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  Colin Hunt July 5, 2012 at 11:08am

  Break up the sub soil with a fork to aid drainage then add top soil.  Warn the customer that this isnt ideal and they may have the outline of the pond re-appear when the ground is dry.  I would put this in writing at the end of the quote.
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  Ian Olpin July 5, 2012 at 11:10am

  Thank you, Colin.
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  David Cox July 5, 2012 at 8:42pm

  If your down to the subsoil you could have trouble - Subsoil by its nature is "dead" its beyond the depth where soil has enough air circulation to support root growth usually, so few plants if any can root into it.

  It also tends to be where minerals and salts acumulate through percolation of rain water, so can be quite saline and depending on the AREA either very acidic or alkaline - check this first.

  If you have to be simple, add about 200mm of topsoil and fertilize well... I would expect problems with moss and grass growth after 2 years or so due to week deeper rooting.

  A better approach would be to go for 30-45cm topsoil... or 15cm rotovated into 15cm of subsoil to "mimic" a normal soil horizon profile, Then 30cm of toilsoil over that giving you about 60cm of good soil profile.
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  Busy Bee Garden Services Limited July 6, 2012 at 6:01am

  We did something like this not so long ago where we had to remove a shed base and return to grass, after we took the concrete away it left a great hole, we broke up the sub soil and filled it in with topsoil then turfed, been done 6 months and the best grass in the garden!
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  Ian Olpin July 6, 2012 at 11:56am

  David Cox said:

  If your down to the subsoil you could have trouble

  Thanks for that. I have to be simple, because I am!

  On reflection,  because of the relative lack of depth due to the finished turf having to abut the customer's recently laid patio, I'm constrained by the lack of depth to work with. Do you think rotovating might be the wiser choice? Just have to give the pond concrete footings a good wide berth, I guess.

  The pic will hopefully make things clearer. The spoil is going to be carted before I start, apparently.

  Thanks...
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  David Cox July 6, 2012 at 12:04pm

  hmmm

  Its going to be a big of a pig to get a LONG term good result - Id say mix in 50/50 topsoil compost into the top layer of the sub soil and then topsoil turd as normal - this would mimic a normal Soil hozion (http://en.wikipedia.org/wiki/Soil_horizon) [look at O - A - B Soil horizons to see what I mean.

  This should work fine to be fair. Mix in some chicken manure pellets of if you must, artificial fertilizer, all the way through the soil mix to ensure an Even and fertile base and voila you have created a new soil... with good long term fertility built through its depth.
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  Ian Olpin July 6, 2012 at 1:06pm

  Thanks for that, David.

  See what you mean, lack of depth means working on an element of the subsoil to give the roots a fighting chance. A minimum 100mm depth of quality layer A all over will hopefully prove an adequate soil horizon. :)
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  David Cox July 6, 2012 at 9:06pm

  Youve got it!

  If the subsoil is a clay - may be worth working in sharpe sand instead of Compost - just bear in mind... The deeper the roots can go, the lusher, longer lasting, healthier the lawn will be.,
  
  Ian @redbarrow.com said:

  Thanks for that, David.

  See what you mean, lack of depth means working on an element of the subsoil to give the roots a fighting chance. A minimum 100mm depth of quality layer A all over will hopefully prove an adequate soil horizon. :)
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  Brook Landscaping July 7, 2012 at 9:50pm

  Hi

  Break out all concrete, turn over or rotavate subsoil and bring in at least 150mm of topsoil.  Landscape Architects should specify this and if asked this would be the minimum specification we would carry out.
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  Ian Olpin July 8, 2012 at 1:02pm

  Brook Landscaping said:

  Break out all concrete

  Thanks for the advice, James. Although not obvious from the photo, the pond footings are relatively wide and deep, and the budget won't stretch to removal, unfortunately. Same reason a lot of the prep has been DiY.

  As David's advice above, decided to work in sharp sand to remaining subsoil and then 100-150mm sandy loam topsoil on top. Fingers crossed

  As a 53 yr old 'newbie', who although spent a good few years landscaping in Spain, never had much call for turf, funnily enough, it sometimes feels like sitting in a potting shed picking the brains of The Gardening Council of Elders. Virtually-speaking, of course! :). 

  Thanks all, for freely sharing knowledge and experience; what a fantastic resource this is.