Soil temperature in Ottawa, Ontario
Soil temperature
20.7°C69°F
at 6cm — germination depth
Cooling over the next 11 days.
Seeding conditions are open — soil is 20.7°C at 6cm and holding above 12.5°C.
Most cool-season lawns in the northern US and Canada are bluegrass, tall fescue, or a mix of the two. We assume that, and use12.5°C as the seeding threshold.
I know what grass I have
The differences are small. Ryegrass is the quickest off the mark; bluegrass is the slowest and wants the warmest soil. Everything else sits between.
| Species | Soil temp | Days |
|---|---|---|
| Perennial ryegrass | 8°C | 5–10 |
| Red / chewings fescue | 8–10°C | 10–14 |
| Tall fescuelikely yours | 10–12°C | 10–14 |
| Browntop bentColonial bentgrass | 10–12°C | 14–21 |
| Smooth-stalked meadow grassKentucky bluegrasslikely yours | 12–13°C | 14–28 |
Soil temperature at 6cm in Ottawa, Ontario is currently 20.7°C, and falling about 19.1°C over the next 11 days. That depth matters because it is where grass seed sits and where roots start working, and it lags air temperature by days — which is why a warm afternoon here tells you very little on its own.
Lawns in this area are typically Kentucky bluegrass with tall fescue, the usual mix for cool-season lawns at this latitude. That blend needs the soil to hold above 12.5°C before seed germinates reliably. Seeding conditions are open — soil is 20.7°C at 6cm and holding above 12.5°C.
7 of the next 10 days are good mowing days. The other 3 are held back by wet grass or soft ground. The best weekend slot right now is Saturday 1pm–5pm, on the basis that ground soft in places — 16mm rain over the last week.
The next recommended window in Ottawa opens at 8am on Wednesday 2 September, because anything earlier is the hour your neighbours will remember. Underfoot, the ground reads as soft in places after 3mm rain over the last week.
The next 10 days
Column height is how mowable the day is; the lighter band is the best stretch within it. The line is soil temperature at 6cm. It crosses the seeding threshold inside this forecast.
12.5°C — seeding
Soil at 6cm 19.9°C cooling to 0.0°C
Tuesday 1 September: Not worth it. No — ground soft in places, 3mm rain over the last week.
Tuesday 1 SeptemberConfident
No — ground soft in places, 3mm rain over the last week.
- Good:Grass wetness
- Grass dryrain earlier today
- Marginal:Ground firmness
- Ground soft in places3mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 1.00
- Good:Temperature
- Temperature20°C
- Good:Wind
- Wind light7 km/h
Limiting factor:ground firmness
Wednesday 2 September: Good. 8am–4pm — ground soft in places — 8mm rain over the last week
Wednesday 2 September · 8am–4pmConfident
8am–4pm — ground soft in places — 8mm rain over the last week
- Good:Grass wetness
- Grass dryrain earlier today
- Marginal:Ground firmness
- Ground soft in places8mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 1.00
- Good:Temperature
- Temperature16°C
- Good:Wind
- Wind light5 km/h
- Sociable hours
- A bit early or late, but finestarts when it stops being antisocial
Limiting factor:ground firmness
Thursday 3 September: Good. 1pm–8pm — ground soft in places — 8mm rain over the last week
Thursday 3 September · 1pm–8pmConfident
1pm–8pm — ground soft in places — 8mm rain over the last week
- Marginal:Grass wetness
- Grass dryrain earlier today
- Marginal:Ground firmness
- Ground soft in places8mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 0.98
- Good:Temperature
- Temperature18°C
- Good:Wind
- Wind light11 km/h
- Sociable hours
- Fine by the neighboursstarts once the dew has burnt off
Limiting factor:ground firmness
Friday 4 September: Good. 1pm–8pm — ground soft in places — 16mm rain over the last week
Friday 4 September · 1pm–8pmConfident
1pm–8pm — ground soft in places — 16mm rain over the last week
- Good:Grass wetness
- Grass dryno rain since Thursday
- Marginal:Ground firmness
- Ground soft in places16mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 0.94
- Good:Temperature
- Temperature15°C
- Good:Wind
- Wind light8 km/h
- Sociable hours
- Fine by the neighboursstarts once the rain has passed
Limiting factor:ground firmness
Saturday 5 September: Good. 1pm–5pm — ground soft in places — 16mm rain over the last week
Saturday 5 September · 1pm–5pmReasonably confident
1pm–5pm — ground soft in places — 16mm rain over the last week
- Good:Grass wetness
- Grass dryrain earlier today
- Marginal:Ground firmness
- Ground soft in places16mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 0.84
- Good:Temperature
- Temperature16°C
- Good:Wind
- Wind light11 km/h
- Sociable hours
- Fine by the neighboursstarts once the rain has passed
Limiting factor:ground firmness
Sunday 6 September: Good. 10am–8pm — ground soft in places — 17mm rain over the last week
Sunday 6 September · 10am–8pmReasonably confident
10am–8pm — ground soft in places — 17mm rain over the last week
- Good:Grass wetness
- Grass dryrain earlier today
- Marginal:Ground firmness
- Ground soft in places17mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 0.82
- Good:Temperature
- Temperature11°C
- Good:Wind
- Wind light6 km/h
- Sociable hours
- Fine by the neighboursstarts when it stops being antisocial
Limiting factor:ground firmness
Monday 7 September: Good. 8am–8pm — ground soft in places — 16mm rain over the last week
Monday 7 September · 8am–8pmReasonably confident
8am–8pm — ground soft in places — 16mm rain over the last week
- Good:Grass wetness
- Grass dryno rain since Saturday
- Marginal:Ground firmness
- Ground soft in places16mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 0.91
- Good:Temperature
- Temperature13°C
- Good:Wind
- Wind light4 km/h
- Sociable hours
- A bit early or late, but finestarts when it stops being antisocial
Limiting factor:ground firmness
Tuesday 8 September: Good. 9am–8pm — ground soft in places — 16mm rain over the last week
Tuesday 8 September · 9am–8pmReasonably confident
9am–8pm — ground soft in places — 16mm rain over the last week
- Good:Grass wetness
- Grass drydried off since a shower 0 hours ago
- Good:Ground firmness
- Ground soft in places16mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 0.62
- Good:Temperature
- Temperature11°C
- Good:Wind
- Wind light18 km/h
- Sociable hours
- A bit early or late, but finestarts once the rain has passed
Limiting factor:ground firmness
Wednesday 9 September: Not worth it. No — ground frozen.
Wednesday 9 SeptemberLow confidence this far out
No — ground frozen.
- Good:Grass wetness
- Grass dryrain earlier today
- Good:Ground firmness
- Ground firm11mm rain over the last week
- Marginal:Growth
- Growing slowlygrowth potential 0.27
- Good:Temperature
- Temperature11°C
- Good:Wind
- Wind light6 km/h
Limiting factor:growth
Thursday 10 September: Not worth it. No — ground frozen.
Thursday 10 SeptemberLow confidence this far out
No — ground frozen.
- Poor:Grass wetness
- Grass wetraining now
- Good:Ground firmness
- Ground firm11mm rain over the last week
- Poor:Growth
- Barely growinggrowth potential 0.20
- Good:Temperature
- Temperature10°C
- Good:Wind
- Wind light15 km/h
Limiting factor:grass wetness
Nearby
Your own postcode
These are town-centre figures. Yours will differ a little.