TR18, Cornwall

TR18, Cornwall50.1175, -5.5424from your postcode

Mowing

When you can next cut it, and the best slot this weekend.

Best weekend slot

Nothing doing

Verdict: Not worth it

ground waterlogged.

Tomorrow afternoon is your first decent window.

Next mow

Tomorrow 1pm–5pm

Verdict: Prime time

grass dry — dry since Monday by then

  • Worth watching: Ground still soft. 39mm rain over the last week, medium (loam) soil. A mower will mark it, and a ride-on will rut it. More

The next 10 days

Each row is a day, morning on the left. The more solid a block, the more of the forecast runs agree you can mow. Open a day for the hour-by-hour forecast behind it.

  1. Monday 19 October: no hours worth using. No — 2.7mm of rain falling.
    Monday 19 October, hour by hour
    5am6am7am8am9am10am11ammidday1pm2pm3pm4pm5pm6pm7pm8pm
    Chance————————————————
    VerdictAlready goneAlready goneAlready goneAlready goneAlready goneAlready goneAlready goneAlready goneAlready gone2.7mm of rain falling0.4mm of rain falling0.6mm of rain fallingForget itForget itdarkdark
    Rainchance·········———————
    Rainmm·········2.70.40.6————
    Grass·········soakedsoakedsoakedsoakedsoakedsoakedsoaked
    Ground·········firmfirmfirmfirmfirmfirmfirm
    Temp·········10°11°12°12°11°11°12°
    Windkm/h·········73176101014
    Daylight·········✓✓✓✓✓——

    Growth: barely growing (growth potential 0.12). Enough to be worth cutting. Growth decides whether a cut is wanted, not how well it will go, so it is not one of the rows above and does not move the chances.

    Monday 19 OctoberConfident

    No — 2.7mm of rain falling.

    Limiting factor:grass wetness

  2. Tuesday 20 October: 4 hours worth using. 1pm–5pm — grass dry — dry since Monday by then
    Tuesday 20 October, hour by hour
    5am6am7am8am9am10am11ammidday1pm2pm3pm4pm5pm6pm7pm8pm
    Chance————————————————
    VerdictdarkdarkdarkForget itForget itForget itForget itForget itPrime timePrime timePrime timePrime time0.7mm of rain falling0.5mm of rain fallingdarkdark
    Rainchance————————————————
    Rainmm————————————0.70.50.30.1
    Grasssoakedsoakedsoakedsoakedsoakedsoakedsoakedsoakeddampdampdrydrysoakedsoakedsoakedsoaked
    Groundfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirmfirm
    Temp7°7°7°7°9°11°13°14°14°14°14°14°13°12°12°12°
    Windkm/h34531112131515191911141724
    Daylight———✓✓✓✓✓✓✓✓✓✓✓——

    Growth: barely growing (growth potential 0.18). Enough to be worth cutting. Growth decides whether a cut is wanted, not how well it will go, so it is not one of the rows above and does not move the chances.

    Tuesday 20 October · 1pm–5pmConfident

    1pm–5pm — grass dry — dry since Monday by then

    Limiting factor:grass wetness

  3. Wednesday 21 October: 5 hours worth using. 1pm–5pm — grass dry — dry again 4 hours after a shower
    Wednesday 21 October, hour by hour
    5am6am7am8am9am10am11ammidday1pm2pm3pm4pm5pm6pm7pm8pm
    Chance————————————————
    Verdictdarkdarkdarkground waterloggedground waterloggedground waterloggedGood to go0.3mm of rain fallingPrime timePrime timePrime timePrime time0.2mm of rain falling0.2mm of rain fallingdarkdark
    Rainchance————————————————
    Rainmm———————0.30.1———0.20.20.20.5
    Grasssoakedsoakedwetwetdampdampdampdampdrydrydrydrydrydrydrysoaked
    Groundbogbogbogbogbogbogsoftsoftsoftsoftsoftfirmfirmfirmbogbog
    Temp11°11°10°11°11°11°11°11°12°12°12°12°12°11°11°11°
    Windkm/h40383939343345363433302825232119
    Daylight———✓✓✓✓✓✓✓✓✓✓✓——

    Growth: barely growing (growth potential 0.18). Enough to be worth cutting. Growth decides whether a cut is wanted, not how well it will go, so it is not one of the rows above and does not move the chances.

    Wednesday 21 October · best slot1pm–5pmConfident

    1pm–5pm — grass dry — dry again 4 hours after a shower

    Also mowable today: 11am–midday

    Limiting factor:grass wetness

  4. Thursday 22 October: no hours worth using. No — ground waterlogged.
    Thursday 22 October, hour by hour
    5am6am7am8am9am10am11ammidday1pm2pm3pm4pm5pm6pm7pm8pm
    Chance————————————————
    Verdictdarkdarkdarkground waterloggedground waterloggedground waterloggedground waterloggedground waterloggedground waterlogged0.9mm of rain falling0.9mm of rain falling0.9mm of rain falling3.6mm of rain falling3.6mm of rain fallingdarkdark
    Rainchance————————————————
    Rainmm—————————0.90.90.93.63.63.61.6
    Grasssoakedsoakedsoakedsoakedsoakedsoakedwetdrydrysoakedsoakedsoakedsoakedsoakedsoakedsoaked
    Groundbogbogbogbogbogbogbogbogbogbogbogbogbogbogbogbog
    Temp11°10°10°11°11°12°13°14°15°14°13°12°12°13°13°13°
    Windkm/h1715129769141922262935414546
    Daylight———✓✓✓✓✓✓✓✓✓✓✓——

    Growth: growing slowly (growth potential 0.24). Enough to be worth cutting. Growth decides whether a cut is wanted, not how well it will go, so it is not one of the rows above and does not move the chances.

    Thursday 22 OctoberConfident

    No — ground waterlogged.

    Limiting factor:grass wetness

  5. Friday 23 October: no hours worth using. No — 0.2mm of rain falling.
    Friday 23 October, hour by hour
    5am6am7am8am9am10am11ammidday1pm2pm3pm4pm5pm6pm7pm8pm
    Chance————————————————
    Verdictdarkdarkdark0.2mm of rain falling0.2mm of rain falling0.2mm of rain falling0.9mm of rain falling0.9mm of rain falling0.9mm of rain falling0.8mm of rain falling0.8mm of rain falling0.8mm of rain falling0.2mm of rain falling0.2mm of rain fallingdarkdark
    Rainchance————————————————
    Rainmm0.40.40.40.20.20.20.90.90.90.80.80.80.20.20.20.9
    Grasssoakedsoakedsoakedsoakedsoakedsoakedsoakedsoakedsoakedsoakedsoakedsoakedsoakedsoakedsoakedsoaked
    Groundbogbogbogbogbogbogbogbogbogbogbogbogbogbogbogbog
    Temp10°10°10°11°11°11°11°10°9°9°10°10°10°10°10°10°
    Windkm/h55545249454238353232333333333332
    Daylight———✓✓✓✓✓✓✓✓✓✓✓——

    Growth: barely growing (growth potential 0.12). Enough to be worth cutting. Growth decides whether a cut is wanted, not how well it will go, so it is not one of the rows above and does not move the chances.

    Friday 23 OctoberReasonably confident

    No — 0.2mm of rain falling.

    Limiting factor:grass wetness

  6. Saturday 24 October: no hours worth using. No — ground waterlogged.
    Saturday 24 October, hour by hour
    5am6am7am8am9am10am11ammidday1pm2pm3pm4pm5pm6pm7pm8pm
    Chance————————————————
    Verdictdarkdarkdarkground waterloggedground waterloggedground waterlogged0.8mm of rain falling0.8mm of rain falling0.8mm of rain falling2.1mm of rain falling2.1mm of rain falling2.1mm of rain falling1.1mm of rain falling1.1mm of rain fallingdarkdark
    Rainchance————————————————
    Rainmm——————0.80.80.82.12.12.11.11.11.10.2
    Grasssoakedsoakedsoakedsoakedsoakedsoakedsoakedsoakedsoakedsoakedsoakedsoakedsoakedsoakedsoakedsoaked
    Groundbogbogbogbogbogbogbogbogbogbogbogbogbogbogbogbog
    Temp10°10°10°10°11°11°11°11°11°12°12°13°14°15°16°16°
    Windkm/h18161413131417212531374140363332
    Daylight———✓✓✓✓✓✓✓✓✓✓✓——

    Growth: growing slowly (growth potential 0.25). Enough to be worth cutting. Growth decides whether a cut is wanted, not how well it will go, so it is not one of the rows above and does not move the chances.

    Saturday 24 OctoberReasonably confident

    No — ground waterlogged.

    Limiting factor:grass wetness

  7. Sunday 25 October: no hours worth using. No — 0.3mm of rain falling.
    Sunday 25 October, hour by hour
    5am6am7am8am9am10am11ammidday1pm2pm3pm4pm5pm6pm7pm8pm
    Chance————————————————
    Verdictdarkdarkdark0.3mm of rain falling0.3mm of rain falling0.3mm of rain falling0.3mm of rain falling0.3mm of rain fallingground waterloggedground waterloggedground waterloggedForget itForget itdarkdarkdark
    Rainchance————————————————
    Rainmm0.40.40.30.30.30.30.30.3————————
    Grasssoakedsoakedsoakedsoakedsoakedsoakedsoakedsoakedsoakedwetwetdampdampdampdampdry
    Groundbogbogbogbogbogbogbogbogbogbogbogsoddensoddensoddensoddensodden
    Temp17°17°17°16°16°15°14°14°14°14°14°14°13°13°13°13°
    Windkm/h37394042434444444443424139373633
    Daylight———✓✓✓✓✓✓✓✓✓✓———

    Growth: growing steadily (growth potential 0.38). Enough to be worth cutting. Growth decides whether a cut is wanted, not how well it will go, so it is not one of the rows above and does not move the chances.

    Sunday 25 OctoberReasonably confident

    No — 0.3mm of rain falling.

    Limiting factor:ground firmness

  8. Monday 26 October: no hours worth using. No — 0.1mm of rain falling.
    Monday 26 October, hour by hour
    5am6am7am8am9am10am11ammidday1pm2pm3pm4pm5pm6pm7pm8pm
    Chance————————————————
    Verdictdarkdarkdark0.1mm of rain falling0.1mm of rain falling0.1mm of rain falling0.1mm of rain falling0.1mm of rain fallingForget itForget itForget itForget itForget itdarkdarkdark
    Rainchance————————————————
    Rainmm0.20.20.10.10.10.10.10.1——————0.10.1
    Grasssoakedsoakedsoakedsoakedsoakedsoakedsoakedsoakedsoakedsoakedsoakedsoakedsoakedsoakedsoakedsoaked
    Groundbogbogbogsoddensoddensoddensoddensoddensoggysoggysoggysoggysoggysoggysoggysoggy
    Temp14°14°14°15°15°15°15°15°15°15°14°14°14°14°14°15°
    Windkm/h2119161312141718151061017212426
    Daylight———✓✓✓✓✓✓✓✓✓✓———

    Growth: growing steadily (growth potential 0.35). Enough to be worth cutting. Growth decides whether a cut is wanted, not how well it will go, so it is not one of the rows above and does not move the chances.

    Monday 26 OctoberReasonably confident

    No — 0.1mm of rain falling.

    Limiting factor:grass wetness

  9. Tuesday 27 October: 5 hours worth using. 1pm–6pm — ground soft — 66mm rain over the last week, medium (loam) soil
    Tuesday 27 October, hour by hour
    5am6am7am8am9am10am11ammidday1pm2pm3pm4pm5pm6pm7pm8pm
    Chance————————————————
    Verdictdarkdarkdark0.2mm of rain falling0.2mm of rain falling0.2mm of rain falling0.2mm of rain falling0.2mm of rain fallingGood to goGood to goGood to goPrime timePrime timedarkdarkdark
    Rainchance————————————————
    Rainmm0.30.30.20.20.20.20.20.2——————0.10.1
    Grasssoakedsoakedsoakedsoakedsoakedsoakeddampdampdampdrydrydrydrydrydrydry
    Groundbogbogbogbogbogbogbogbogsoggysoggysoggysoggysoggysoggysoggysoggy
    Temp15°15°15°15°15°15°14°14°14°14°14°14°14°14°14°13°
    Windkm/h39383737363534343332312928282727
    Daylight———✓✓✓✓✓✓✓✓✓✓———

    Growth: growing steadily (growth potential 0.36). Enough to be worth cutting. Growth decides whether a cut is wanted, not how well it will go, so it is not one of the rows above and does not move the chances.

    Tuesday 27 October · 1pm–6pmLow confidence this far out

    1pm–6pm — ground soft — 66mm rain over the last week, medium (loam) soil

    Limiting factor:ground firmness

  10. Wednesday 28 October: no hours worth using. No — 0.3mm of rain falling.
    Wednesday 28 October, hour by hour
    5am6am7am8am9am10am11ammidday1pm2pm3pm4pm5pm6pm7pm8pm
    Chance————————————————
    Verdictdarkdarkdark0.3mm of rain falling0.3mm of rain falling0.3mm of rain falling0.3mm of rain falling0.3mm of rain falling0.5mm of rain falling0.5mm of rain falling0.5mm of rain falling0.5mm of rain falling0.5mm of rain fallingdarkdarkdark
    Rainchance————————————————
    Rainmm0.30.30.30.30.30.30.30.30.50.50.50.50.50.50.10.1
    Grasssoakedsoakedsoakedsoakedsoakedsoakedsoakedwetwetwetsoakedsoakedsoakedsoakedsoakedsoaked
    Groundbogbogbogbogbogbogbogbogbogbogbogbogbogbogbogbog
    Temp12°12°13°13°14°14°15°15°15°15°15°15°14°14°14°14°
    Windkm/h27282930313233343536373838383736
    Daylight———✓✓✓✓✓✓✓✓✓✓———

    Growth: growing slowly (growth potential 0.32). Enough to be worth cutting. Growth decides whether a cut is wanted, not how well it will go, so it is not one of the rows above and does not move the chances.

    Wednesday 28 OctoberLow confidence this far out

    No — 0.3mm of rain falling.

    Limiting factor:grass wetness

good to go touch and go dark, frost or snow already goneFainter means fewer forecast runs agree.

How you feel about mowing

Sensible middle ground.

Petrol or battery. The baseline.

Growth

How fast it is growing, and when it will need cutting again.

12%Barely growing

Of the fastest this grass could grow. The turf-industry measure, from today's temperature and day length.

The lawn is barely growing, so it does not need cutting. Leave it — taking leaf off a sward that cannot replace it costs more than it gives.

Held back by both temperature and short days — 10.5 hours of daylight at 10°C.

Over the next 10 days
about 9mm of leaf
Next cut due
not within the next ten days

This only knows temperature and day length. Feeding, watering, shade and cutting height all move it, so treat it as a rough guide.

Worked out from the PACE Turf growth potential model and day length —how and why.

Seeding

Soil temperature at germination depth, and when the window opens.

Soil temperature in TR18, Cornwall

11.9°C53°F

at 6cm — germination depth

Seeding conditions are open — soil is 11.9°C at 6cm and holding above 9°C.

Warming over the next 10 days.

Cross-checks against an independent estimate from air temperature (11.1°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 use 9°C as the seeding threshold.

Thresholds for every species

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 neededDays to sprout
Perennial ryegrasslikely yours8°C5–10
Red / chewings fescuelikely yours8–10°C10–14
Tall fescue10–12°C10–14
Browntop bentColonial bentgrass10–12°C14–21
Smooth-stalked meadow grassKentucky bluegrass12–13°C14–28

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 not growing fast enough to make much use of 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.

Why timing beats product choice

TR18, Cornwall in detail

Soil temperature in TR18, Cornwall is currently 11.9°C at 6cm, and rising about 2.3°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 11.9°C at 6cm and holding above 9°C.

3 of the next 10 days look workable. The other 7 are held back by wet grass or soft ground. As for the weekend: nothing doing. ground waterlogged.

The next recommended window in TR18 opens at 1pm on Tuesday 20 October, because that is when the dew has burnt off — earlier than that and you are cutting wet grass. Underfoot, the ground reads as firm after 7mm rain over the last week, medium (loam) soil.

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Single-model forecast here — no ensemble covers this location, so there are no odds to show. Forecast from Open-Meteo, refreshed through the day. Soil temperature is modelled, not measured — how that works and where the thresholds come from.