Iceberg lettuce · Tianjin, Tianjin, China
When to plant iceberg lettuce in Tianjin
Main outdoor window
17-31 Mar
The window this page is built around.
Timed from last spring frost
7 April
In Tianjin, on your chosen risk.
Ready to pick
1 Jun - 30 Sep
If you plant at the start of the window.
The average last frost. Half of all years are later than this.
Step by step in Tianjin
Each window is a range, not a single day. Earlier in the range buys you a longer season; later in it buys you a safer one.
Start indoors
24 Feb - 10 Mar
Six weeks before your last frost, under cover or on a windowsill.
Sow direct
17-31 Mar
Three weeks before your last frost.
Transplant
24 Mar - 7 Apr
Two weeks before your last frost.
Harvest
1 Jun - 30 Sep
Iceberg lettuce through the year
Against the frost risk in Tianjin
Why these dates
Start indoors six weeks before the last frost and plant out two weeks before. A check to growth at any point gives you a loose head rather than a dense one.
Takes around -3C. The long season means a late sowing can be caught by the first autumn frost before it has hearted.
Seed packets and extension guides express timing as weeks either side of the last spring frost, because that is the only reference point that travels. Iceberg lettuce are timed from 6 weeks before that frost for an indoor start, with planting out 2 weeks before it, and this page simply resolves those offsets against the frost date computed for Tianjin.
The median frost-free season here is 207 days, against 70 to 85 days to maturity for this crop counted from sowing. That margin is what decides whether a late sowing is worth attempting.
Also in Tianjin
Other vegetables to time
Growing iceberg lettuce in Tianjin
When should I plant iceberg lettuce in Tianjin?
Aim for 17-31 Mar in an average year. If you would rather not gamble on the weather, wait until 23 Mar - 6 Apr - by then frost has finished in nine years out of ten.
When will iceberg lettuce be ready to harvest in Tianjin?
Expect to start picking around 1 Jun - 30 Sep, based on 70 to 85 days to maturity from the planting date calculated for this location.
How much frost will iceberg lettuce tolerate?
Takes around -3C. The long season means a late sowing can be caught by the first autumn frost before it has hearted.