to the Mediterranean region.

Suggested Uses

Grown in vegetable gardens, raised beds, and containers of at least 3 gallons (11 L) for culinary use: salads, sandwiches, wraps, and fresh eating. Crisphead (iceberg-type) lettuce. Open-pollinated heirloom and 1944 AAS winner. Succession-sown for continuous harvest. Non-toxic. Not deer-resistant. Annual. Maturity 75-90 days is longer than butterhead or romaine types. Not suited to warm summer climates without afternoon shade or to short-season gardens that cannot accommodate the 75-90 day cycle.

How to Identify

Identified by a tight firm round crisphead with bright green outer leaves and pale green to white crisp interior with prominent white midribs. Separated from butterhead types (loose soft head) and romaine types (upright elongated) by the tight firm round head formation. In family Asteraceae.

Appearance

Size & Dimensions

Height8" - 1'

Width/Spread1' - 1'4"

Reaches mature size in approximately 1 years

Colors

Flower Colors

yellow

Foliage Colors

green

Fall Foliage Colors

no change

Bloom Information

Bolts in sustained heat. Pale yellow composite flowers (daisy family) on bolting stalks. Bolting makes leaves bitter and plants are pulled when the bolting stalk appears.

Detailed Descriptions

Flower Description

Pale yellow; daisy-family composite; on bolting stalks only

Foliage Description

Bright green outer leaves with pale green to white crisphead interior; thick-ribbed with prominent white midribs; deciduous

Growing Conditions

Sun Requirements

Full Sun Partial Shade

Requires 4-8 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range6.0 - 7.0(Neutral)

357912

Soil Types

loam

Drainagemoist

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Time to Maturity

75-90 days from seed to mature head

Care & Maintenance

Care Guide

Part sun to full sun. Rich moist soil at pH 6.0-7.0. Cool-season crop and bolts above 80°F (27°C). Head formation requires 60-70°F (16-21°C). Succession-sown every 2-3 weeks. Open-pollinated and seeds can be saved (AAS 1944). Slugs and aphids are the primary pests. Not deer-resistant. Non-toxic. Annual.

Pruning

Harvest takes the entire head by cutting at the base when firm. Plants are pulled when the bolting stalk appears since leaves become bitter. Succession-sown every 2-3 weeks.