Soil temperature in Cedar Rapids, Iowa

Soil temperature

84°F28.7°C

at 6cm — germination depth

Cooling over the next 11 days.

Too warm to seed — the soil is heat-stressed. Wait for it to cool.

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.

Soil temperature at 6cm for reliable germination. Sources onthe method page.
SpeciesSoil tempDays
Perennial ryegrass8°C5–10
Red / chewings fescue8–10°C10–14
Tall fescuelikely yours10–12°C10–14
Browntop bentColonial bentgrass10–12°C14–21
Smooth-stalked meadow grassKentucky bluegrasslikely yours12–13°C14–28

Soil temperature at 6cm in Cedar Rapids, Iowa is currently 28.7°C, and falling about 25.5°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. Too warm to seed — the soil is heat-stressed. Wait for it to cool.

7 of the next 10 days are good mowing days. The best weekend slot right now is Sunday 10am–1pm, on the basis that cool — 25°C.

The next recommended window in Cedar Rapids opens at 8am on Wednesday 2 September, because anything earlier is the hour your neighbours will remember. Underfoot, the ground reads as firm after 1mm rain over the last week.

See the full mowing forecast for Cedar Rapids

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 28.7°C cooling to 0.0°C

Tuesday 1 September: Good. No — heat stress, 32°C.

Tuesday 1 SeptemberConfident

No — heat stress, 32°C.

Good:Grass wetness
Grass dryno rain since Saturday
Good:Ground firmness
Ground firm1mm rain over the last week
Good:Growth
Growing steadilygrowth potential 0.38
Poor:Temperature
Heat stress32°C
Good:Wind
Wind light7 km/h

Limiting factor:temperature

Wednesday 2 September: Good. 8am–10am — growing slowly — growth potential 0.27

Wednesday 2 September · 8am–10amConfident

8am–10am — growing slowly — growth potential 0.27

Good:Grass wetness
Grass dryno rain since Saturday
Good:Ground firmness
Ground firm1mm rain over the last week
Marginal:Growth
Growing slowlygrowth potential 0.27
Poor:Temperature
Cool24°C
Good:Wind
Wind light11 km/h
Sociable hours
A bit early or late, but finestarts when it stops being antisocial

Limiting factor:growth

Thursday 3 September: Good. 8am–11am — growing slowly — growth potential 0.30

Thursday 3 September · 8am–11amConfident

8am–11am — growing slowly — growth potential 0.30

Good:Grass wetness
Grass dryno rain since Saturday
Good:Ground firmness
Ground firm1mm rain over the last week
Marginal:Growth
Growing slowlygrowth potential 0.30
Poor:Temperature
Cool24°C
Good:Wind
Wind light9 km/h
Sociable hours
A bit early or late, but finestarts when it stops being antisocial

Limiting factor:growth

Friday 4 September: Good. 2pm–3pm — growing steadily — growth potential 0.36

Friday 4 September · 2pm–3pmConfident

2pm–3pm — growing steadily — growth potential 0.36

Good:Grass wetness
Grass dryno rain since Saturday
Good:Ground firmness
Ground firm1mm rain over the last week
Good:Growth
Growing steadilygrowth potential 0.36
Poor:Temperature
Cool24°C
Good:Wind
Wind light7 km/h
Sociable hours
Fine by the neighbours

Limiting factor:growth

Saturday 5 September: Good. 8am–11am — growing slowly — growth potential 0.33

Saturday 5 September · 8am–11amReasonably confident

8am–11am — growing slowly — growth potential 0.33

Good:Grass wetness
Grass dryno rain since Saturday
Good:Ground firmness
Ground firm1mm rain over the last week
Marginal:Growth
Growing slowlygrowth potential 0.33
Poor:Temperature
Cool25°C
Good:Wind
Wind light13 km/h
Sociable hours
A bit early or late, but finestarts when it stops being antisocial

Limiting factor:growth

Sunday 6 September: Good. 10am–1pm — cool — 25°C

Sunday 6 September · 10am–1pmReasonably confident

10am–1pm — cool — 25°C

Good:Grass wetness
Grass dryrain earlier today
Good:Ground firmness
Ground firm0mm rain over the last week
Good:Growth
Growing wellgrowth potential 0.67
Marginal:Temperature
Temperature20°C
Good:Wind
Wind light11 km/h
Sociable hours
Fine by the neighboursstarts when it stops being antisocial

Limiting factor:temperature

Monday 7 September: Marginal. No — 0.4mm of rain falling.

Monday 7 SeptemberReasonably confident

No — 0.4mm of rain falling.

Poor:Grass wetness
Grass wetraining now
Good:Ground firmness
Ground firm0mm rain over the last week
Good:Growth
Growing wellgrowth potential 0.90
Good:Temperature
Temperature19°C
Good:Wind
Wind light10 km/h

Limiting factor:grass wetness

Tuesday 8 September: Good. 5pm–8pm — dried off since a shower 1 hour ago, ground firm

Tuesday 8 September · 5pm–8pmReasonably confident

5pm–8pm — dried off since a shower 1 hour ago, ground firm

Good:Grass wetness
Grass dryno rain since Monday
Good:Ground firmness
Ground firm5mm rain over the last week
Good:Growth
Growing wellgrowth potential 0.90
Good:Temperature
Temperature20°C
Good:Wind
Wind light10 km/h
Sociable hours
A bit early or late, but finestarts once the rain has passed

Limiting factor:none

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 firm6mm rain over the last week
Good:Growth
Growing wellgrowth potential 0.74
Marginal:Temperature
Temperature21°C
Good:Wind
Wind light8 km/h

Limiting factor:none

Thursday 10 September: Not worth it. No — ground frozen.

Thursday 10 SeptemberLow confidence this far out

No — ground frozen.

Good:Grass wetness
Grass dryno rain since Tuesday
Good:Ground firmness
Ground firm6mm rain over the last week
Good:Growth
Growing wellgrowth potential 0.93
Good:Temperature
Temperature12°C
Good:Wind
Wind light19 km/h

Limiting factor:none

Nearby

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