How to scarify a lawn – and when – expert tips for a professional finish

Discover how and when to scarify a lawn for healthy-looking grass

Scarifying a lawn
(Image credit: Alamy)

Grass looking a little under the weather? Learning how and when to scarify a lawn will aid healthy growth by removing nutrient-sapping moss and weeds.

Scarification can be an important step in maintaining beautiful grass and refreshing a tired-looking patch. More intense than dethatching a lawn, is the process of removing a build-up of thatch, moss and deeper debris. Doing so will help you to aerate a lawn, when you come to fertilize a lawn, you will find it produces better results since the fertilizer will reach the grass's roots, and not just idle on a layer of thatch, for example. 

'Lawn thatch is predominantly made up of dead grass roots and runners, and while having some thatch on your lawn can be a good thing, too much of it creates a barrier,' explains Carlos Real, Lawn Expert and Managing Director of Total Lawn (opens in new tab)

'As this barrier thickens, it restricts the amount of water, air, and nutrients that can pass through, causing your grass to suffocate and eventually die.'

This is how to scarify a lawn.

How to scarify a lawn

A persons feet and rake, pulling up lawn thatch

(Image credit: Alamy)

You can use a professional machine – the Sun Joe AJ805E is Amazon's top rated buy (opens in new tab) – or a good old-fashioned rake to scarify a lawn. ORIENTOOLS Garden Rake is Amazon's Choice (opens in new tab), and has a useful, adjustable handle.

'Whether you use a rake or machinery is entirely up to you,' says Carlos Real of Total Lawn. 'If you are working with a small garden, a rake will do just fine. But if you have a larger lawn, it would be more beneficial to use a professional machine as it can be quite a tiring job.'

1. Mow your lawn before scarifying

'Before you scarify you should mow your lawn to about 1in and collect any clippings,' says Carlos. 'This may take numerous mows, as each time you mow you should not be cutting off more than a third of the grass, otherwise you risk putting your grass under too much pressure.'

2. Scarify a lawn with a rake

'Go up and down your lawn and gently pull up any moss or thatch with your rake – try not to use too much force, as leaving a little thatch behind will help to protect your lawn,' explains Carlos. 'Dispose of any debris.'

'Now that you’ve removed the top layer, switch direction and use a little more pressure, pushing your rake into the soil. The reason you need to switch direction is because you’ll catch any debris that has been pushed back into the soil on your first go.'

3. Scarify a lawn with an electric scarifier

Carlos says: 'Once you have mowed your lawn, you should start with the lawn scarifier on a high setting and go over the surface a few times. 

'As with a rake, you should repeat the process in different directions, but each time you do reduce the settings so it’s less powerful (and removes less).'

When should you scarify a lawn?

How often you need to scarify depends on numerous factors, including the type of soil/grass you have, the weather conditions in your area, and how well you look after your lawn. Most lawns only need to be scarified once or twice a year.

'Mild weather conditions make the perfect time to scarify your lawn, that way your lawn isn’t too hot/dry or cold/damp – so spring and autumn work best,' explains Carlos Real of Total Lawn. 'Your most rigorous scarifying season is fall (usually September), as heavy raking can leave the soil exposed so you want to avoid the summer weeds. 

'Light scarifying, on the other hand, should be done in spring (around April) as things begin to warm up and your lawn will recover much quicker (without suffering from the heat and dryness of summer which often slows grass growth).'

What month should I scarify my lawn?

Heavy scarification should be done in September, and light scarification should be done in April.

When should you mow your lawn after scarifying?

Once your lawn has been scarified, you will need to assist with its recovery by killing remaining moss and adding lawn grass seed and fertilizer to thicken it up. 

Carlos comments: 'Only once your lawn has reached around 2-3in height should you mow your lawn, cutting around 1in off each time you mow, as once you have a healthy lawn you don’t want to ruin it by putting it under too much stress.'

Why scarify a lawn?

There are multiple benefits to scarifying your lawn, most notably:

  • It allows air, water, and nutrients to reach the soil, encouraging growth.
  • It helps to remove moss and weeds (which, if left to fester, will deprive your healthy grass of all the nutrients it needs to survive).
  • It refreshes tired-looking lawns.
  • It reduces the chances of moss developing in the future.
  • It helps to reduce soil compaction.
Contributing Editor

Ruth Doherty is an experienced digital writer and editor specializing in interiors, travel and lifestyle. With 20 years of writing for national sites under her belt, she’s worked for the likes of Livingetc.com, Standard, Ideal Home, Stylist and Marie Claire as well as Homes & Gardens.