Scarifying your lawn

Date Posted: 20 November 2018 

Scarifying is the process of removing the build-up of thatch and excessive root zone in your lawn. It helps return a thick, spongy lawn back into a green, tight knit surface and is something you'll need to do at least every 2 years.

(The following information applies to Couch and Kikuyu lawns only).

Over time, you may notice your lawn getting  thicker and spongier. You may also notice your lawn discolouring each time you mow it. These are indications that it may be time to remove your lawns thatch layer and thin out the root zone.  Thatch is the spongy surface material that builds up in lawns such as couch and kikuyu. The best way to describe thatch is a straw coloured exposed root type material that exists between the soil level and the blades of your lawn as illustrated in the image below.  

The more thatch you have in your lawn, the harder it is to keep green.  This is because thatchy lawns are easy to scalp with your lawn mower. The lawn blades typically only occupy the top 20mm of your lawn. For example, if your lawn is 100mm tall, you would have 80mm of thatch and 20mm of blades. If your lawn is 150mm tall, you would have 130mm of thatch and 20mm of blades.  If your lawn gets too thatchy, when you mow it you are more likely to mow off the lawn blades exposing the brown thatch underneath.  When this happens, most people raise their mower height by a notch or two so that they don’t scalp it next time. The problem is that within a few months, the lawn will grow more thatch and you’ll be back to scalping it again. The answer is to remove the thatch and then change your mowing habits. If you find that you’re scalping your lawn between mows, it’s better to mow more often than it is to raise your mower height.   Raising your mower height only leads to more thatch.

How do you scarify?

Scarifying can be done from about October through to February for Kikuyu and Couch but the very best time of year to do it is October and November.Scaryfying is a multi staged process. It involves removing the thatch, then thinning out the rootzone. Sometimes, just removing the thatch is enough. Other times, you must thin out the rootzone as well.

Step 1: Remove the thatch

Removing the thatch is a process where you mow off the surface layer off of your lawn. If your lawn is thick and spongy, it is unlikely that you will be able to remove all the thatch with one pass of your lawn mower. The best approach is to just keep mowing it down notch by notch till you have completely mown the lawn down to soil level. The more soil you can see when you’ve finished, the better job you’ve done. Rest assured, you can’t damage a couch or kikuyu lawn with a lawn mower! This process will completely remove the colour from your lawn – this is expected and normal.  Don't be surprised when you remove an enormous amount of thatch. so it's a good idea to prepare where you're going to put all the clippings. Often, just scaping is enough to rejuviate your lawn. It will return your lawn to a low, flat surface making it easier to keep green. If you want to go the whole hog, proceed to step 2!

Step 2: Scarify the rootzone

This is where you use a specialised scarifying machine to thin out the root zone. Over time, the rootzone of couch and kikuyu lawns thickens up which can impede the life and health of the lawn. Sometimes called Verti mowing, this pruning and thinning out process removes dead and woody organic matter which re-invigorates the lawn and allows it to grow new, fresh stolons and rhizomes. Scarifyers have a series of verticle blade disks that cut down into the rootzone of your lawn. They can be hired from most hire shops.

Step 3: Apply a wetting agent and then  fertilise

After scarifying and or scapling, treat your lawn with some liquid wetting agent and a complete fertiliser such as Paul Munns Greenkeeper. Liquid wetting agent will ensure that water and nutrient penetrate evenly and deeply. This will help your lawn recover faster.

As I mentioned earlier, at this point your lawn will look pretty terrible. Don't be alarmed at all by this - the warmer it is, the faster the lawn will grow back. After 2 weeks you’ll be able to see a green layer returning and typically after 4 weeks, your lawn will have completely recovered but with no thatch!    

Comments (16)

What happens if I scrape / remove the thatch in Ju

By: on 31 May 2020
Hi my lawns is thick and in one spot I have been removing the thatch a little each week. Will it damage the lawn if I do it now or just take longer to grow back

Paul Munns Instant Lawn Response
Hi Jonathan Ideal time to do it is in Spring. If you cut it right back now it will take a lot longer to come back

Kikuyu instant lawn extremely spongy

By: on 17 May 2020
Hi, My instant lawn was only laid around 6-7 months ago and it is extremely spongy lovely and green but very spongy! It’s difficult to push the lawn mower through it and I can only use the highest 2 settings. Will scarifying/de thatching be ok after this winter? I’m in Melbourne Just a little curious as it is a relatively new lawn and expensive one at that I don’t want to destroy it! Cheets

Paul Munns Instant Lawn Response
Hi Connor Thanks for your query Best to wait until Spring (around October) to scarify/de thatch your lawn If you are using your mower to de-thatch your lawn, cut it down in multiple steps on the day until you are at the lowest setting. Trying to cut it right back in one hit will cause your mower to keep cutting out Your lawn may look dead for a few weeks but will quickly return to naturally glory. Andrew

Can I scalp mow couch Lawn in January or will it b

By: on 17 January 2020
My 40 year old couch lawn is growing in lumpy tuffs in patches up in the air as it were, yet beside the lumpy tuffs some of it is growing flat next to the soil, I'm guessing it needs scalping??? However can I scalp mow the couch Lawn in January or will it be too hot to grow back in Perth WA. I cut one lumpy tuft back to the ground with scissors, which when I lifted it up in the air with my hand revealed long stalks lying on the ground which was covered with the green tufts growing up in the air L shaped growth habit if you know what I mean. Difficult to explain. Thank you for your webpage, I look forward to your reply.

Paul Munns Instant Lawn Response
Hi Jo You can still cut it right back now. I wouldn't wait too much longer, the sooner the better. The warmer it is the faster it will recover....Andrew

Do I top dress low spots after a heavy dethatch

By: on 20 October 2019
I have mown my kikuyu down to pretty much soil, can I top dress the low spots in the lawn now or wait for recovery to start?

Paul Munns Instant Lawn Response
Hi Daniel Thanks for your question You can top dress now, just do 5mm at a time. Thanks.....Andrew

Thatch in agridark turf

By: on 9 March 2019
Hi I have agridark lawns at my house. They have become full of thatch. Should I scalp it to remove the thatch? Will it recover ok?

Paul Munns Instant Lawn Response
Hi Barry Argidark is a relatively new variety of couch and one that I haven't had any experience with. Being a couch, it can be scalped to remove the thatch and it will recover however I am unsure how long it will take. I suggest that you approach Qualturf for more specific advice.

De thatching

By: on 9 March 2019
I have a Kikuyu lawn which is 2 years old. I top dressed it with peat, which really improved it, however it will need dethatching, is it too late to do it this year?

Paul Munns Instant Lawn Response
Hi Sue, Depending on where you live, it most likely isn't too late to scalp and scarify Kikuyu. Providing your lawn is healthy and thriving, you'll need about 6 weeks of temperatures exceeding 23 degrees C to get a recovery.

Adelaide Hills Thatch Removal

By: on 28 February 2019
Hi, I have Male Sterile Kikuyu lawn located in the Adelaide Hills which has been down for about 8 years. It has never been dethatched or scarified and quite spongy. Is October - February the correct period for the Adelaide Hills? Thanks

Paul Munns Instant Lawn Response
Hi Robert, You need average ambient temperatures to exceed 23 degrees for kikuyu to grow. This would make October to February a good window to de-thatch and scarify kikuyu.

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