When is the best time to scarify your lawn?

Scarifying is a very beneficial lawn treatment and rather than being considered as a remedial maintenance exercise every one to two years, lawn enthusiasts should to make this a regular job.

What does scarifying do?

During the course of a season - especially if grass has remained active during periods of the season that would normally see growth slow down - thatch and lateral growth builds, up restricting light and air getting through.

As thatch builds it encourages moss and weeds to take over, leading to a downward spiral for the health of a lawn. A scarifier is in effect a vertical mower with knife blades spaced out along a reel - much like a cylinder on a mower - these blades can be set at different heights and used in slightly different ways.

The deeper the blades and the more extreme and vigorous the action is on the roots, the greater the effect on the grass. A deep incision into the soil will cut through the shallow roots of the grass which in turn should lead to a tillering - tillering is when the grass sends out new shoots from the root base and increase the grass mass by extending its own rootzone. If the procedure is practised on a regular basis this root pruning will encourage a thick rootzone and in the process crowd-out weeds and discourage moss.

A light scarify can be set to brush the surface without any interference with the root of the grass. This is effective if you just want to remove a build up of dead grass or take out lateral growth. I would practice this procedure on a regular basis.

Modern professional equipment is fitted with a grooming reel set just behind the front roller. On every pass over a golf or bowling green, tennis court or cricket square any transient bodies are removed thus keeping the surface aerated and free from build up of lateral growth.

What to do

First try and cut your grass three days before the scarifying is to take place. This will clean up the surface of any leaves or debris as well as a build up of growth. Cut the grass again on the day you want to scarify. This will help to remove any moisture and a further growth of grass.

Scarifying will produce bundles of dead grass so you need to make sure that the machine is not having to labour through the normal vertical grass growth as well.

Set the blades to the required height - if the lawn is dense and springy then an initial pass just into the surface will clear the way for a second lower pass without clogging the collection box too quickly.

Repeat the process until you are satisfied that you have removed sufficient grass and thatch.

Not every scarifier comes with a collection box which means that you may have to collect the grass by raking it up.

I always managed the worst by hand and then vacuum up the last with a rotary mowing machine.

Early autumn is the best time for a deep penetrating and thorough clear out of moss and thatch. Spring (it's best to wait until the hardest frosts have passed to that the grass roots can recover sufficiently) for a light to moderate scarification/grooming. Do you need a scarifier? - Click here.