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How to Scarify Your Lawn(s) This Autumn

Sisis_scarifierScarification or Scarifying is an essential part of cultured turf or lawn management. It is carried out with hand tools such as a Spring Bok Hand Rake or, for larger areas, purpose built machinery called a Scarifier. The aim of scarifying is to produce a healthy vertical type growth of desirable grasses, to improve the turf surface and appearance.

Very light scarification (like with a drag brush or rake on a cylinder mower) is used simply to raise the leaves of the grass in the sward before mowing, to leave a smarter looking finish.

It helps to control the knap or grain, which can form on some types of turf. Rather more severe scarification removes dead and dying parts of the turf (thatch), thus letting in air and encouraging new growth. It also brings up stolons of both creeping grasses and weeds, such as White Clover, allowing them to be mown off. Unwanted grasses, such as Yorkshire Fog, have leaves that tend to lie flat below the height of the cut.

Scarification, by bringing the foliage up to the mower, results in the grass being less conspicuous. Severe scarification tears out much of the surface growth of weed grasses such as Yorkshire Fog and Couch Grass and can weaken the plant to the point of near elimination. Many seed heads of Poa annua grow very close to the ground and light scarification, or brushing, helps to bring a large proportion of these within reach of the mower with a view to reducing the spread of this less than desirable grass. Many fine turf areas are likely to suffer from an excessive production of fibrous material at the surface, and scarification is a big factor in prevention and cure. You can Hire Professional Quality Scarifiers Here.

These can be hired for a Day, Weekend or Week. Scarification of general lawn areas is concerned with many of the same problems met in fine turf management, but with different degrees of emphasis. If a lawn had not been scarified for a long period of time, or perhaps never before, the amount of material taken out will be enormous and will surprise the hardiest of gardeners. Do not be afraid – this is an operation that can only do the lawn good. Scarification is best carried out in two or three passes in different directions, corner to corner and lengthways. For the first pass, do not set the blades too deep (approximately 5mm is ideal). On the second pass, the blades can be set at no more than 10mm and the final pass can be set a little deeper, making sure not to penetrate the soil. All material removed from the lawn should not be put on the compost heap, as it may contain fungal spores.

Scarification is best carried out in the early autumn, especially if over seeding is to be carried out as well. Light scarification may take place in the spring, but it must be noted that the grass should be actively growing or severe damage to the sward may occur. SCARIFYING - STEP BY STEP Check lawn for grass cover. Kill any weeds and moss beforehand at least a month beforehand. Mow the lawn really low, almost scalping it to lose the volume of the grass. It will make scarifying so much easier. If the lawn is predominately moss and weeds and weed grasses, after scarification not a lot is going to be left so you will need to over sow. Scarification is best carried out when the lawn is a little moist – not too wet or too dry. Only carry out scarification when the grass is actively growing, so no later than end of October traditionally and not before grass picks up in the spring months.

This advice goes against the grain of the largest Lawn Treatment Company concept, GreenThumb Lawn Treatment Services who fully condone scarifying in the non growing season. On the other hand Richard Abbot, Managing Director of Lawn3 advises us that their concept and Franchisees do not condone scarifying in the so called 'out of season' winter months when there is little or no growth at all to aid recovery. If there is a serious thatch problem, the spring type tines, which are mounted freely on the axle, should be used. If vertical cutting and seedbed preparation is the target, then the more solid type blades should be used. To set the depth of the blades, go to an inconspicuous area of the lawn and start the blades just flicking the tips of the grass. Set the machine a little lower and go over this small area again.

The aim with de-thatching is to go as deep as possible without disturbing the surface of the soil. The aim for vertical cutting is to go deep enough to root prune the grass, so again do not enter the soil. Only when preparing a seedbed should the soil be disturbed but the Scarifier is not a rotovator!! When the desired depth has been determined, normally by adjusting the front roller, go round the perimeter of the lawn a couple of times as this saves throwing debris into borders and allows a turning circle at the end of a pass. Start by going up and down the lawn in straight lines. Never turn with the blades in the ground. As some machines are supplied with a grass collection box, very little hand raking to clear up should be needed. Workings on lawns that have never been scarified before will necessitate in many empties of the box so it may be easier to leave it off and clear the debris after the second pass.

Scarifying_debrisIf the removed debris is still laying on the surface, a quick way to clear it up is to use a back-pack blower, blowing it off to a place where it can be picked up like into the centre of the lawn. The debris will however need to be reasonably dry. Use the large plastic rake to remove the bulk of the debris. You will find it easier to rake in the direction of the last machine pass rather than across it. Once the first pass has been cleared up, make a second pass but NOT at right angles to the first but on a diagonal to the first pass. You could leave the debris from the first pass on the lawn if there is not too much bulk, to save a raking process and have a serious clearing up process afterwards. Always keep an eye on the weather, as the last thing you want to happen is to be clearing debris that has become wet from light rainfall. This is why it advisable to clear as you go just in case the weather turns against you. When clearing up after scarification, whether blowing or sweeping, work in the same direction as the scarification. If clearing up at right angles to scarification, some debris will be missed.

If the plan is to blanket over seed the lawn afterwards (and after aeration) you can be cruel to be kind and really give it a good damn scarification! Don't be scared, go for it. After scarification, always mow the lawn again in different directions to the scarification. When scarifying, keep the machine as straight as possible, as it will leave stripes as with mowing. To follow - Aerate and Fertilise and blanket over seed and top dress with a loam. Currently at the time of posting this article, the weather in august is wet so you might be able to start the renovation process a little earlier to take advantage of the available soil moisture but the lawn will look a bit of a mess for around 6 weeks until the new seed germinates.


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I recently acquired a very wet and spongy lawn. i can see mostly moss in it, fern like, it looks like it has never been cared for only mowed over 20 -30 years or more. I tried a spade in several places and it sank in fully in height! upto shaft.
I have read what needs to be done but am concerned about scarifing as I think the ground is far too wet and spongy and the machine will not perform.
cheers shirley

Reply: It sounds like the lawn has had it's day. Best thing to do is to mow the volume of the moss down with a mower, grass box off, clear the debris, lower mower, do again in different direction until you can no more off then apply soluble of iron for moss control or a total weed killer and wait for it all to die and off then scarify, aerate, fertilise, over seed and top dress. See Lawn Renovation


I knew nothing about scarifying. Your article was/is very easy to read and understand. I can now look forward to the autumn and a successful scarifying exercise, without the fear of damage. Spring next year 2013 will be something to be excited about.
Thank you very much.

Reply - Thank you! Your kind comments makes our time writing articles to help lawn owners, so much worth it.

John Ferguson

I found this article extremely helpful. I scarified my lawn fairly vigourously in the spring. But after a long dry spell, I found that I have a lot of Clover and also still moss. I have fed and watered the lawn regularly and it does look green. I will be doing scarification and aeration in late September but will use a moss killer before hand.

Thanks for the help

Reply - John - thanks for your kind comments. We are here to help and steer lawn owners in the right direction!


Rod - scarify the whole lawn as you will get funny growt patterns next year. If the scarifier is set correctly, you will soon notice the really poor areas as more debris will be lifted from the sward than in lesser poor areas. Make two passes and then clear the debris and mow low before aerating and over seeding and fertilising.

In the spring, you can lightly scarify a previously scarified lawn to lift any winter debris. Our scarifiers have a spring wire reel that is more a groomer than a thatch removal tine and reel. Little and often is the key with scarifying at times of the eyear when the grass can naturally recover so winter is the wrong time!


I found the article very interesting. My main guidance for lawn care initially was D.G. Hessayon's 'The Lawn Expert'. He doesn't recommend scarifying in Spring at all.

Given what I'd read I was intrigued to learn that a major lawn treatment company did all their scarification in Winter.

Anyway, I scarified my own lawn at the beginning of October. (I live in central Scotland). Slightly appalled at how it looks at the moment, but it was very mossy before.

I've put some seed on the very barest of the patches but I've not much hope of seeing any germination at this stage.

One question about using a scarifier: should I push the machine over the ground at a steady pace,or would it work better to slow the machine at the worst spots?

Mike Seaton


Pleased that Lawn3 read the Blog. Comments noted. I have corrected the article to ommit Lawn3 as a Lawn Treatment Company who insist on scarifying in the non growing season. Lawn3 are one of a handful who do not, so thank you for pointing this fact out.

Richard Abbott

Lawn3 does not in anyway condone scarifying in the winter months; weather permitting, we recommend scarifying in March/April or September/October, normally a couple of weeks after a moss treatment in order to reduce the chances of speading live moss spores. I would be grateful if you would correct this in the article or remove the reference to Lawn3. Regards, Richard Abbott, Lawn3 Limited.

Mike Seaton


Thank you for your kind words, tell your family and friends! In response to your questions - scarify, aerate, then feed then over seed in one day or as soon as you can! It gets the job done quicker and it will be growing sooner too!



B Joshi

Hi Mike

I thank you for providing a very useful information for the people who are not a professional gardner !! I found your comments very precise and helpful.

I have a few little questions. I have lots of Moss. I have used the Sulphate to kill the moss 8 days back and today I am scarifying the lawn.

1) When do you think I should aerate the lawn?
2) How many days should I leave to apply the autumn feed after scarifying?
3) How many days should I leave to sow seed after scarifying ?

Many thanks

B Joshi

Mike Seaton


Thanks for your comment. If you start in the next two weeks and complete the mechanical process and over seed too you will have grass up after around 3 weeks but remember to keep the area clear of leaves. The grass will never stop growing and will ontinue eto grow over the winter months. You stand a better chance if you have Oak trees as they are the last to drop their leaves. Our Team are actively renovating lawns in the same way ahead of the reduction of soil temperatures which are always warmer now than in the spring months. Worst case scenario is that you may need to do some over seeding in the spring and the key this autumn is to fertilise the assist rapid establishment of the grass seed.

The Sulphate of Iron will kill the moss quite quickly so you could scarify after only one week after treatment of the moss.

Hope this helps. Do you like the new banner image?


Hi Mike

I am in much the same situation as Jill - poor quality lawn with a tremendous amount (even a majority) of moss cover. If I follow your advice to Jill and apply moss killer now, and then scarify & aerate in two weeks time, will there be much chance of the lawn being green over the winter as the growing season will almost be over (south east UK)? Will the process be less effective if I did it instead in March, before the new season, or is it best to press on now?

If going ahead now, will a light scarification be likely needed in Spring at any rate, as moss may have reformed?

Many thanks,


Mike Seaton


Thank you for your comment. You will need to kill the moss first with a Ferrous Sulphate - Sulphate of Iron active ingredient either as Lawn Sand or a straight Iron. Leave two weeks to work then start the mechanical work. Seed quickly soon after you have finished scarification and aeration and fertilising -like on the same day. The grass will be germinating in around two weeks but will take some 6 to 8 weeks to establish. You will need to keep the leaves blown off the lawn to prevent smothering but if the leaves get the better of you, you can simply overseed lightly in the spring once you start mowing. Hope this helps in the meantime.



Interesting article, but I'm in a dilemma! I have lawn badly affected by moss (bit neglected and affected by overhanging shrubs). I've cut back the shrubs and am keen to set to with the scarifier, which is a Qualcast one which you exchange in the petrol mower. I believe it's very effective and am expecting some very bare patches - so will need to re-seed. My questions are: Must I use a chemical moss killer first, in which case I won't be able to scarify till end of October, or can I just go ahead with scarifying? I also have some large trees which will start to shed their leaves soon. I'm concerned that if I need to re-seed it will be covered by leaves and won't grow, or raking the leaves will inevitably rake up the new grass. Should I just leave the whole thing until Spring?

Mike Seaton


Thank you for your kind words - pleased to help. The problem you are having is symbolic with amateur scarifiers in so much that you cannot get enough adjustment and happy medium of depth. The blades should only just be touching the ground to lift the debtis from the base crown of the plant with minimal soil disturbance - it is not a rotovator. If you had mown the lawn beforehand really low and the machine is stalling still, try half widths of the machine - so a few extra passes may be required. Perhaps the debris is too great so mowing beforehand to remove the bulk of the volume will greatly assist. I would have thought that the petrol scarifier would be som much better than an electric one. Forget the grass box too, easier to blow or rake up the debris or mow over it to collect once dry. The weather is drying out nicely now and a stiff easterly wind over the lawn ahead of scarifying will dry it out a treat. Keep us in the loop!



Grant Sutcliffe

Thanks for this excellent article with in-depth detail on how to scarify (not found elsewhere).

The reason that I hunted to find such an article is that I recently purchased a B&Q Branded scarifier. I was unsure about its quality. Even with the blades set to the minimum depth (least aggressive), it was not able to cope even though the lawn had been closely mowed. I needed to support it so that the rear wheels where just off the gound in order for the engine not grind to a halt. If the machine rested on the rear wheels, I was not to be able to progress scarifying more than a few steps before it would stop. In the process of those few steps, it would rip up 90% grass.

My concern was that the ground was too wet and therefore causing this to happen. I presumed that this was just lack of knowledge on my part. The blades definitely hammered into the soil even when set to the minimum depth. After reading your article, I am thinking that the B&Q Scarifier is possibly of poor quality and that there might be a design fault.

I last scarified with an electic machine two years ago when the ground was dry with a neighbours machine and had no problem (removing about 75% grass - as intended).

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