Cardiff, Wales
Mowing
When you can next cut it, and the best slot this weekend.
Best weekend slot
Tomorrow 8am–8pm
Verdict: Good
rain earlier today, ground firm
Next mow
Today 8am–9am
Verdict: Good
grass slightly damp — rain 1 hour ago
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.
9°C — seeding
Soil at 6cm 18.1°C cooling to 15.7°C
Friday 4 September: Good. 11am–8pm — dried off since a shower 1 hour ago, ground firm
Friday 4 September · 11am–8pmConfident
11am–8pm — dried off since a shower 1 hour ago, ground firm
- Good:Grass wetness
- Grass drydried off since a shower 1 hour ago
- Good:Ground firmness
- Ground firm29mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 0.94
- Good:Temperature
- Temperature17°C
- Good:Wind
- Wind light18 km/h
- Sociable hours
- Fine by the neighboursstarts once the rain has passed
Limiting factor:none
Saturday 5 September: Good. 8am–8pm — rain earlier today, ground firm
Saturday 5 September · 8am–8pmConfident
8am–8pm — rain earlier today, ground firm
- Good:Grass wetness
- Grass dryrain earlier today
- Good:Ground firmness
- Ground firm29mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 0.81
- Good:Temperature
- Temperature12°C
- Good:Wind
- Wind light4 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 Friday, ground firm
Sunday 6 September · 10am–8pmConfident
10am–8pm — no rain since Friday, ground firm
- Good:Grass wetness
- Grass dryno rain since Friday
- Good:Ground firmness
- Ground firm12mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 0.99
- Good:Temperature
- Temperature15°C
- Good:Wind
- Wind light9 km/h
- Sociable hours
- Fine by the neighboursstarts when it stops being antisocial
Limiting factor:none
Monday 7 September: Good. 11am–8pm — dried off since a shower 1 hour ago, ground firm
Monday 7 September · 11am–8pmConfident
11am–8pm — dried off since a shower 1 hour ago, ground firm
- Good:Grass wetness
- Grass dryrain earlier today
- Good:Ground firmness
- Ground firm10mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 0.89
- Good:Temperature
- Temperature18°C
- Good:Wind
- Wind light11 km/h
- Sociable hours
- Fine by the neighboursstarts once the rain has passed
Limiting factor:none
Tuesday 8 September: Good. 8am–8pm — grass dry — rain earlier today
Tuesday 8 September · 8am–8pmReasonably confident
8am–8pm — grass dry — rain earlier today
- Good:Grass wetness
- Grass dryrain earlier today
- Good:Ground firmness
- Ground firm8mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 0.67
- Good:Temperature
- Temperature12°C
- Good:Wind
- Wind light9 km/h
- Sociable hours
- A bit early or late, but finestarts once the dew has burnt off
Limiting factor:grass wetness
Wednesday 9 September: Good. 8am–8pm — no rain since Tuesday, ground firm
Wednesday 9 September · 8am–8pmReasonably confident
8am–8pm — no rain since Tuesday, ground firm
- Good:Grass wetness
- Grass dryno rain since Tuesday
- Good:Ground firmness
- Ground firm8mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 0.65
- Good:Temperature
- Temperature12°C
- Good:Wind
- Wind light16 km/h
- Sociable hours
- A bit early or late, but finestarts when it stops being antisocial
Limiting factor:none
Thursday 10 September: Good. 8am–8pm — no rain since Tuesday, ground firm
Thursday 10 September · 8am–8pmReasonably confident
8am–8pm — no rain since Tuesday, ground firm
- Good:Grass wetness
- Grass dryno rain since Tuesday
- Good:Ground firmness
- Ground firm6mm rain over the last week
- Good:Growth
- Growing steadilygrowth potential 0.49
- Good:Temperature
- Temperature11°C
- Good:Wind
- Wind light3 km/h
- Sociable hours
- A bit early or late, but finestarts when it stops being antisocial
Limiting factor:none
Friday 11 September: Good. 8am–8pm — no rain since Tuesday, ground firm
Friday 11 September · 8am–8pmReasonably confident
8am–8pm — no rain since Tuesday, ground firm
- Good:Grass wetness
- Grass dryno rain since Tuesday
- Good:Ground firmness
- Ground firm5mm rain over the last week
- Good:Growth
- Growing steadilygrowth potential 0.40
- Good:Temperature
- Temperature12°C
- Good:Wind
- Wind light6 km/h
- Sociable hours
- A bit early or late, but finestarts once the dew has burnt off
Limiting factor:none
Saturday 12 September: Not worth it. No — 1.8mm of rain falling.
Saturday 12 SeptemberLow confidence this far out
No — 1.8mm of rain falling.
- Marginal:Grass wetness
- Grass drydried off since a shower 0 hours ago
- Marginal:Ground firmness
- Ground soft in places4mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 0.75
- Good:Temperature
- Temperature15°C
- Good:Wind
- Wind light18 km/h
Limiting factor:grass wetness
Sunday 13 September: Not worth it. No — 0.1mm of rain falling.
Sunday 13 SeptemberLow confidence this far out
No — 0.1mm of rain falling.
- Good:Grass wetness
- Grass drydried off since a shower 0 hours ago
- Good:Ground firmness
- Ground firm17mm rain over the last week
- Good:Growth
- Growing wellgrowth potential 0.52
- Good:Temperature
- Temperature12°C
- Good:Wind
- Wind light11 km/h
Limiting factor:grass wetness
Growth
How fast it is growing, and when it will need cutting again.
0.94Growing 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 5.6mm a day. A lawn cut today would be ready for another in around 3 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 18.5°C at 6cm and holding above 9°C.
Seeding
Soil temperature at germination depth, and when the window opens.
Soil temperature
18.5°C65°F
at 6cm — germination depth
Cooling over the next 10 days.
Seeding conditions are open — soil is 18.5°C at 6cm and holding above 9°C.
Cross-checks against an independent estimate from air temperature (18.2°C), which agrees to within 0.3°C.
Almost every UK and Irish lawn is a ryegrass and fescue mix, whether it was sown or turfed. We assume that, and use9°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 ryegrasslikely yours | 8°C | 5–10 |
| Red / chewings fescuelikely yours | 8–10°C | 10–14 |
| Tall fescue | 10–12°C | 10–14 |
| Browntop bentColonial bentgrass | 10–12°C | 14–21 |
| Smooth-stalked meadow grassKentucky bluegrass | 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.
Cardiff, Wales in detail
Soil temperature at 6cm in Cardiff, Wales is currently 18.5°C, and falling about 2.9°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 perennial ryegrass with fescue, which is what most lawns round here are sown with. That blend needs the soil to hold above 9°C before seed germinates reliably. Seeding conditions are open — soil is 18.5°C at 6cm and holding above 9°C.
8 of the next 10 days are good mowing days. The other 2 are held back by wet grass or soft ground. The best weekend slot right now is Tomorrow 8am–8pm, on the basis that rain earlier today, ground firm.
The next recommended window in Cardiff opens at 11am on Friday 4 September, because the rain clears by then. Underfoot, the ground reads as firm after 29mm 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.