Lactuca sativa var. capitata
Iceberg lettuce, crisp lettuce, American head lettuce: its name comes from railway transport in the 1920s, when Californian railcars shipped it under heaps of crushed ice — railway workers said they saw “icebergs” arriving. Its dense head and exceptional crunch have made it the most widely cultivated lettuce in the world.
Characteristics:
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Very compact head: tightly packed, fleshy leaves forming a dense, firm ball.
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Unmatched crunch: no other lettuce holds up as well to the bite.
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Excellent storage: it stays crisp for several days in the refrigerator, unlike butterhead lettuces, which wilt.
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Good heat tolerance: more tolerant than most lettuces, though not completely unaffected.
Sowing advice:
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Exposure: full sun in spring and fall, partial shade in midsummer. It tolerates heat better than other lettuces, but spring and fall crops remain the safest.
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Soil: cool, loose, well-drained, and lightly amended with compost. The soil must remain consistently cool: even brief drying triggers bolting and causes bitterness.
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Method: sow barely covered, as the seeds need light to germinate. Stagger sowings from March to August, every two weeks. Caution: above 25 °C, lettuce seeds enter dormancy and will no longer germinate — sow in the shade or at the end of the day during very hot weather. See how to sow your seeds.
Planting advice:
- Transplant at 4 or 5 leaves, spacing plants 30 to 35 cm apart — it needs more room than other lettuces to form its head. Do not bury the crown, or it may rot.
Care advice:
- Water regularly at the base in the morning, without wetting the foliage. Mulch to maintain soil moisture.
- Lightly hoe between the rows.
Harvesting advice:
- Harvest when the head feels very firm in your hand, cutting it at ground level. A head left too long becomes soft at the center and bitter.
- Tip: it keeps remarkably well unwashed, wrapped in a damp cloth in the bottom of the refrigerator.
Beneficial associations:
Benefits for biodiversity:
- Allow one plant to bolt at the end of the season: its small yellow flowers attract hoverflies and solitary bees, and its seeds feed goldfinches.
- Its rapid growth helps keep the soil covered between two main crops.
Uses:
- Raw in salads, but especially in burgers, sandwiches, wraps, and tacos, where its crunch and firmness make all the difference. Shredded into a chiffonade, it also pairs very well with Asian dishes.
Harvesting your own seeds:
Allow a strong plant to bolt: it produces a tall flower stalk, followed by seeds with fluffy tufts, which should be harvested as they mature gradually. Tip for Iceberg lettuce: because its head is so dense, cut a cross into the top to help the flower stalk emerge. Since lettuce is self-pollinating, cross-pollination is rare. See how to save your seeds.
Our Commitment to Quality: at SemiSauvage - Permaculture, we grow and select our seeds with respect for all living things as our guiding principle. Based near the Auvergne Volcanoes, we choose open-pollinated, non-hybrid varieties, test them for germination rates, and carefully sort and package them without any chemical treatment. Our conviction: to restore gardeners’ ability to resow, year after year, seeds that truly belong to them.
The crunchiest lettuce, the one that holds up in a burger.
