Lawn Scarifying

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

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 lawn's 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, and 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 root zone

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. A 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. With such a mild start to Spring, warm-season lawns such as couch and kikuyu have been slower than usual. You probably noticed that they emerged from Winter a little later and haven't been as vigorous as they would usually be at this time of year.  Heat combined with sunlight are the catalysts that make your lawn grow and recover faster, neither of which we've had a whole lot of this Spring.  Because of this, expect your lawn to take a little longer than usual to recover from scarification this season. If you want the best chance of it looking green again this side of Christmas, I wouldn't leave it past next weekend.

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