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).
When to Scarify Your Lawn?
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 to Scarify a Lawn?
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 (33)
Do I need to reseed at all after scalp?
By: Richard on 26 October 2024I’ve just done a heavy scalp on my kikuyu lawn. Hadn’t been done for probably 5 years, so looks pretty terrible now. Do I need to put any seed down or should I just wait to see how it comes back first?
Paul Munns Instant Lawn Response
Hi Richard, if it looks terrible after scalping, then you've probably done it right! Over the next couple of weeks, you should start to see green shoots popping up again, and the lawn will continue to recover from there. You can't hurt established kikuyu with a mower, so I would wait for the existing turf to recover on its own and not worry about reseeding. Thanks for your enquiry!
Do I need to do more
By: Jon beesee on 13 October 2024Hi Paul, I have a very spongy Kikuya lawn. I’ve only got a battery operated mower so it’s been quite difficult getting the mow height down to level two. Even at this height I am having a hard time seeing the soil because there’s a lot of straw material that isn’t being picked up by the lawnmower. Does this mean I need to hire a scarifier? I am planning to try and mow it down to level one (the lowest setting) today. But should I wait and maintain it as it is until I can scarify it as I can’t hire one today? Also do I need to apply the greenkeeper on the same day? I finish with all this?
Paul Munns Instant Lawn Response
Hi Jon, thanks for your enquiry. If you're having trouble getting your battery mower to a lower level, you may want to consider hiring a scarifier or petrol mower. Picking up the thatch can be an issue with any mower, so raking up the excess material is probably the way to go. Regarding the timing of scarifying and mowing, it won't be an issue if you mow it low, then scalp on a different day. The downside to not doing it all on the same day is that your lawn will be brown for longer, but it won't affect the health of your kikuyu. Greenkeeper can be applied a few days after scarifying. I wouldn't leave it too much longer than that as the fertiliser will encourage quick recovery.
Spongy lawn hard to mow
By: Joy on 7 October 2024Hi Paul Our 5year old kikuyu lawn is extremely spongy & difficult to mow, even with a self propelled mower. Would scaryfying help?
Paul Munns Instant Lawn Response
Hi Joy. Yes - if your lawn is spongy, then scaping and scarifying would certainly help. Spring is a great time to do that sort of work
Can I scarify Buffalo
By: Simon Thomas on 22 September 2024My buffalo lawn needs thatching. Can I use my scarifier on this lawn. Or should I use another process. Thanks Simon
Paul Munns Instant Lawn Response
Hi Simon. Buffalo lawns should not be scarified. They have a shallow root system and can be easily damaged. If your buffalo is thatchy, you can reduce the thatch using a lawn mower by reducing the height you mow at one notch at a time. Once the lawn has recovered completely, you can repeat the process again. This can be only done from the months of October through to February (in South Australia)
Kikuyu top dressing.
By: Tom on 31 August 2024Getting ready to scarify soon. After doing this how soon after can I aerate and top dress
Paul Munns Instant Lawn Response
Hi Thomas, You can aerate at anytime. With Kikuyu top dressing is not really required unless you have low spots that you are wanting to fill. This is best done when the weather is warm and your grass is growing quickly. Thanks for your enquiry!
When to scarify Santa Anna
By: Chris Smith on 23 August 2024Hi, I have a 2 year old Santa Anna lawn, just wondering when the best time to de-thatch is?
Paul Munns Instant Lawn Response
Hi Chris, the best time to scalp a lawn is once the daytime temperature is 20 degrees plus on a regular basis. Once this occurs and you notice the increase in the growth rate of your turf then is a good time to get this done, that way it will recover quicker. Thanks!!
Scalping a Kikuyu lawn
By: Brendan Myers on 21 August 2024Hi, I have 850 sqm of Kikuyu lawn which is now 4 years old. It has been badly spongy and thatched for the past two summers, causing me to mow at a higher level to maintain some green but it now needs a desperate scalping and starting at lower level without sponge. I normally mow with a ride on but will be using a push mower to scalp. I live at Cohuna which is on the Murray River in north west Victoria. Can you tell me when I could scalp my lawn, do I have to wait until mid October or can I do it sooner? Thanking you.
Paul Munns Instant Lawn Response
Hi Brendan, thanks for your enquiry, mid October is fine, you may be able to do it sooner but it really depends on what happens with the temperature. Ideally you want the daytime temperature to be at least 20 degrees on a regular basis. Once this occurs and you notice an increase in the growth rate of your turf that will be a good time to scalp, that way it will grow back quicker. Thanks!!