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 (6)

What to do for Buffalo lawn

By: on 24 November 2018
Hi, I have a Sir Walter Scott lawn but is very spongy underfoot, what do I do.. In the past did not mind a bit of movement as it felt safer for the kids when they were playing and taking tuimbles!.

Paul Munns Instant Lawn Response
Hey Sandra, When buffalo gets spongy, it can be hard to remove the thatch. I suggest you lower your lawn mower by a notch or 2 and then mow your lawn. This will remove some colour from it. Once you have done this, you must allow it to fully recover. Keep repeating this process till the thatch thickness is 40mm thick. Remember not to scalp your buffalo too hard otherwise you may damage it.

Santa Ana - post scarifying problem

By: on 6 November 2018
Hi, I laid Santa Ana in Octover 2016 and it all went in nicely (ordered from Paul Munns). I sacrified (with a lawn mower) in Sept 2017 and within 4 weeks the lawn was as good as new, it was green, lush and thick. I scarified again a few weeks ago (Sept 2018) and it hasnt come back looking all that good, it is patchy, has a couple of dead parts and it isnt as lush and green as last year. Is there something I have done wrong? When I scarified this year I took the mower blade down a notch lower than last year as I wanted to remove as much thatch as possible. Have we not had enough warm sunny weather so far? Will my lawn look the way it does all summer? What can I do to get the thick lush lawn I had last year? Thanks

Paul Munns Instant Lawn Response
Hey Matt, Scalping your Santa Ana lawn with a mower is a good thing to do from time to time to control the thatch. To add to that, you can't damage a Santa Ana lawn with a mower, no matter how short you cut it so the problems you are experiencing are not as a result of you scalping the lawn. If you don't see any improvement over the next week, I would recommend you to bring a 20x20cm core sample of the turf and bring it in to our store so that we can trouble shoot it.

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

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