Mowdar

Soil temperature

Grass seed responds to the soil around it, not the air above it, and not the month. Soil at 6cm — germination depth — lags air temperature by days and swings far less, which is why one warm afternoon means nothing.

Right now

UK & Ireland
18 places, as a table
PlaceSoil at 6cmSeeding
London16.6°COpen
Cardiff16.0°COpen
Bristol16.0°COpen
Norwich15.9°COpen
Exeter15.7°COpen
Dublin15.7°COpen
Liverpool15.2°COpen
Cork15.2°COpen
Newcastle upon Tyne15.1°COpen
Galway14.9°COpen
Leeds14.7°COpen
Manchester14.7°COpen
Belfast14.5°COpen
Birmingham14.3°COpen
Edinburgh14.0°COpen
Glasgow13.5°COpen
Inverness12.4°COpen
Aberdeen11.7°COpen
Northern US & Canada
15 places, as a table
PlaceSoil at 6cmSeeding
Chicago89°FClosed
Detroit84°FClosed
Denver84°FClosed
Minneapolis84°FClosed
Philadelphia82°FClosed
Pittsburgh81°FClosed
New York78°FOpen
Calgary77°FClosed
Toronto74°FOpen
Portland71°FOpen
Winnipeg71°FOpen
Montreal71°FOpen
Seattle68°FOpen
Boston66°FOpen
Halifax64°FOpen

Green is soil warm enough to seed the local grass mix;brown is still too cold. Bigger circles are warmer. These are modelled figures, not readings from a probe in the ground.

What temperature do you need?

UK & Ireland

9°C48°F

Almost every lawn here is a ryegrass and fescue mix. Once the soil holds above this for a few days, seed will take.

Northern US & Canada

12.5°C55°F

Bluegrass and tall fescue lawns want it warmer, and bluegrass is the slowest of the lot to get going.

If you do not know what you have, use the figure for your region — the whole spread between species is about four degrees, and waiting a few extra days costs nothing.

Species by species
SpeciesSoil at 6cmDays to germinate
Perennial ryegrass8°C (46–46°F)5–10
Red / chewings fescue8–10°C (46–50°F)10–14
Tall fescue10–12°C (50–54°F)10–14
Browntop bentColonial bentgrass10–12°C (50–54°F)14–21
Smooth-stalked meadow grassKentucky bluegrass12–13°C (54–55°F)14–28

Sources for every figure are on the method page.

By place

UK & Ireland

US & Canada