Safe to Plant

Cos lettuce · Zigong, Sichuan, China

When to plant cos lettuce in Zigong

Main outdoor window

13-27 Jan

The window this page is built around.

Timed from last spring frost

3 February

In Zigong, on your chosen risk.

Ready to pick

1 May - 31 Oct

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 Zigong

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

23 Dec - 6 Jan

Six weeks before your last frost, under cover or on a windowsill.

Sow for autumn

4-25 Sep

Counting back 84 days from your first frost so the crop matures in time.

Sow direct

13-27 Jan

Three weeks before your last frost.

Sow direct

20 Jan - 3 Feb

Two weeks before your last frost.

Harvest

1 May - 31 Oct

Sow in succession. A single sowing gives you a single glut. Sow a short row every 10 days through the window above and you get a steady supply instead.
Frost tolerance
Half-hardy
Damaged below
-3°C (26.6°F)
Days to maturity
55–70
Min soil temp
4.5°C (40.1°F)
Spacing
25 cm
Sowing depth
6 mm (0.2 in)
Sun
Partial

Cos lettuce through the year

Against the frost risk in Zigong

Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Cos lettuce

Frost risk Start indoors Autumn sowing Sow direct Plant out Harvest Today

Why these dates

Sow every ten days from six weeks before the last frost. The upright habit means it can go closer together than a heading type without rotting in the middle.

Takes about -3C. Outer leaves mark after a frost but the heart is usually untouched and can simply be trimmed to.

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. Cos 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 Zigong.

The median frost-free season here is 318 days, against 55 to 70 days to maturity for this crop counted from sowing. That margin is what decides whether a late sowing is worth attempting.

See every crop timed for Zigong →

Nearby

Cos lettuce in places close by

Neijiang 39 km Yibin 66 km Luzhou 81 km Ziyang 88 km Leshan 101 km Meishan 120 km

Also in Zigong

Other vegetables to time

Tomatoes tender Lettuce half hardy Potatoes half hardy Courgettes tender Sweet peppers tender Carrots hardy Cucumbers tender Green beans tender Peas hardy Garlic very hardy Chilli peppers tender Sweetcorn tender

Growing cos lettuce in Zigong

When should I plant cos lettuce in Zigong?

Aim for 13-27 Jan in an average year. If you would rather not gamble on the weather, wait until 31 Jan - 14 Feb - by then frost has finished in nine years out of ten.

When will cos lettuce be ready to harvest in Zigong?

Expect to start picking around 1 May - 31 Oct, based on 55 to 70 days to maturity from the planting date calculated for this location.

How much frost will cos lettuce tolerate?

Takes about -3C. Outer leaves mark after a frost but the heart is usually untouched and can simply be trimmed to.