Independent comparisons. We may earn from shop links. More info

How to scarify a lawn

Updated: October 2026

You already have a cordless scarifier, the lawn looks tired, and you want the afternoon to go well rather than a brown mess you cannot explain. How to scarify a lawn in the UK starts with the season and a shallow pass on dry grass, not with the deepest notch on the dial. This page does not rank the six machines on the [cordless scarifier comparison](/hub/lawn-and-garden-equipment/cordless-scarifier). If you are still choosing a body, use the [cordless scarifier buying guide](/hub/lawn-and-garden-equipment/cordless-scarifier/sub/cordless-scarifier-buying-guide). Peter F. used the RHS, Stihl UK, Ryobi UK and Electrical Safety First, and did not scarify a lawn for this article. A qualifying purchase can earn a commission at no extra cost to you.

You already have a cordless scarifier, the lawn looks tired, and you want the afternoon to go well rather than a brown mess you cannot explain.

Our top picks

Einhell Einhell GE-SC 35 Li bare

Best overall

Einhell Einhell GE-SC 35 Li bare
8.0/10about £207.99
View offer
WORX WORX WG855E.9 40V bare

Alternative

WORX WORX WG855E.9 40V bare
8.0/10about £229.99
View offer
Einhell Einhell GC-SC 18/28 Li bare

Best value

Einhell Einhell GC-SC 18/28 Li bare
7.8/10about £104.95
View offer
On this page
  1. 1.When, and when not
  2. 2.Mow, then set the depth
  3. 3.The pass, the bag, and the battery
  4. 4.Afterwards, and when to stop

When, and when not

Scarify in autumn, while the grass can still grow back. If you cannot see the soil between the plants, the thatch is in the way. A rake is enough for a small patch. If the target is moss, the RHS puts the work in October or early November. You may also leave the moss. Do not scarify frosted or waterlogged ground, and do not scarify turf that is not yet established. Water sitting after rain is a drainage job. None of these machines pulls a hollow core. A deeper notch will not drain the hollow.

Mow, then set the depth

Mow before you scarify. Stihl UK says mow to about 2–3 cm, then set the blades to about 2–3 mm. About 4 mm is their ceiling, and only for a neglected lawn. Ryobi UK says mow to about 4 cm, on a dry lawn, and not to scarify wet grass. Do not merge those cuts. If they disagree, use the higher cut first and judge the tracks. Set the drum high, then test a short strip. Raise it if the tracks look ploughed. A second pass, if the lawn still hides the soil, goes at 90 degrees to the first, and only after the first pass did not scalp the turf.
Einhell Einhell GE-SC 35 Li bare

Testsieger

Einhell Einhell GE-SC 35 Li bare
8.0/10about £207.99
View offer

The pass, the bag, and the battery

Walk a straight line, overlap slightly, and do not scrub one spot until the soil shows in a trench. If there is a collection box, expect to empty it. UK reviews describe a box that fills in minutes or drops thatch back onto the grass. If your machine was sold without a catcher, rake as you go. Take the battery off before a jam, a roller change, or a stone in the blades. The Supply of Machinery (Safety) Regulations 2008 expect a control that stops when you let go. These listings print no decibel figure. Electrical Safety First tells you to wear ear defenders. Use a sound UK plug and an RCD on the charger.

Afterwards, and when to stop

The lawn will look rough. The RHS describes that look, then a recovery while the grass is still growing. Bald patches after a deep pass need time, seed and a higher setting next time, not another pass the same afternoon. Stop and get help when water sits after rain, when you need cores, when the lawn is too large for the packs you own, or when the turf looks diseased. Shade is not fixed by a scarifier.

Common questions

When in the UK year should you scarify?
Autumn, while the grass can grow back. If you are removing moss and you want it gone, the RHS points to October or early November. You can also leave the moss. Do not scarify in frost or on waterlogged ground, and do not scarify a lawn that is not yet established. The visual test is whether you can see the soil between the plants.
Do you mow first, and how short?
Yes. Stihl UK says about 2–3 cm. Ryobi UK says about 4 cm, and only on a dry lawn. Those are two sources, not one average. Use the figure that belongs to the guide you are following, and keep the first scarifying pass shallow so a shorter mow does not become a scalp. Wet grass is the condition Ryobi UK tells you to avoid. Mow, let the surface dry, then test a strip.
How deep is the first pass?
About 2–3 mm on Stihl UK’s normal setting, and about 4 mm only if the lawn has been neglected. Test a short run. If the tracks are deep, raise the drum, which is also Ryobi UK’s instruction. Do not start on the lowest notch because the listing offers several positions. The amazon.co.uk tables in this set often omit the millimetres, so the lever on the machine is the control you can actually see.
Can you scarify wet grass?
Ryobi UK says no. The RHS also rules out waterlogged ground, and frost. A damp mossy patch in shade is a decision about whether you want the moss, not a reason to scarify into standing water. If water sits after rain, the lawn needs drainage or cores, and a scarifier drum does not pull a core. Wait until you can walk the lawn without the machine smearing the surface.
The lawn looks bald. Have you killed it?
A rough, thin look is what the RHS describes after scarifying, and the grass can recover while it is still growing. A ploughed look after a deep pass is different: stop, keep the next setting higher, and give bare patches seed and time. Do not scarify again the same afternoon to tidy the scalp. If the turf was not established, or the ground was frosted or baked, the recovery is slower, and waiting was the better plan.
When do you take the battery out?
Before a jam, before a roller change, and before you reach into the drum for a stone. The bail should stop the drum when you let go. If it does not, stop using the machine. Wear hearing protection. These listings do not print a decibel figure, so there is no quiet rating to rely on. The charger, when you have one, is the part that plugs into a UK socket.

Related pages

Cordless scarifier battery life

Cordless scarifier

Cordless scarifier battery included, or a bare body

Best cordless scarifier: the score rule and the skip

Cordless scarifier buying guide: batteries, then drum

Sources

Sources listed in the research digest. Last checked on 22 October 2026.

  1. RHS autumn lawn care (retrieved 22.10.2026)
  2. RHS moss (retrieved 22.10.2026)
  3. Stihl UK lawn scarification (retrieved 22.10.2026)
  4. Scarifier definition, outdoor noise regulations (retrieved 22.10.2026)
  5. GOV.UK outdoor noise (retrieved 22.10.2026)
  6. Supply of Machinery (Safety) Regulations 2008 (retrieved 22.10.2026)
  7. Electrical Safety First scarifiers (retrieved 22.10.2026)
  8. Ryobi UK RY18SFX35A (retrieved 22.10.2026)
  9. BBC Gardeners' World lawn scarifiers (retrieved 22.10.2026)