I recently received an excellent lawn care question from reader Nick Diggins. His posted his question on my article called why you should never roll your lawn. He would like to firm up his new enough to make it a lawn good to do Tai Chi on:
Could you advice me on how I can make my lawn good to do Tai Chi on? The best surface for that is a very firm and smooth surface.
I have a very small lawn (about 3m by 4m) and I created it to do Tai Chi on. The garden is on a slope so I built a small retaining wall, levelled and rotavated the (chalky) soil, put topsoil down and then laid turf. Annoyingly it is now bumpy in places even though the turf was pretty much perfectly flat when laid. It’s also a bit softer than I’d ideally like.
Is it really a bad idea for me to use a roller – as I thought this might compact the surface to make it firmer. The Downs in Sussex where I live have a chalk soil and many open ‘heavy traffic’ areas are naturally flat and compact with short grass – perfect for doing Tai Chi on!
Many thanks, Nick
Thanks for the question Nick!
Why has a new lawn become lumpy?
Nick explains in his question that the lawn has been raised. It is supported with a new retaining wall and the soil has been rotavated before laying the new turf.
Soil which has been rotavated contains a lot of air gaps. Over time these air gaps reduce and the soil settles. This can take several weeks or even months. Fresh soil will always “sink” and naturally become uneven.
New soil also does not contain any plant roots. Roots reinforce soil, giving it strength and stability. Like rebars in concrete. A soil which does not contain any plant roots will shift and rain will wash channels through it.
Grass can take months to put down deep, soil stabilising roots. Turf takes almost as long as grass seed to do this because the roots are entangled and have become damaged from when it was lifted. Some turf will not root at all if it has dried out in transit.
As a result, new turf on fresh, rotavated soil will undergo considerable settling and will often become very lumpy. Certainly not a lawn good to do Tai Chi on.
How do you smooth a turf lawn
To smooth a lumpy turf lawn you have two options.
The most drastic solution is to lift the old turf, re-level the soil and re lay the lawn. Personally, if going down this route I would sow grass seed rather than turf. You would then be able to choose the species of grass and the roots will quickly establish. Seeded grass often establishes much better in the long run.
If that is not an option then your second option is to scarify the lawn, overseed it with a similar grass seed and apply a heavy top dressing. The scarification will pull out any grass plants which have not rooted properly and make the way for new grass plants. Overseeding the lawn will be needed as a very lumpy lawn may have hollows which may be too deep for existing grass to grow through. Then top dress to bury the seed.
Apply a sandy top dressing
For the top dressing I would recommend using a topsoil with a high sand content. If you can’t get hold of specific lawn top dressings then a good quality topsoil mixed 50/50 with sports sand would be a good compromise. Don’t use builders sand or play sand though as they may contains salts and bind together too much.
To calculate top dressing quantities I usually aim for at least 8kg or top dressing per square meter of lawn. You may need more if the lawn is particularly bumpy.
To apply the top dressing, simply barrow into piles across the lawn and work it level using the back of a rake. I often use a professional lawn lute, but these are expensive and difficult to use on very bumpy lawns. A rake should be fine for your purpose. You could drag around a long piece of timber or a ladder to help get a flat surface, but some good raking in several directions should be enough.
Then give it a light watering and sit back and be patient.
A lawn good to do Tai Chi on?
To achieve a lawn good to do Tai Chi on, you will need a firm surface. Rolling the lawn will only compact the soils, ruining the structure of the soil so I don’t recommend this at all. You will find that the lawn will thin and the grass won’t grow.
Instead of rolling you need to incorporate more sand into the soil. This will give the soil a firmer texture, while still keeping it open. Top dressing as described above will help this, but going forward also think of aerating the lawn and brushing more sand into the surface.
As the roots of the grass bind the soil together, the lawn will firm up naturally.
With a more sandy soil though I certainly recommend feeding the lawn regularly as sand does not hold nutrients very well. Get in touch with your local lawn care service and I am sure they will be able to advise and give you a regular treatment regime.
I hope this is helpful and again, thanks for reading!
The Lawn Man