Scarifying your lawn

Date Posted: 30 September 2017 

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

Scarifying is the process of removing the build-up of thatch in your lawn.  Thatch is the spongy surface material that builds up in lawns like 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 in the image below.  

Over time, you may notice your lawn getting thicker and thicker. You may also notice your lawn discolouring each time you mow it. These are indications that it may be time to remove this thatch and thin out the root zone.  

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. When you mow it, you’ll mow off the blades exposing the brown thatch.  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.

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 late October.

How do you scarify?

Step 1: Mow off the surface layer from your lawn. You won’t be able to do this all at the same time so 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.  You can go one step further and thin out the rootzone using a motorised scarifyer however for most home lawns, this isn’t necessary.

Step 2: Fertilise the lawn with a complete fertiliser such as Paul Munns Greenkeeper. This will help it recover faster.

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 with no thatch!    


Comments (4)

Scarifying new lawn

By: on 22 October 2018
Thanks for the article, very helpful. In June this year I installed Kenda Kikuyu using instant roll-out turf. It has been growing well but is now very spongy. Is it too soon to scarify given it was only laid ~ 4 months ago?

Paul Munns Instant Lawn Response
Hey Ryan, Given that its only 4 months old, I'd give it till after Christmas before scarifying it. That will give it a chance to get some roots in the ground. Even then, you'd probably only need to scalp it rather than scarifying it. Scalping it (ie mowing it to the ground) will get rid of all that thatch.

vertimowing

By: on 22 October 2018
Hi. I am going to vertimow to remove the thatch and loosen up the top surface, should I still cut it right down to dirt with the mower first, or not quite as low with the mower, or not at all and just normal height. After, I was going to core it, and then put some seeds down to fill the edges that are a bit patchy and light on for grass, feed it with the "golf course green" and some wetting agent. Any other tips? Regards, Jason

Paul Munns Instant Lawn Response
Hey Jason, Looks like you're considering a full renovation of your lawn. This would be all OK for a mature couch or Kikuyu lawn but not for a buffalo. If you do have couch or kikuyu, I'd scalp it down as low as you can first to get rid of the surface thatch before scarifying. The rest sounds really good - especially the wetting agent. That's a step most don't do but it really pays big dividends for the long term health of your lawn.

When should you resume mowing?

By: on 8 September 2018
Thanks for the article, how soon after scarifying should you start mowing? Thanks

Paul Munns Instant Lawn Response
Hey Laurence, It depends on how warm it is as to when you would start mowing again. The warmer it is, the faster the lawn will recover and require mowing. It is usually at least 3 weeks before you'll get back on your lawn with a mower after scarifying

What sort of watering regime do you recommend duri

By: on 27 October 2017
Thanks for this article, just what I was looking for. Can you please advise what sort of watering program we should be using when we are in the process of scarifying? Thanks

Paul Munns Instant Lawn Response

Hi Sarah,

After you have scarified, your watering regime shouldn't really change too much. Watering at this time of the year for a couch or kikuyu should be around once per week for around 30 minutes per zone. This ideally should be the equivalent of about 20mm of rain. With this amount of moisture, your lawn will recover quickly.


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