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Raising clay soil by 3-4 inches, what to add?

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  • K67K67 Posts: 2,506
    @nollie I too have clay alkaline soil what acid compost mix did you use please.
    As to grit I though the horticultural grit was the one you need but I just add to the planting hole and mix as it's far too expensive to use on the whole bed in the quantities you really need.
  • WaysideWayside Posts: 845
    The ecological hit of adding tonnes of grit/compost/sands to beds must be huge.  Horse manure from the farm next door not so bad.  Makes me think you'd be better with domed/raised beds, and possibly using green manures: comfrey/alfalfa - to up the organic ratio in the soil.  I've chalk, with little top soil, and it seems however much I add, it ultimately disappears, so I'm starting to rethink all planting.
  • raisingirlraisingirl Posts: 7,093
    bark chips as a surface mulch can add bulk without weight and reduce the degree to which the soil drops - settles - with heavy rainfall.
    Gardening on the edge of Exmoor, in Devon

    “It's still magic even if you know how it's done.” 
  • NollieNollie Posts: 7,529
    @K67 just tried to look it up for you on my suppliers website but it’s offline because they are rebuilding it, but all their products are made from locally available materials, so I suspect it’s mostly composted pine bark (tho I vaguely remember there were a few ingredients) as there are some big pine forests close to their production facility.

    I also use the acid compost as a thick mulch which my (alkaline loving?) weeds don’t like so don’t appear. I really notice the difference if I disturb the mulch when planting, they spring back up! However, this may be a no mulch/mulch thing rather than it being acid compost per se.
    Mountainous Northern Catalunya, Spain. Hot summers, cold winters.
  • K67K67 Posts: 2,506
    Thankyou @nollie. I am in the uk. I was thinking of pine bark and horse manure mixed as a mulch. Am already planning for Autumn when we have only just started summer!
  • FireFire Posts: 19,096
    "The ecological hit of adding tonnes of grit/compost/sands to beds must be huge."

    I agree. It's all extracted from somewhere and leaves its mark.
  • Thanks everyone!  So at the moment I'm feeling the mix is topsoil, generic soil improver (low cost) and manure (although I will look further into mushroom compost).  Then, once the area is planted up, possibly with grit in some planting holes, a mulch of bark on top, which will mean I have to raise the soil surface less, but will have to top-up.  Phew!  

    I'm hoping that because the soil improver comes from the recycling of Council collected garden waste, the manure comes from, well, a renewable source, and the bark mulch comes from a renewable source, that the bulk of the ecological impact is in my garden not out in the wider environment.  I get that topsoil and grit are different and i'll try to respect that in the decisions I make.  

    If it sounds like I've gone mad with this, feel free to say so :)

    Thanks again to everyone for taking the time to give me ideas and advice, you've given me a great base to work from.  I will do a ph test before I buy anything.  
  • NollieNollie Posts: 7,529
    Good luck Jeniffer, no you are not mad, just a gardener (same thing really!)

     @Wayside possibly another thread so apologies Jennifer for the hijack:

    The ecological impact issue is interesting debate, whilst I’m confident my big bags of compost and manure comes from sustainably produced local waste products of the local building/furniture manufacturing and farming businesses respectively, I have no idea what the impact of the localish (Barcelona) grit extraction is. The big question mark for me is over the bags of generic compost I pick up from garden centres.

    But as gardeners, do we also not put so much more back in terms of increasing the biodiversity of our respective patches, reducing erosion and increasing bacteria with soil improvement and planting - even a lawn is better than nothing. Then what about the impact of extracting any natural materials that we use to build our houses? Or just live in general? Everything we do or buy has an impact, all we can do is try and reduce our footprint as much as possible and put back something in return.

    Since I have improved my soil and thus been able to plant a wider variety of stuff, the population of worms, ladybirds, bees, birds, butterflies and countless other insects has exploded. Not all are welcome as they munch away at my plants and eat my rose buds >:) but I guess nature will find a balance at some stage.
    Mountainous Northern Catalunya, Spain. Hot summers, cold winters.
  • raisingirlraisingirl Posts: 7,093
    Nollie said:

    Everything we do or buy has an impact, all we can do is try and reduce our footprint as much as possible and put back something in return.

    This is true - there is always an impact. The key is to be aware of it, to consider if there are better lower impact options that would also work. The Brandt definition of sustainability - meeting the needs of the present without compromising the ability of future generations to meet their own needs - hasn't yet been bettered. Gravel is, in less than geological timescales, a finite resource, so using it is not sustainable. Likewise peat. Composted bark, rotted manure, composted garden and kitchen waste - all these have some environmental impact - methane release, primarily. But compared to using peat based compost, as far as we know now, the impacts are shorter lived. And if you didn't use them on your garden. the methane release would still happen - the waste that is used to make the products would still exist and still decompose, but the benefits of the improved soil structure and biodiversity in your garden would not. 

    Jennifer - I think your approach sounds perfectly sane. I'd only add to try to mainly grow the plants that like your conditions so you don't have to modify the soil by importing lots of non sustainable material
    Gardening on the edge of Exmoor, in Devon

    “It's still magic even if you know how it's done.” 
  • NollieNollie Posts: 7,529
    Great definition, raisingirl and well- considered points  :)
    Mountainous Northern Catalunya, Spain. Hot summers, cold winters.
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