Tacoma, Washington
Mowing
When you can next cut it, and the best slot this weekend.
Best weekend slot
Saturday 8am–8pm
Verdict: Good
no rain since Thursday, ground firm
Next mow
Today 6pm–8pm
Verdict: Good
dried off since a shower 3 hours ago, ground firm
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 16.5°C cooling to 0.0°C
Wednesday 2 September: Good. 6pm–8pm — dried off since a shower 3 hours ago, ground firm
Wednesday 2 September · 6pm–8pmConfident
6pm–8pm — dried off since a shower 3 hours ago, ground firm
- Good:Grass wetness
- Grass drydried off since a shower 3 hours ago
- Good:Ground firmness
- Ground firm0mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 0.81
- Good:Temperature
- Temperature16°C
- Good:Wind
- Wind light13 km/h
- Sociable hours
- A bit early or late, but fine
Limiting factor:none
Thursday 3 September: Good. 8am–1pm — rain earlier today, ground firm
Thursday 3 September · 8am–1pmConfident
8am–1pm — rain earlier today, ground firm
- Good:Grass wetness
- Grass dryrain earlier today
- Good:Ground firmness
- Ground firm1mm rain over the last week
- Good:Growth
- Growing steadilygrowth potential 0.49
- Good:Temperature
- Temperature11°C
- Good:Wind
- Wind light5 km/h
- Sociable hours
- A bit early or late, but finestarts when it stops being antisocial
Limiting factor:none
Friday 4 September: Good. 3pm–8pm — grass dry — rain earlier today
Friday 4 September · 3pm–8pmConfident
3pm–8pm — grass dry — rain earlier today
- Poor:Grass wetness
- Grass dryrain earlier today
- Good:Ground firmness
- Ground firm2mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 0.58
- Good:Temperature
- Temperature11°C
- Good:Wind
- Wind light6 km/h
- Sociable hours
- Fine by the neighboursstarts once the dew has burnt off
Limiting factor:grass wetness
Saturday 5 September: Good. 8am–8pm — no rain since Thursday, ground firm
Saturday 5 September · 8am–8pmConfident
8am–8pm — no rain since Thursday, ground firm
- Good:Grass wetness
- Grass dryno rain since Thursday
- Good:Ground firmness
- Ground firm8mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 0.72
- Good:Temperature
- Temperature12°C
- Good:Wind
- Wind light1 km/h
- Sociable hours
- A bit early or late, but finestarts when it stops being antisocial
Limiting factor:none
Sunday 6 September: Good. 10am–8pm — no rain since Thursday, ground firm
Sunday 6 September · 10am–8pmReasonably confident
10am–8pm — no rain since Thursday, ground firm
- Good:Grass wetness
- Grass dryno rain since Thursday
- Good:Ground firmness
- Ground firm8mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 0.83
- Good:Temperature
- Temperature13°C
- Good:Wind
- Wind light10 km/h
- Sociable hours
- Fine by the neighboursstarts when it stops being antisocial
Limiting factor:none
Monday 7 September: Good. 10am–8pm — no rain since Thursday, ground firm
Monday 7 September · 10am–8pmReasonably confident
10am–8pm — no rain since Thursday, ground firm
- Good:Grass wetness
- Grass dryno rain since Thursday
- Good:Ground firmness
- Ground firm8mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 0.94
- Good:Temperature
- Temperature11°C
- Good:Wind
- Wind light1 km/h
- Sociable hours
- Fine by the neighboursstarts when it stops being antisocial
Limiting factor:none
Tuesday 8 September: Good. 8am–8pm — no rain since Thursday, ground firm
Tuesday 8 September · 8am–8pmReasonably confident
8am–8pm — no rain since Thursday, ground firm
- Good:Grass wetness
- Grass dryno rain since Thursday
- Good:Ground firmness
- Ground firm8mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 0.93
- Good:Temperature
- Temperature13°C
- Good:Wind
- Wind light2 km/h
- Sociable hours
- A bit early or late, but finestarts when it stops being antisocial
Limiting factor:none
Wednesday 9 September: Good. 8am–6pm — no rain since Thursday, ground firm
Wednesday 9 September · 8am–6pmReasonably confident
8am–6pm — no rain since Thursday, ground firm
- Good:Grass wetness
- Grass dryno rain since Thursday
- Good:Ground firmness
- Ground firm8mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 0.89
- Good:Temperature
- Temperature12°C
- Good:Wind
- Wind light1 km/h
- Sociable hours
- A bit early or late, but finestarts when it stops being antisocial
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 Thursday
- Good:Ground firmness
- Ground firm7mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 0.96
- Good:Temperature
- Temperature13°C
- Good:Wind
- Wind light2 km/h
Limiting factor:none
Friday 11 September: Not worth it. No — ground frozen.
Friday 11 SeptemberLow confidence this far out
No — ground frozen.
- Good:Grass wetness
- Grass dryno rain in over a week
- Good:Ground firmness
- Ground firm7mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 0.88
- Good:Temperature
- Temperature14°C
- Good:Wind
- Wind light7 km/h
Limiting factor:none
Growth
How fast it is growing, and when it will need cutting again.
0.81Growing strongly
Growth potential, 0 to 1 — the turf-industry measure of how fast grass can grow at today's temperature and day length.
Putting on about 4.8mm a day. A lawn cut today would be ready for another in around 4 days.
Worked out from the PACE Turf growth potential model and day length —how and why.
What this means right now
Good: Seeding window open
Seeding conditions are open — soil is 16.6°C at 6cm and holding above 12.5°C.
Warning: Heat stress
Monday 7 September gets hot enough to stress the sward. Mow early or late, and raise the height.
Seeding
Soil temperature at germination depth, and when the window opens.
Soil temperature
62°F16.6°C
at 6cm — germination depth
Cooling over the next 10 days.
Seeding conditions are open — soil is 16.6°C at 6cm and holding above 12.5°C.
Cross-checks against an independent estimate from air temperature (16.9°C), which agrees to within 0.8°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 |
Feeding
Why timing decides whether a feed does anything at all.
Coming in the app
Grass takes up nitrogen when it is growing. Feed a lawn that has stopped and most of it washes past the roots — which is why timing beats product choice.
Right now this lawn is growing well enough to use a feed.
The app will work out the actual feeding windows for your lawn — along with weed control, scarifying and moss treatment — and tell you when they open without you having to check.
Tacoma, Washington in detail
Soil temperature at 6cm in Tacoma, Washington is currently 16.6°C, and falling about 16.1°C over the next 10 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 16.6°C at 6cm and holding above 12.5°C.
8 of the next 10 days are good mowing days. The best weekend slot right now is Saturday 8am–8pm, on the basis that no rain since Thursday, ground firm.
The next recommended window in Tacoma opens at 6pm on Wednesday 2 September, and holds while conditions stay put. Underfoot, the ground reads as firm after 0mm rain over the last week.
Forecast from Open-Meteo, refreshed hourly. Soil temperature is modelled, not measured — how that works and where the thresholds come from.