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Can I scalp my lawn without damaging it?

Hi all. I am trying to get my lawns in pristine condition but am very new to this. I think my lawn is kikuyu but possibly with patches of buffalo. I’m okay with the renovation causing the loss of buffalo as a result if that is the case, but just want to make sure my lawn is suitable for dethatching before I do it and risk killing the entire thing off.

Its very thick in areas and when I mow it large brown spots appear which I assume is due to a combination of uneven ground and thick thatch build up.
Am I safe to scalp my lawn and dethatch it without causing serious harm to it? Thank you kindly for the help!

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Comments

Jason

Hi @JesseMitchell,

Great to have you join the Bunnings Workshop community. Welcome.

Let me tag @homeinmelbourne who shared a comprehensive lawn renovation project where they scalped their Kikuyu lawn, as well as lawn care expert @Adam_W. Our resident Bunnings D.I.Y. expert @EricL will also be happy to assist as soon as possible.

It might also help them to provide more specific advice if you shared a little more information such as where you are based and how you have recently been maintaining the lawn such as your watering and feeding regime.

Many thanks,

Jason

JesseMitchell

https://www.workshop.bunnings.com.au/discussion/comment/32866#Comment_32866

Hi Jason, thank you for the warm welcome. I can certainly provide some more information. I will also take a look at the post you have mentioned!

I am based in Warrnambool on the south west coast of Victoria, we get quite a bit of rainfall so I don’t have a strict watering regime as such, but if there is a warmer day or few days on the horizon I certainly put the sprinklers on it the day before and again once the heat has eased off.

I mow on a weekly basis this time of year and have recently started to lower the height of the mower each cut to try to thin it out a little.

I also use weed and feed on it each time I notice some weeds starting to appear, typically once every 4-5 months or so, and have used some spray on seasol fertiliser a few times over the last 1-2 years.

Jewelleryrescue

Hi @JesseMitchell

As Gardeners there are many things we can do to help plants.

But I some times ask if the lawn thatches up isnt it following its natural growth pattern. Because if you dethatch it it will do it again.

I used to mow the lawn of an award winning council private garden year in year out for and elderly gentlman and he was very strict about the do s and dont s of his lawn. He was the expert not me.

We never thatched his lawn. And I am not saying you shouldnt if it is very thick and spongy. The award wining lawn and garden never allowed to over grow not saying yours was.

For your lawn there is mininal damage scalping it but maybe not full summer as you really need to keep the water up to it afterwards. Once your lawn thinner and green again consider a 50/50 sandy loom with organic soil smells earthy and rich (not topdressing as thats just dirt no real nutrients possibly) This gives your lawn deeper more drought resistance roots too as well letting water soak in faster and a flatter even ground as sand self levels in time. The down side is it raises your lawn edge up. the award winning lawn was raised up 100mm above path level . I had to use scissors to edge it even though I wanted to use whipper snipper but that was a no no as aone wrong move with a whipper snipper equals damage. to the edge.

But there are more keen gardeners here with more knowlegde that i am sure can offer alternate opinions to guide you too.

robchin

https://www.workshop.bunnings.com.au/discussion/comment/32867#Comment_32867

HI @Jewelleryrescue - I love your approach to learning from others. I learnt to garden from my grandfather. I will offer a counter opinion here though. Thatch is a build up of dead organic matter, more prominent in these running grasses than the ryes and fescues. The problem with the thatch is that it will reduce water and therefore oxygen penetration into the soil where the plants roots are. IT will also reduce the potential for fertiliser to be taken up by the plants roots. So de-thatching is a good thing.

Scalping looks unsightly but won't kill your grass. But I need to be sure what you mean by scalping. Scalping is normally seen as the brown patches left after you cut your grass a bit too short, it's a plants response to having too much removed from the leaf blade. It will grow back. You can de-thatch your lawn without scalping it, they are different things.

JesseMitchell

https://www.workshop.bunnings.com.au/discussion/comment/78783#Comment_78783

Hi Rob, appreciate your insight, thank you.
When I say scalping I mean gradually mowing it down almost to dirt level (say 10-20mm from soil to top of grass) so that I can then effectively use a dethatcher/scarifier to remove what thatch is left. At the moment it is incredibly thick and spongey, and cutting it to a height of roughly 40mm at the moment is causing a lot those brown patches you have mentioned. Though I haven’t tried, I suspect that at this height a dethatcher/scarifier would jam and become stuck in the thick layers underneath.
Ideally I would like to be able to get clear sight through to the soil underneath so I can fill the low spots easily and eventually have a final product that’s filled out and even but not so thick and spongey to walk on. Also as you mentioned it would be great to be able to ensure more nutrients, air and water reach the soil as well, as some areas seem to be promoting the growth of moss it’s so dense.

Cheers!

Jewelleryrescue

https://www.workshop.bunnings.com.au/discussion/comment/78783#Comment_78783

Hi @robchin

Your right I learn from others like you and if you take the time to stop and listen to old builders, gardeners people in general and trades you will start to learn things and if they think you want to learn with out talking to much they will start showing you even more.

I call scalping cutting the lawn with a lawn mower down to near roots to remove a thick spongy layer buffalo gets. The new growth will be just as nice but shorter easier to mow mower wheels not sinking in the grass. It isnt pretty to look at. So you can understand why I would scalp selected lawns I used to do a part time lawn mower business at age 13 and 36 and so many people let there lawns turn into rain forests grass waist height at times trying to save money on less frequent cuts, So only recourse was cut the lawn back savagly in stages to a new managable level. I used to charge double for over grown grass as it simply was double the work and grass removal on top was huge.

People didnt want to spend more money on proper lawn care, only the once. Some times there where new lawn rolls on clay base and the grass was dying in large patches regardless of water added they didnt want to spend money on saving it so I started using lawn clippings to try mulch balding spots this worked slowly. But grass clippings as mulch isnt ideal.

I hear you re thatching as dead material blocking air etc. So you will hire a machine to de thatch would be easier? Another machine to help your root airation is a hole corer takes out in aprox 80mm core holes allowing water and organic top dressing in as well as sand. in a 50/50 mix.

EricL

Hi @JesseMitchell

Some very good in-depth information and advice being shared here by our members. Looking at your photos it does appear that the thatch is quite thick. To avoid unnecessary damage, you should only scarify when the lawn is dry. If the soil is too wet, the scarifier may also tear out healthy lawn plants. Mow the lawn to a height of two centimetres just before scarifying - this is usually the lowest setting of the lawnmower.

It's a given that the scarifier will get tangled and you should be prepared for this as some sections of your lawn will have very thick thatch. Have a sharp knife handy to cut the thatch out of your scarifier.

Your scarified lawn will look very bare, but just like a David Attenborough documentary your lawn will come back to life if the proper recovery steps are applied. I highly recommend having a look at this discussion - Lawn renovation by @homeinmelbourne. It is very well documented, and the steps taken to recovery are easy to follow.

If you need further assistance, please let us know.

Eric

shezere

https://www.workshop.bunnings.com.au/discussion/comment/32893#Comment_32893

Hi EricL I have been reading this thread.. even though its a couple of years old.. and wanted to ask a question... Someone I know had a new mower guy do her lawns. The first strip was a lot lower than normal, and he said to water it well and it will grow back. He also told her, the lawn is thick and will need dethatching in the cooler spring months.. but I suggested steel raking to dethatch the bit that has been mowed low, and to put a thin layer of good quality topsoil over to cover the exposed roots.. another person said that the topsoil would burn the roots and is not a good idea. Was hoping you might be able to clarify for me.. the weather is in the 30C plus atm. Sandy soil.. couch grass. Thankyou.

JacobZ

https://www.workshop.bunnings.com.au/discussion/comment/92724#Comment_92724

Hi @shezere,

There would be no issues applying topsoil over your lawn that has been scalped and dethatched. Some mixes contain a small amount of fertiliser, which in higher concentrations can cause some issues, but with established roots, you won't run into this issue.

The only time you would have to be wary about applying anything, more so concentrated fertilisers than topsoil mixes, is if the turf is brand new and the roots are still young and establishing. It is also not so much to do with the heat, but rather the high concentration of nutrients. At that stage, nutrients such as nitrogen, phosphorus and potassium can cause the roots to dry up, causing the juvenile roots to burn.

So, don't stress about applying topsoil to your scalped and dethatched lawn, it is what lawn professionals do all the time. Just make sure you give your lawn plenty of water over the next few weeks and it will bounce back beautifully.

Let me know if you have any further questions.

Jacob

robchin

https://www.workshop.bunnings.com.au/discussion/comment/112508#Comment_112508

Hi @shezere.

So much to learn isn't there.

I agree with Jacob here - apply the topsoil. Trick here is to not put too much on at one time. Don't completely cover the turf till you can't see it any more. it needs to see the sunlight or it will suffer. In a perfect world you will do this during the growing season and give the area to be treated a feed a couple of weeks before to ensure plant is growing OK. Good luck.

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