Lettuce

Basic Information

Seed Number

80

Seed Name

Lettuce

Variety

Iceberg

Category

Vegetable

Plant Family

Asteraceae

Plant Type

Crisphead lettuce (Lactuca sativa)

Planting Method

Direct Sow or Transplant

Seed Status

In Seed Bank

Created

2026-08-14 00:50:34

Updated

2026-08-19 15:35:29

Planting Information

Start Planting Date

Mar 10

Last Recommended Planting Date

Sep 1

Plantable Months

March, April, May, July, August, September

Indoor Start

Mar 10 – Apr 1

Direct Sow

Apr 1 – Aug 31

Transplant

Apr 15 – Sep 1

Indoor Start Weeks Before Frost

8 weeks

Transplant Weeks After Frost

Not recorded

Germination Days

3–10 days

Harvest/Maturity

Not recorded

Succession Planting

14 days

Growing Conditions

Ideal Soil Temperature

40-70°F; best below 70°F

Planting Depth

1/8 in

Plant Spacing

10-12 in

Row Spacing

12-18 in

Thin-To Spacing

10-12 in

Sun Requirements

Full sun to partial shade

Water Needs

About 1 in/week; maintain consistent shallow-root-zone moisture

Soil Preference

Fertile, moisture-retentive but well-drained soil rich in organic matter; approximately pH 6.0-7.0

Minimum Container Size

2-3 gal per head; 8-10 in deep

Plant Height

8-12 in

Perennial/Biennial Status

Annual

Container Friendly

Yes

Trellis/Support Needed

No

Frost Tolerant

Yes

Heat Tolerant

No

Drought Tolerant

No

Pollinator Friendly

No

Medicinal

No

Garden Uses

Companion Planting

Storage

Seed Source/Brand

MSU Extension; Detroit frost dates; Almanac Detroit

Packet Year

Not recorded

Quantity Notes

Not recorded

Purchase Date

Not recorded

Expiration Year

Not recorded

Storage Box

Not recorded

Container

Not recorded

Envelope

Not recorded

Row

Not recorded

Slot

Not recorded

Storage Notes

Not recorded

Notes

Original Planting Method: Direct sow or start indoors
Outdoor / Direct Sow / Transplant Window: Mar 25 – May 15; Aug 15 – Sep 10
Days to Harvest / Bloom: 30–60 days
Container Friendly: Yes, shallow containers
Medicinal / Herbal Use: Culinary
Succession / Reusable Notes: Use shade cloth in warm weather; fall planting is usually easier.
Zone 6B Notes: Can bolt in heat. Germination drops when soil is hot.
Companion Plants: Carrots, radish, onions, cucumbers, strawberries, calendula, nasturtiums
Avoid Planting Near / Watch Outs: Hot exposed beds in midsummer
Sources: MSU Extension: https://www.canr.msu.edu/resources/garden_planning_calendar | Detroit frost dates: https://www.ufseeds.com/vegetable-planting-calendar-detroit-michigan.html | Almanac Detroit: https://www.almanac.com/gardening/planting-calendar/MI/Detroit

[[RESEARCH ENRICHMENT START]]
Zone 6B: Iceberg lettuce is a cool-season crop. Grow primarily in spring and again from late summer into fall. Avoid relying on midsummer plantings because high soil temperatures inhibit germination and heat can prevent good head formation.
Germination: Lettuce can germinate at soil temperatures near 40°F but germination becomes poor above about 75°F. Seed should be covered only lightly.
Harvest: Harvest when heads are full, dense and firm before bolting or bitterness develops.
Seed Saving: Allow selected plants to bolt and flower. Lettuce is predominantly self-pollinating but some insect-mediated crossing can occur.
Special Care: The name Iceberg identifies the crisphead class rather than a uniquely specified cultivar, so variety-specific maturity is left null.
Research Source: Johnny's Selected Seeds — https://www.johnnyseeds.com/growers-library/vegetables/lettuce/lettuce-key-growing-information.html — iceberg transplant recommendation, cool-season growth, germination temperature, sowing depth and succession planting
Research Source: University of Minnesota Extension — https://extension.umn.edu/planting-and-growing-guides/planting-vegetable-garden — lettuce direct sowing in cool 40-50°F soil
[[RESEARCH ENRICHMENT END]]