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 (20)

kikuyu

By: on 13 March 2021
hi I got kikuyu lawn installed 6 month ago ang is very tall and spongy already. Is it possible to cut down to the ground height to re start this autumn? I bought munn's pure kikuyu seed as well , can i saw it after short cut mowing this autumn?

Paul Munns Instant Lawn Response
Hi There Thanks for your query I wouldn't cut it right down now, I would recommend waiting until Spring (October) October is an ideal time to cut your lawn right back

Maintenance after dethatching

By: on 10 February 2021
Hi, Thanks for this article - exactly what I was looking for and the recent comments and answers very helpful! Once I have dethatched, what would the mowing plan be while the lawn is still recovering? Should we continue to mow twice a week or wait for it to bounce back first?

Paul Munns Instant Lawn Response
Hi Lucy Thanks for your query You would start mowing again once the lawn starts to recover, approx. 2 weeks after dethatching. Thanks again for your question

Santa ana

By: on 8 February 2021
I have Santa ana that was laid around 9 months ago now. It’s very green and very healthy but getting a little too spongey under foot for my liking. Is it to young/to late in the summer to scalp it right back?

Paul Munns Instant Lawn Response
Hi Scott Thanks for your query You can scarify it now (February) or you can wait until October. Thank you

Have I left it to late to scarify?

By: on 7 February 2021
Hi, thanks for all the useful info. My Kikuyu has been down for almost a year now and has become very spongy. I’m in Geelong, Victoria. Have I left it to late to scarify to de-thatch the lawn? If so should I just maintain and fix next October?

Paul Munns Instant Lawn Response
Hi Sean Thanks for your query You can still de-thatch your lawn now. I wouldn't leave it too much longer though. Otherwise you can wait until October. The warmer it is, the quicker it will come back

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

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