How to scarify a lawn

By | October 4, 2018
How to scarify a lawn

Autumn is the best time of year to pull out thatch and dead organic matter from the surface of your lawn (a process called scarification). So, in this post, I am going to go through the basics of how to scarify a lawn.

Does my lawn need scarifying?

Many lawn owners don’t fully understand why they should be scarifying their lawn, they’ve just read that it is beneficial. Learning why lawn professionals scarify is very important to know and it is worthwhile learning how to spot if a lawn needs scarification or not.

Before you do anything, get down on your hands and knees and have a look really good look at your grass. Scrape down into the sward (the surface of the lawn) and try to find the surface of the soil. A healthy lawn will have strong, green grass plants and very little dead organic matter on the surface of the soil. If you have to dig down a little way to find the soil, then a light scarification will pull any dead matter out and let the lawn breathe. If the surface of the soil is several centimetres down, and the grass is generally spongy, then you’ve got a tough job ahead!

Thatch on a lawn

Identifying how much thatch is on a lawn is key in planning your scarification treatment. This lawn has a lot of thatch and will require a great deal of work to clear out all of that dead material.

Scarifier or lawn rake?

Lawn rake is not a scarifier

A lawn rake is not a scarifier

One thing that does annoy me is that many garden advice sources use lawn scarification as a very broad term, describing any action where you are raking the lawn. This is incorrect, as there is a big difference between lawn raking and scarification.

Lawn raking is a very light process, involving either a manual hand rake or a cheap electric machine. These are largely ineffectual at actually removing a problem thatch layer, as they are not strong enough to penetrate the soil. If they are used too much, they end up just ripping the grass to pieces, without improving it in any way.

A professional scarification machine uses a powerful motor to drive rotating metal knives into the surface of the lawn. These can remove an enormous amount of material from a lawn, while leaving the grass plants relatively undamaged. Once you’ve seen the results of a professional scarifier, you’ll want to put the lawn rake back in the shed for good!

Metal scarifier blades

A professional scarifier blades

I am often asked about buying a scarifier. They are expensive. Professional scarification machines can be hired from your local equipment hire shop, or save yourself a weekend and get in touch with your local lawn care technician.

Moss?

The process of scarification is not to specifically to pull out moss, although it does that as a result. The main aim is to improve the growing conditions for grass, so that the moss is discouraged. If you have a moss problem, then it is advisable to put down a moss control treatment at least two weeks before you aim to scarify, as this will make it much easier to remove and also prevent you from spreading the moss spores all over the rest of the lawn!

How to scarify a lawn

The Lawn Man scarifying a lawn

The Lawn Man scarifying a lawn

Okay, so you’ve got your scarification machine, you’ve applied your moss control treatment if you need to, you’ve picked a nice dry day and so are ready to scarify your lawn. The first thing to do is to make sure the blades are running at the correct height. Set the machine as high as it will go, start it up and then on a flat spot in the lawn, gradually lower the blades until they are just making contact with the soil. Go over a test area  and make sure that you are pulling out debris, but not destroying the grass! Then cover the whole lawn, up and down in the same direction (e.g. north and south or east and west), not round and round.

Once you’ve completed a full pass of your lawn, rake and bag up the debris. You can put this in your council green bin for collection or take it to your local green waste amenity tip. If your lawn contains a large amount of thatch then there will be LOTS of waste, up to an entire bin bag per square meter.

A scarified lawn

A amount of waste from a scarified lawn can be incredible.

Scarification Directions

Directions to scarify

Next, check your lawn to see how it has fared, and have another dig down to see how much thatch is left. Many well-maintained lawns only need one pass so if you think that the job is done, reward yourself with a cup of tea and a sit-down. However, very few lawns are well-maintained, so another pass may well be required, and another, and another, and another! My personal record is seven passes over the same lawn and I was still pulling out thatch (and grumbling a lot).

Several passes

An important tip to remember when scarifying is to always direct the next pass at a 45 degree angle to the last. This will pull the most material out of the lawn the quickest way. It is also much better to scarify too much rather than not enough, as you can always over-seed and repair, but it is more difficult to scarify again if thatch is still left in the lawn.

Once you are satisfied with your work, it is a good idea to run a rotary mower over it to pick up any fine debris you may have missed through raking and this will also give you a nice clean finish. That is how to scarify a lawn.

Scarified lawn close up

This grass has been scarified well, and is ready for over-seeding.

To over-seed or not?

Straight after scarifying is the perfect time to overseed your lawn with new grass seed, especially if your lawn now looks like a battlefield. The lawn is thin enabling the seed to come into contact with the ground giving better germination. This will help the lawn to recover more quickly and introducing new grass will freshen your lawn, improve disease resistance and even up any inconsistencies in colour. A top dressing would also be beneficial to plant the seed, and help to level the lawn.

Problems with scarifying?

As Ursula Buchan found out, finding out how to scarify a lawn can be an extremely surprising. The machines can be heavy and awkward and the sheer amount of material that you can remove from a thatch-laden lawn can be mind-boggling. Raking it all up is tough, you’ll get tired and probably earn a number of blisters.

Achieving a good scarification result does improve with experience. I’ve scarified hundreds of lawns and can quickly tell those which are going to be difficult, and in my experience the biggest mistake you can make when scarifying a lawn is that you don’t hit it hard enough. It is much better to go over it far more than necessary and then re-seed, then leave a layer of thatch which then suffocates the lawn, preventing its recovery.

If you would like a quotation for scarifying your lawn, or even just some advice about it, and you live in the Exeter area of the UK, then please don’t hesitate to get in touch and I will be happy to advise.

Kris Lord
The Lawn Man

9 thoughts on “How to scarify a lawn

  1. Pat stroud

    I have a very invasive weed in front garden also in border forget name of it spreads all the time .would scarifying help this

    Reply
    1. Kris Lord Post author

      It depends what the weed is. Can’t really advise without further information I’m afraid.
      Kris

      Reply
  2. Tyrone

    I thought I had a very nice green lawn until I recently used an electric raker, which ripped up chunks of grass or thatch.
    I presume it was that all along not grass and now have many bald patches and the whole lawn needs re seeding.
    I have also used the scarifier and and now have a very ugly looking lawn which looks like if it need a lot of work or even a re lay.

    Reply
    1. Kris Lord Post author

      Hi Tyrone,
      That is one of the problems with scarifying … you can easily overdo it! Reseed the lawn with a new seed and wait the winter and see how it recovers next year. It can take many months to recover though, so patience is the key!
      Thanks for reading.
      Kris

      Reply
  3. clive

    Should heavy scarifying only be done in the autumn.
    Also, I have an electric scarifier which to cassettes,
    wire rake and blades. Would the blades be good enough for a medium lawn?
    I think it is about 1500 watts.

    Reply
    1. Kris Lord Post author

      Hi Clive,
      Electric scarifiers aren’t really scarifier, they are more just lawn rakes that often do more harm than good. You really need a petrol powered scarifier to do the job properly. This does depend on what you are trying to achieve though.
      Thanks for reading!
      Kris Lord

      Reply
  4. Rich Kenington

    Hi Kris,
    I’ve just finished reading your page on scarifying which has been a great help,thanks.
    I have a similar garden to the one shown in the photo – 6 months after.scarifying, which looks great.
    My question is what type of grass seed did you use for that lawn? (I presume something good for partial shade)
    Many thanks in advance.
    Rich

    Reply
  5. Sarah

    Thanks you for writing this. It will help us lots as this is our first lawn. We live near you and are wondering if we should scarify our lawn and put some seed down now…only problem is our son is absolutely loving playing on it. Does this matter? will he have to stay off the lawn for the seed to grow?

    thanks
    sarah

    Reply
    1. Kris Lord Post author

      Hi Sarah,
      Well first you should really consider if you need to scarify it. Many lawns that are well used don’t grow too lush, and so rarely have a troublesome thatch layer. If it is well used, it is likely that it maybe more beneficial to give your lawn an aeration treatment to keep the soil healthy.
      It really depend on the lawn though. If you are in my area, feel free to get in touch and I would be happy to pop round and have a chat with you about it.
      Thanks for reading!
      Kris

      Reply

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