Crisphead & Iceberg
Lactuca sativa var. capitata
The hardest lettuce to grow well and the only one that keeps for three weeks.

It needs a long cool run
Crisphead takes seventy to ninety days and wants the whole of it below about 75F. In zone 6b/7 that is a narrow window. The reliable approach is to start indoors in late winter and transplant very early for a spring crop, or start in July for an autumn one - a mid-spring sowing almost always runs into heat before heading.
Heat gives you no head at all
Warm weather during head formation produces a loose, leafy, bitter plant that never firms up, or bolts straight through. This is the single reason most home crisphead attempts fail, and no amount of watering fixes it.
Transplant, do not direct sow
Because the timing is tight, start indoors four to six weeks ahead and set out well-hardened plants. Space twelve to fourteen inches - crispheads need more room than any other lettuce and crowding prevents heading.
Even water is critical
Any check causes tipburn, the brown crisped inner-leaf margins that ruin a head from the inside. Deep consistent watering and a thick mulch to keep the soil cool are essential, not optional.
Feed steadily
Rich soil and light regular nitrogen keep growth continuous. Slow growth gives small loose heads.
Modern alternatives
Batavian or summer crisp types (Nevada, Cherokee, Concept) give much of the crunch with far better heat tolerance and are considerably easier. If you want crisp lettuce in summer rather than iceberg specifically, grow those instead.
Pests and disease
Slugs, aphids buried deep in the head, bottom rot where the head meets wet soil, and downy mildew. The dense head means anything that gets inside is difficult to deal with.
Harvest and storage
Squeeze the head - it should feel firm and solid. Cut at the base, discarding the outer wrapper leaves. The payoff for the difficulty is storage: a good crisphead keeps two to three weeks refrigerated, far longer than any other lettuce.
- Days to harvest
- 70-90
- Spacing
- 12-14 in
- Row spacing
- 18-24 in
- Sun
- Full
- pH
- 6.0-7.0
- Needs
- Long cool run
- Difficulty
- High
- Storage
- 2-3 weeks