One of the keys to laying a beautiful lawn, and for keeping it healthy for the foreseeable future, is to prepare the soil properly beforehand. This is not a difficult process, but is definitely one that many people get wrong, with disastrous consequences that might not be apparent immediately, but will affect the look of your lawn a little further down the road.
Sometimes, people think they are doing the right thing and lay compost down, or go over the soil with a roller, but these are actually not great ideas and we will explain why in this article.
By the time you finish reading this page, you will be aware of the common pitfalls, and also know the best way to compact soil to lay lawn, and it’s easier than you think.
First steps
Before laying down any top soil or anything else, you need to dig over the area where your new lawn will be put down, making sure to remove any stones, weeds and other vegetation. You could use an herbicide here, but if you do, you’ll need to remove about the top 6 inches or so of the original soil after killing the weeds off.
Choosing the right substrate
It is not uncommon for people new to laying turf to decide to put a layer of compost down, or a soil/compost mix, first. This is a bad idea, and will eventually lead you to have an ugly, bumpy looking lawn.
The reason for this is that compost, or any other medium that is high in organic matter, will decompose after a while, and when it does, parts of the soil and lawn will begin to sink. The end result will be far from the perfectly flat patch of grass you had in mind when you first laid the turf.
So what should you use? Ordinary garden topsoil mixed with sand such as sharp sand is just fine, just spend a little time removing the large stones that you often get included in the bags along with the soil. You should also avoid using building sand due to some of the additives that could harm your soil and therefore your lawn.
Mixing topsoil and sand to a 60/40 or 70/30 ratio will give you the right combination of available nutrients for the lawn, while also providing improved drainage due to the sand. Using too much sand could prevent the grass from getting enough moisture, so stick to the ratios above for best results.
A neutral pH in your soil is essential for a perfect lawn, so get yourself a reader and check it. Ideally, you want soil that measures somewhere between 5.5 and 7 on the pH scale. If it’s too far either side, we suggest you treat the soil with the necessary material, such as lime for example.
When and how to lay the topsoil/sand mix
Now that you prepared the area, and you’ve got your topsoil and sharp/sports sand mix ready, it’s time to lay it down and compress it. It is our advice that you don’t just barrow in your entire load of topsoil and then compress it down. Instead, put down a few inches worth first then rake it.
After that, walk over the soil using your heels, walking with your feet close together, heel to heel. This will compact the soil a little, but not too much and also reveal any soft spots that you can then sort out.
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Be careful not to step on the same area too many times or this will overly compact the soil and this is not what you want, and is the same reason you don’t want to use a heavy roller. If the soil is too tightly compressed the roots of your grass will find it very hard to become established.
Once you are happy that this layer is flat and lightly compacted, add another layer and repeat the process. Continue to do this until all your topsoil is down and you’ve raked it all flat and even.
Getting this part right is really important, so don’t rush it. Take your time and check there are no bumps, soft spots, or other unwanted parts to the soil and that it is as level as you can get it, but with a slight sloping gradient to let excess surface water run and drain away.
After this is done, you could lay your turf down immediately, but if I were you, I’d leave the soil down for a few days first to see if any small weeds begin to pop up and then you can remove them. This will also give the soil time to settle.
If you decide to let the soil sit for a few days before laying the lawn, please don’t leave your turf lying around. Ideally your lawn should be put down as soon as it arrives or at least within 24 hours, so work out your time scale beforehand and order it to be delivered accordingly.
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So, there you have it: how to compact soil for laying a lawn. See? We told it wasn’t that difficult, but there are a few things to remember so here they are in bullet points as a reminder:
- Dig up the intended area and remove any weeds, large stones and other unwanted vegetation. Using an herbicide is fine but you should ideally remove the top of that soil afterwards.
- Use a mix of soil and sports/sharp sand at a ratio of 60/40 or 70/30 to give your plants moisture and nutrients but also good drainage for your lawn that’ll come in handy in the wetter times of the year.
- Lay your topsoil down a few inches at a time, rake it out, and then walk over it heel to heel. This will give you the right amount of compression and compactness, without it becoming overly so.
- Either put your turf down immediately or let the soil sit for a few days to see if any weeds pop up, and then remove them by hand.