Lawn Scarifying

Author: Stefan Palm   Date Posted: 6 December 2021 

Scarifying is the process of removing the build-up of thatch and excessive root zone in your lawn and now is a great time to do it.

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. Keep in mind that the only lawns suitable for scarifying in South Australia are Couch and kikuyu lawns.

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 lawnmower. 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. Scarifying is a multi-staged process. It involves removing the thatch, then thinning out the root zone. You scarify a lawn by using a specialist scarifying machine (more about that later) 

Step 1: Remove the thatch

Removing the thatch is a process where you mow off the surface layer off of your lawn with a regular lawnmower. 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 lawnmower. 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 lawnmower! 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 rejuvenate 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. Scarifiers have a series of vertical blade disks that cut down into the root zone of your lawn. They can be hired from most hire shops.

Step 3: Apply a wetting agent and then  fertilise

After scarifying and or scaping, 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!    

What if you have Buffalo?

Buffalo can't be scarified or scalped like couch and kikuyu. This is because it does not have any rhizomes (underground runners). You can actually mow buffalo right out of the ground if you took to it with your mower like you would a couch or kikuyu. If you find that your buffalo lawn has become too thatchy, then you can remove the thatch with a mower but in a very slow manner and by abiding by the golden rule - don't remove all the colour. You can lower the mower one notch from your previous mow height and give your lawn a mow. This will scalp it however it should not remove all the colour from it. Once it has regained all its colour from this (at least 2-3 weeks), you can repeat the process. In this way, removing the thatch from buffalo is slow and can take months. The ideal minimum height for buffalo is 40mm.  I would only ever attempt to do this from the months of October to March.   

If you need assistance with this, as always give us a call on 82980555 or email me at stefan@paulmunnsinstantlawn.com.au


Comments (4)

Yellow kikayu

By: on 12 January 2022
Hey there i have yellow kikayu i mowed it down close to ground and cored it put fertiliser and top dressed watering twice a day has been a week now not growing back any ideas?

Paul Munns Instant Lawn Response
Hi John Thanks for your enquiry The lawn will take longer than a week to recover. It may take a few weeks for it to return to normal. You shouldn't need to water it twice a day. I'd be watering it once or twice a week Thank you

Is scarifying essential after a removing the thatc

By: on 8 November 2021
I have a deep, thick & choked couch lawn in the Riverland. I have mowed it down as close to ground level as possible, dirt showing through in most spots, some places I can't quite get low enough to get rid of patches of grass. My intention was next to hire a scarifyer, but I found out too late that the only hire machine in the Riverland is not available, possibly for some weeks. Is scarifying essential, or will my low-mow do most of the job? (The ground beneath is quite hard.)

Paul Munns Instant Lawn Response
Hi Thanks for your enquiry Cutting it right back should take out most of it It all depends on how much thatch has built up over time See how you go Thanks

Soil temp for dethatching Santa. Anna

By: on 9 September 2021
As per the title, what would you suggest as the min soil temp for scarifying Santa Anna and Windsor Green

Paul Munns Instant Lawn Response
Hi Steve Thanks for your query Best time to scarify is from October onwards (when temp is above 25C) consistently Thank you

Lawn Service

By: on 1 February 2020
Do you provide an advisory service where you will examine a lawn on site and advise the owner of the best line of action?

Paul Munns Instant Lawn Response
Hi Sally, we do offer a consultation service for customers who have lawn issues. There are two types of consultation services we provide. One is about $220 and the other $350. Please refer to our website for further detail about it. Thank you....Andrew

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