I am often asked when is the best time to scarify a lawn? For the cool-season-type grasses that we have here in the UK the answer is quite simple … only when the lawn needs it and only when the grass is growing strongly enough to recover!
The grass in your lawn has two main growth periods, spring and autumn. This is why experts agree the best time to scarify is the spring or autumn. If anyone tries to tell you otherwise, then they either don’t know the facts or they are just trying to fill their work schedule during slow months!
So, in summary, here is my month-by-month guide to scarifying your lawn:-
JANUARY OR FEBRUARY – SCARIFYING IN THE WINTER MONTHS IS NOT RECOMMENDED!
Your lawn is in hibernation. The cold weather, frozen soil and generally frosted grass will not take kindly to any mechanical work at this time of year. Scarifying in the cold winter months will damage your lawn and it is best left alone.
MARCH – SCARIFYING IS POSSIBLE IN MARCH … WEATHER DEPENDANT!
As the ground warms, your grass will begin to show signs of growth. Depending on how the weather turns, scarifying in March can be attempted. I would take some soil temperature measurements to make sure that the grass roots are warm enough to be growing well. Look for a temperature of at least 8 degrees Celsius and a showery weather forecast and you should be okay.
APRIL – APRIL IS USUALLY AN IDEAL SPRING SCARIFYING MONTH
The soil is warm, the grass is usually in full growth and there is often plenty of moisture around in the form of April showers. However, some spring months have been rather sporadic in recent years, with some being cold and dry. If this occurs in your area, then I would postpone any scarification work until the autumn. April is usually the best time to scarify your lawn.
MAY – IN SOME YEARS, MAY CAN BE A SAFE MONTH TO SCARIFY
As the temperature in the UK increases, the cool-season grasses slow down their rate of growth. Especially if may turns out to be hot. If this is the case, put the scarifier back n the shed. If it is cool and wet, you can scarify, and you lawn will recover quickly. Scarify it too hard though and you risk a ruined lawn for the whole summer!
JUNE, JULY OR AUGUST – AVOID SCARIFYING YOUR LAWN IN THE SUMMER!
Summer is the time when you want to use your lawn, not pull it apart through scarifying. If your lawn is terrible, or you have inherited a new lawn at this time of year, then the best you can do is keep it fed, watered, and weed-free and put off any major work until the autumn. If you must do something, then a summer aeration can work wonders, but refrain if the ground is baked hard with drought!
SEPTEMBER OR OCTOBER – AUTUMN IS THE BEST TIME TO SCARIFY YOUR LAWN.
In September and October the soil is still warm, the air temperature cools and the moisture levels generally rise. All these factors encourage grass into it’s second growth spurt of the year, which means that this is the ideal time to scarify your lawn. This is the time when you can go at it as hard as you can. The Lawn Man promotes overseeding your lawn during this period, so if you chose to do that you can take the lawn back down to soil and re-seed with a more suitable grass. The lawn will sit over the winter and will be absolutely gorgeous the following year!
NOVEMBER – YOU CAN SOMETIMES SCARIFY IN EARLY NOVEMBER, BUT BE CAREFUL!
Temperatures can fall quickly at this time of year. Keep and eye on the weather forecast and soil temperature and decide at the time. If frost is forecast, or if the soil is less than 7 degrees Celsius, then I would put the scarifier in the shed. Also, if the soil is too wet, definitely postpone. If in doubt, stay off it and postpone it until next year or you could do more harm than good!
DECEMBER – DO NOT SCARIFY YOUR LAWN IN DECEMBER
It is too cold and the lawn will be in hibernation and will have no chance of recovery. Stay off it and postpone any mechanical work until warmer times!
For further information about the best time to scarify your lawn, get in touch or ask a question and I will be happy to advise.
I have a problem with heavy thatch which means my grass has almost stopped growing. Is it better to go in deep one-time in Autumn and get to where I can see the soil or should I scarify several times over a longer time? Also, am I right in assuming that there is little point in over-seeding until I catch sight of soil rather than thatch?
Always scarify more. It is important to get down to soil or your risk just drowning the new growth underneath. Overseed and the lawn will come back strongly.
Be aware though you can get a HUGE amount out!
Good luck.
Thanks Kris.
Ive now scarifier it about 8 times with an electric scarifier set to -10mm. Its removed all the grass but still not reached the soil. Im not sure what to do next. Do I carry on, or maybe rotivate it or give up? Either way it will now need completely re-seeding.
Hi Tony,
Electric scarifiers are not really powerful enough to scarify a lawn properly. They’re more Lawn rakes. You could probably be there all day and not get down to the soil.
A good quality solid bladed petrol machine would be a preferred choice. These can be rented or ask a local lawn company.
Thanks for reading.
Kris
I am hiring a scarifier in September (first time), is there anything I need to do after scarifying? I have loads of clover and other weeds like black medic, oxalis, common yarrow etc and want to get rid of as much as I possibly can!
Hi Ruth,
I recommend controlling all of the weeds several weeks before scarifying. Applying a full spectrum lawn weedkiller should control nearly all of those. This will give you a clean slate for scarifying six weeks later. If you don’t those weeds will just come back even more vigorously with the new space that is created from scarifying work.
A lawn regeneration in Hale, Cheshire
I recommend contacting a local lawn care service to apply a professional weed control product safely.
Thanks for reading.
Kris, The Lawn Man
Hello,
We had a couple of young and I feel inexperienced “gardeners” who scarified our lawn on May 28th with a hired large scarifier.
To be honest, it’s been scalped with huge bald areas and some areas of grass seem to gone black.
Are you able to recommend treatment or given that we have a 5 month old puppy, shall we just live with it until the autumn? We’re really very cross and have asked for a refund of the £150 that we were charged.
I can send photos if necessary.
Thank you so much.
Kind regards
Louise
Hi Louise,
That is a shame, but quite common, I am sad to say.
If you have a dog though, it is going to be difficult to get the lawn to recover due to constant traffic, digging and urine. Dogs and a nice lawn don’t really mix well.
However, the method of fixing does really depend on the level of damage. If the lawn has not been scarified enough, and there is still thatch in the lawn, like my example here, then the lawn will need to be scarified further to get down to soil and re-seeded.
However, if the treatment is down to soil, then patch repairing should help the lawn to recover much more quickly.
If you are in doubt, then I recommend contacting your local independent lawn treatment expert and they will be able to advise the best course of action for your lawn.
Thanks for reading.
Kris
I am going to scarify my lawn in April. How soon after scarifying should I feed the lawn?
Hi John,
I would feed the lawn straight after scarifying. The grass will need all the correct nutrients to enable it to recover quickly and the feed will get down to the roots quickly with all the thatch gone.
Thanks for reading!
Kris
Hi Kris I have done the final cut on the lawn and it is now covered in leaves.
Should I leave the leaves on the lawn?
If not could I use the scarifier to get them up? Thanks Kath
Hi Kath,
No don’t let the leaves stay on the lawn. They will shade out the grass and it will die underneath. A scarifier is not the best tool for leaf collecting as, even on a high setting you will most likely damage some grass leaves. Best to either use a rake, a blower or just use your mower on a high setting
Thanks for reading.
Kris
Kris…due to the wet weather here in Sheffield I have not been able to do my usual October scarification yet. The last few days have been dry and the forecast for the weekend is similarly good, however the ground is still quite soft. Am I still OK to do it over this coming weekend (I have 2 large lawns)or would you advise leaving it until the Spring now? We have not had any frosts as yet over here.
Thanks
Ian
Hi Ian,
That really depends on the lawn and how badly it needs scarifying. If you do it every year and keep on top of your lawn care routine, then it might not be an urgent treatment and you would most likely be okay in postponing it until conditions are better.
Get down on your hands and knees and have a look down in the sward of the lawn. Scrape into it with your finger. If you can get to soil easily, then it probably doesn’t need scarifying. Have a look at How to scarify my lawn for more info.
Thanks for reading.
Kris
Can you scarifyer if your lawn is wet?
You can, but it can make it really hard work. It’s certainly not advised if the soil is very wet though. I would postpone until conditions improve, if you can.
Lots of useful info in your answers to comments. I will be hoping to scarify in the next few weeks but one lawn has a lot of clover in it. Should I attempt to kill this off first and if so with what. I plan to oversow once done.
Regards John
Hi John, You can try to eradicate the clover, but it’s not a very tough weed and is easy to treat in the growing season next year. Unless it is all over your lawn, you probably be okay leaving it, as the act of scarifying will check it back. Thanks for reading. Kris
Hi Chris I have a lawn that’s thick with moss and weeds it’s mid May . What would be the best course of action . I know If I scarify now I risk the weeds spreading .also timing the weed treatment with grass seed and moss killer all gets a bit confusing many thanks Sam
Hi Sam,
Your best course of action would be to get the weeds under control now, so undertake a weed control program over the summer and get all of the perennial weeds eradicated. Then look at treating the moss, scarifying and laying new grass seed later on in the year. Late august is generally a great time of year to do that.
Thanks for reading.
Kris
Hi
I have lawns which used to be in good condition but over last two years have become full of moss and weeds .
I intend to put moss killer down now and scarify in a couple of weeks.
Then overseed and take weeds out by hand.
If that is correct procedure when do I apply fertiliser
Hi Eric,
I would put an appropriate fertiliser down after seeding, but make sure it doesn’t not contain any weedkillers as this may damage the grass. Thanks for reading!
Kris
Hi, we had our lawn laid last summer and we have scarified the lawn with weed and feed on it. I have now seen after reading your article that really we shouldn’t have done this for a few years…obviously there’s nothing we can do but do you have any advice? Thanks 🙂
Hi, I’m wondering if it’s too late to scarify this year? I’m planning on getting a company in to do the work but am a bit worried they will just tell me it’s fine even if it’s actually not optimal. The temperatures are cooling down and I think there was a very light frost this morning. I’m worried that doing anything over the next couple of weeks could be damaging….? Many thanks
Hi Rachel,
The depends on where you are really. Here in Manchester I will still be scarifying for a couple of weeks yet, as soil temperatures are still good and there are still no sign of frosts on the horizon.
I would say October generally is okay in most areas of the UK, but would certainly not recommend scarifying after that unless it is still particularly warm.
Thanks for reading!
Kris
Hi I had a new lawn laid in April. I want to keep it looking nice but there is lots of straw like grass mixed with the green healthy grass. When can I scarify the lawn?.
Thank you
Hi Rose,
You won’t need to scarify a new lawn for at least a couple of years as there will be no thatch build up.
Scarification will not get rid of the “straw like grass”, that was probably in the turf when it was laid, or is a result of a poor mowing regime, causing the stems to thicken.
Thanks for reading
Kris
Really useful article, thanks.
I’ve just moved into a house that has a large lawn with really thick moss – so thick that it is difficult to mow in places. I plan to hire a petrol scarifier, but I’m not sure if I should do it now or wait till April. Much of the lawn is shaded by deciduous trees, and I read on one website that if the lawn is shaded it is best to scarify in Spring when there is more light for the grass to grow, otherwise it can make matters worse. Do you think this is sound advice?
Hi Paul,
I would scarify such a lawn in the autumn. It is very much best to get the moss out now and get the seed down. You may need to re-apply a moss control in late winter to prevent any re-emergence, but the grass will have a much better start sown in autumn, even in shady areas.
Thanks for reading!
Kris
Hi Kris,
Food and spot weeding aside for a moment, I have a good (new but cheap) fixed blade scarifier and am looking to put to work this Autumn. I really want to improve some lawns that have over an inch of thatch and dead moss and are very spongy underfoot.
My concern is the forecasted warm/dry weather until November will mean lawns (that are not currently watered other than the rain) will become scorched when scarified OR the temperature will become too cold for overseeding later in the year.
I am very impressed with the information you’ve freely provided on this website, however I am in East Lancashire so I expect this is beyond your area of operation. What is the safest way to proceed this Autumn, in your opinion?
It is very unlikely that the sun will be hot enough in the autumn to scorch, and even more unlikely that we will see no rain through to November.
I would aim to get the seed down at the end of September, which should give the grass plenty of warmth, and a good chance of rain.
Thanks for reading!
Kris
Hello Kris,
I have just moved into a house and the three lawns are full of moss and weed, I bought an electric scarifier which I know is not a top of the range one but I am sure it is better than using a rake.
I have treated the lawns with weedol the week before already scarified one of the lawns and aerate it and it looks scalped which you say is ok, but reading your site it looks like in my ignorance I have gone about it the wrong way so I have put off doing the others until I know better. Could you advise me on how to both deal with the lawn I have just done and having put weedol on all of them what to do next. By the way your Web site looks more user friendly than the others I have looked at.
Hi Tom,
Well, if you are not overseeding the lawns then it doesn’t really matter too much if you have applied weedkiller, just continue as you are.
However, if you do intend to seed, then I would wait at least six weeks after applying.
Be careful with the electric scarifier though as they can do more harm than good. They tend to be not powerful enough to actually remove the thatch properly and if overused will just rip the grass to pieces without achieving a lot.
Thanks for reading!
Kris
I have inherited a lawn that has had a few years of neglect, it is compacted, has moss and lichen growth, and one section is heavily weeded.
I have an electric scarifier and would like to get on with some work to get it in to shape for next year but just wanted to check when in the order of work I should do the de-compacting work (with a garden fork).
From what I’ve read I shall be taking the following steps –
1) Weed / Moss killer (wait for as long as instructions say)
2) Mow lawn
3) De-compact soil
4) Scarify
5) Mow
6) Add top coat of mixed sand and brush in with a loom / garden bruch
7) Over-seed
8) Lawn feed
Hi Will, I wouldn’t try to aerate it with a fork because, if it is badly compacted, this will just move the stresses around within the soil. I recommend using a hollow-tine aeration machine to do a proper job of it.
Also, Aerating, after scarifying is generally the best order, but each job is different.
Thanks for reading.
Kris
Hi,
Great information! I just want to check quickly, I plan to scarify my lawn next week as it has never been done! It contains both weeds & moss. Am i right in thinking I should first mow the lawn, then apply moss & weed killer & lawn feed (4 in 1 complete mix) then scarify and then finally spread grass seed where required?
Thanks in advance from a concerned novice!
Hi Lee,
I don’t recommend the use of combined weed, feed and moss products as they are doing jobs which should all be done separately.
Use a moss control on its own first. Then mow, scarify and mow again. Then finally seed and feed.
If you are seeding at all you DO NOT want to put down any weedkiller at this stage as it will inhibit the seed germination.
As you can see, a combination product is just not suitable for this scenario.
Hope this helps, and thanks for reading!
Kris
Hi Kris,
I recently bought a machine that has changeable scarification and aerating blades/spindles. I have used both on different halves of the lawn and to be honest can’t see a lot of difference between each half. Both seem to remove a similar amount of moss/grass. Would you expect to be able to see a significant difference in the appearance of the lawn depending on the treatment?
Great site. Cheers – Robin
Hi Robin,
If the machine is of professional grade then yes, you would see a considerable difference, although I’ve never heard of any machine which has changeable scarification and aerating blades, as they are very separate jobs!
Thanks for reading.
Kris
I have just covered my lawn with weed, feed and moss killer, I have noticed that the moss has turned black, presume it is dead. My question is do I cut the grass and then sacrify or vice versa.
Cut the grass, then scarify, (then cut again!). It will make the job much easier giving the grass a really close mow first.
Thanks for reading!
Kris
Hi I just attend RHS course and last week we just been took how lawn companies try be busy in quiet months. I am very surprise and impress about your advice.
Hi Lukasz,
Thanks for your comments, it is true many companies ignore doing the right thing in favour of filling their work schedule, good to see that some folk notice that The Lawn Man is different!
Regards
Kris
After reading your advise I have cancelled green thumb who arranged to come tomorrow,don’t know why they advised me it was fine to do it even on a frosty day.
Hi Chris,
Glad to provide you with information to help you make a wise choice for your lawn care. Scarification in the winter is a really unwise practice, and unfortunately still very common industry-wide.
All the best.
Kris
Hi Kris,
After reading your informative guide on scarifying, I tried to show this to our gardener BUT as you mentioned the work is slow for them in winter, so sacrificed!! IF there is frost there, surely scarifying is not possible, or is it? We live very near the sea and the ground was frosted over. Am I right that we should have waited until spring for scarifying? Any idea what temperature should be there to carry out scarifying? Your help would be very helpful to show our gardener.
Best wishes,
Kiran
Hi Kiran,
Thanks for reading.
You should only scarify your lawn when the grass is growing strongly. This is only in periods of warm soil temperatures, good sunshine and rain. Usually this is spring and autumn.
At this time of year (November) the frosts have arrived and the grass has slowed its growth. This means that if you scarify it aggressively and take all the leaves off then the grass will just stay damaged all winter. It will look awful and be prone to disease, rotting and moss ingress on the soil surface, as there will be no leaves to protect it. This is bad news and you may not have a very good lawn next year.
So yes, you should have waited until spring.
Regards
Kris Lord
Hi, I purchased a Bosh electric scarifying m/c last spring, I scarified my lawn last spring & when finished it looked quite rough, later great. Now though I am seeing signs of moss! I live in the north east would it be safe to scarify now as it’s quite mild for time of year or should I wait until spring?
PS
Did I purchase a good m/c? The Bosh m/c doesn’t use wires but small blades.
Hi David,
No I wouldn’t scarify now (late November) as the frosts have started and the lawn will not be able to recover for a long time, causing problems.
Moss ingress is generally a symptom of weak grass, so if you are getting thick moss every year, try to look at why that might be and look to cure the source problem rather than just tackling the moss. Have a look at my article How to scarify a lawn for more information on how to judge if your lawn really needs scarifying or if other treatments maybe more suitable.
I can’t comment on your machine, but do know that electric machines are generally a fraction of the power of a professional scarifying machine, which would clean the lawn much more thoroughly.
Thanks for reading!
Kris
Hi, Just wanted to say a big thank you for such clear, explicit and really helpful advice – makes a massive difference to novice gardeners like myself!
Glennis
Thanks for reading Glennis!
This is very useful information. I have scarified only part of my lawn today, it was quite long and lush and quite damp but now seems to look awful very ruffed up and has left bare patches! Have not done the rest as I am afraid it will not recover. Should I have cut it shorter prior to doing the scarifying or should it look like this? Please help.
Norman.
Hi Norman,
I would give it a month and see how it gets on. Sometimes you can be a little too aggressive and some patches may struggle to recover, for these areas you can repair with a little grass seed and topsoil. If it was a very lush lawn beforehand, it will have a good healthy roots system and should be just fine.
Thanks for reading
Kris
Hi Kris,
All sound advice but I have just one query (at the moment). We are waiting for delivery of a scarifying machine and intend doing the job at the end of September or early October. Would we need to scarify in the spring as well?
A nice informative concise website.
Michael
Hi Michael,
If you scarify your lawn properly in the autumn then it won’t need doing again for a number of years, however if you don’t do a very thorough job, or just use a lawn rake or a cheap machine with wire spring tines, then you probably will need to go over it again.
Basically, doing a thorough job with a proper scarifying machine in the autumn will save you lots of work in the future!
Thanks for reading.
Kris
I’ve scoured the web for information about lawn care but this one has to be the most organised well informed one yet. Thank you!
I live in the greater London area. Temperature today is 8C and no frost is forecast for the next several days. Plus there are rain showers forecast. Can I go ahead and use my new scarifying machine?
Hi Roshan, Thanks for your nice comments!
We are just on the edge of the scarification season at the moment, so I think you should be okay to give it a light scarification.
However, if it has a thick thatch layer or if you plan on overseeding afterwards though then I would wait a couple of weeks yet. You should be able to get away with a light “tidy-up” scarification without problems though.
Kris
Very useful advice thanks I have just scarifyed my lawn it was fine yesterday but woke to a frost this morning will my lawn be ok many thanks
Hi Ben,
Thanks for your question.
It won’t die, but it won’t do it any good either.
You should only scarify when the grass is growing strongly, otherwise you will shock it too much and set it’s recovery back quite a few weeks. This dormant period will allow fungal diseases and moss to encroach, which is not ideal at all.
Next time, wait until the soil is warmer!
Kris