Scarifier for thatch, aerator for compaction. They fix different faults, and a lawn can have both.
The two tests
The spongy test. Walk on the lawn. If it feels springy and soft, like walking on a mat, there is thatch between the leaf and the soil. That is a scarifier’s job.
The puddle test. After heavy rain, does water sit on the surface for a long time on ground that is not obviously low? Push a screwdriver in — if it takes real force, the soil is compacted. That is an aerator’s job.
A lawn that is both spongy and hard underneath needs both operations, in that order: scarify to remove the thatch, then aerate to open the soil under it.
What each machine is
A scarifier has a shaft of fixed vertical blades that cut down through the thatch and drag it out. It is a powered machine on this shelf, electric or petrol, and it produces a startling quantity of material.
An aerator makes holes. Three versions exist and they are not equivalent. Spikes push a solid tine in and displace the soil around it — quick, cheap, and on heavy soil they can make the compaction worse at the hole wall. Hollow tines remove a core and leave it on the surface, which genuinely relieves compaction and is the only version that does. Slitting cuts narrow vertical slots, somewhere between the two.
The spiked shoes and rolling spikers on this shelf are the first kind. The hollow-tine hand forks and the coring machines are the second.
Why they arrive as one machine
Because a powered scarifier is a shaft in a housing, and swapping that shaft for one carrying spring tines turns it into a raking and lifting machine. Most machines on this shelf are sold with both cartridges and named for both jobs, which is where the confusion starts.
How this site handles it
The scarifier family here is the powered machines, and the aerator family is the hand tools and rollers. The pages say which cartridge a machine ships with and which is an accessory, because a two-in-one machine supplied with only one shaft is a common listing and the second one is a separate purchase.
The questions that keep coming in
My machine says Vertikutierer and Rasenlüfter. Which is it?
Usually both, with two interchangeable cartridges: a blade shaft for scarifying and a spring-tine or spiked one for raking and aerating. The German listing names both functions in one line, and the parts are separate.
Are the spiked shoes any good?
They put holes in the surface, which is the easy part. They do not remove a core, so on genuinely compacted soil they push the compaction sideways rather than relieving it. On a light lawn they are adequate and very cheap.
Last reviewed 26 September 2026