Vegetable · Asteraceae

When to plant iceberg lettuce

Iceberg is a crisphead lettuce. Choose a cultivar for the local season and allow its full heading space rather than copying spacing intended for baby salad leaves.

Start seed indoors

6 weeks before

Counted from your last spring frost.

Plant out

2 weeks before

Counted from your last spring frost.

Sow direct

3 weeks before

Counted from your last spring frost.

Choose a place for estimated dates and local climate checks.

Timing, in frost-relative terms

These offsets are the starting assumptions used by our calendar for iceberg lettuce. They do not establish suitability in every climate. Your seed packet, cultivar and local growing advice take priority; in frost-free places the calendar uses monthly temperature patterns instead.

  • Start seed indoors 6 weeks before the last frost.
  • Plant out 2 weeks before the last frost.
  • Sow direct 3 weeks before the last frost.
  • Expect 70–85 days to maturity, counted from sowing.
  • Sow again every 14 days for a continuous supply.

Getting the timing right

Keep shallow roots consistently supplied with moisture. Repeated drying and hot weather can interrupt heading or bring bolting before a firm centre develops.

Frost tolerance

Protect tender growth from frost and wait for suitable growing warmth. The catalog cold-damage figure is a reference, not a guarantee: duration, wind, plant age and acclimatisation affect damage.

Classified as half-hardy, with a catalog cold-damage reference of -3°C (26.6°F). Exposure duration, growth stage and acclimatisation change cold tolerance.

How to use a frost date without treating it as a promise

Before you plant iceberg lettuce

Use the calendar to plan ahead, then check the conditions in your own garden.

  • Measure the soil at sowing depth. Aim for at least 4.5°C (40.1°F); the calendar estimates soil warmth from air temperatures and cannot measure your bed.
  • Check the local overnight forecast before planting out. Delay planting or keep protection ready if frost is forecast, even after the historical last-frost date.
  • Harden off plants raised indoors: gradually expose them to outdoor light, wind and temperature before their final move into the bed.
  • Use the maturity range on your seed packet when choosing a variety. Cold, short days and transplant stress can make harvest later than the calendar estimate.

Give crisphead lettuce an uninterrupted heading period

Keep shallow roots consistently supplied with moisture. Repeated drying and hot weather can interrupt heading or bring bolting before a firm centre develops.

Check the head as it approaches the cultivar's expected size and harvest while quality is good. Make staggered small plantings so several large heads do not all need using on the same day.

What to record this season

Did the head firm up before heat or drying interrupted growth? Add the cultivar, sowing date and conditions to your growing record so you can compare next season.

Further reading: RHS lettuce growing guide . General crop guidance; local dates on this site are calculated separately. Source checked 19 September 2026 by Safe to Plant; this is not an expert review.

The RHS guide is written for UK growing conditions. Use its cultivation advice with local cultivar and seasonal guidance; its calendar months are not worldwide recommendations.

How the dates are calculated and their limits · Keep a growing record · Report a local discrepancy

Local planting estimates

Iceberg lettuce in…

Shanghai China Beijing China Shenzhen China Guangzhou China Kinshasa Democratic Republic of the Congo Istanbul Turkey Lagos Nigeria Ho Chi Minh City Vietnam Chengdu China Lahore Pakistan Mumbai India São Paulo Brazil Mexico City Mexico Karachi Pakistan Tianjin China Delhi India Wuhan China Moscow Russia Dhaka Bangladesh Seoul South Korea Tokyo Japan Dongguan China Cairo Egypt Xi’an China Nanjing China Hangzhou China Foshan China London United Kingdom New York City United States Jakarta Indonesia