Safe to Plant

Cos lettuce · Korolev, Moscow Oblast, Russia

When to plant cos lettuce in Korolev

Main outdoor window

12-26 Apr

The window this page is built around.

Timed from last spring frost

3 May

In Korolev, 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 Korolev

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

22 Mar - 5 Apr

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

Sow for autumn

23 Jun - 14 Jul

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

Sow direct

12-26 Apr

Three weeks before your last frost.

Sow direct

19 Apr - 3 May

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 Korolev

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

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 Korolev.

The median frost-free season here is 157 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 Korolev →

Growing cos lettuce in Korolev

When should I plant cos lettuce in Korolev?

Aim for 12-26 Apr in an average year. If you would rather not gamble on the weather, wait until 27 Apr - 11 May - by then frost has finished in nine years out of ten.

When will cos lettuce be ready to harvest in Korolev?

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.