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Soil prep for new turf

This is my first post so please forgive any breaches of etiquette.

I have recently had some major landscaping done which included taking up and relaying about 120m2 of lawn.  My soil is heavy clay but the old turf was well established and drainage was not an issue.  There was a slope on the original lawn which has been levelled off by adding topsoil to a depth of about 6 inches at the lowest point.  The topsoil used was the "best quality" which is incredibly fine and it has packed down so the water cannot drain and in places the turf is sitting on what I can only describe as silty mud.

The guy that did the landscaping has agreed that it needs replacing so I've lifted the turf ready for him to prep the ground properly.  

My question is, what does he need to do to prepare the soil? Would adding sharp (not builders) sand help, or would horticultural grit be better?  Should he rotovate into the clay?

For info, I've decided to let the ground settle for 3 months after his prep work is done so the new turf can be laid in the spring. 

Any advice will be gratefully received.



  • Dave HumbyDave Humby Posts: 1,145

    Hello John and welcome to the forum.

    Regarding your situation I think you may well have answered the question yourself. You have clay soil, you had a slope and no drainage issues. You no longer have the slope and now you have waterlogging.

    The topsoil should work as a drainage medium, I'd be surprised if it has got so compacted in such a relatively short period of time but if it has then adding some coarser product may help the water permeate down through it.

    Clay is a 'funny' beast. I remember a golf course that I was a member at for quite a few years they would 'chase' poorly drained areas around year after year getting them sorted and the following winter a new area that had historically been relatively dry would become wet!

  • Thank you for the welcome and response Dave.

    The clay bed has not been disturbed and is still sloping so if the water can get through the topsoil it should drain as theory anyway.

    The worry is that drainage would be affected if he rotovates into the clay.  


  • BorderlineBorderline Posts: 4,700

    With regards to the clay soil underneath. Whether it is rotovated or not, in time, the compacted structure will return. When the weather gets warm again, you can work on that soil again when it's still damp but not sodden. Turn the top 12 inches of soil and rake it into smaller pieces. Then throw in fine grit or sand and work that into the soil. You will need to walk over the areas a few times to tamp it all in to level and remove air-pockets. 

    With regards to best quality top soil. I think this will not help your situation and a waste of money. Any topsoil will do. You are laying turf over that. Leave the best quality top soil for the annual top-dressing instead.

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