Forum home The potting shed

Top soil v compost

mandyroberts99mandyroberts99 BedfordshirePosts: 217
I am planting a new bed which I am digging at the moment. It is on a slope and I have built a retaining wall so will level it out to reduce the slope. I need more 'soil' and have rotted manure which I can use but will need more. As multi-purpose compost is cheaper than top soil why do you use top soil in preference to compost?
«1

Posts

  • Hostafan1Hostafan1 Posts: 31,692
    I'd go with top soil. MPC doesn't have much "guts" to it and oxidizes over time.
    Devon.
  • Lizzie27Lizzie27 SomersetPosts: 9,271
    I agree with Hostafan but we did fill our large raised beds with a good mix of manure, home made compost, top soil and MPC to keep the cost down, which seemed to work well. If you can get John Innes 3 MPC at a reasonable price, it's the nearest mix to top soil.
  • mandyroberts99mandyroberts99 BedfordshirePosts: 217
    Sorry my calculations were flawed. Top soil is cheaper than compost but I'd still like to know when you use which? I need about 500l
  • Hostafan1Hostafan1 Posts: 31,692
    I'd only use MPC in pots/ containers not " in the ground" 
    Devon.
  • mandyroberts99mandyroberts99 BedfordshirePosts: 217
    Hostafan1 said:
    I'd only use MPC in pots/ containers not " in the ground" 
    But why?
  • Hostafan1Hostafan1 Posts: 31,692
    Hostafan1 said:
    I'd only use MPC in pots/ containers not " in the ground" 
    But why?
    It oxidises, so in time the "ground" will shrink, not a problem in pots, which tend to be more short term. 
    Devon.
  • pansyfacepansyface PEAK DISTRICT DerbyshirePosts: 20,164
    Multipurpose compost is made from any number of things. Bits of paper, plastic, junk. Just open up a bag and have a good riffle through it. You’ll be amazed. In addition, it is often made up of a lot of the “green waste” that people pay to donate to their local councils. This rots down to nothing. Gas.

    Top soil is made of minerals, stones, stuff that doesn’t disappear into thin air.

    Filling a bed with compost will last for a year, maybe two, and then you’ll have to top it up again.

    Be careful where you buy your top soil though. A lot of cowboys offload stuff that contains mares’ tail, japanese knotweed etc.  Make sure that it has come from a reliable source.
    Apophthegm -  a big word for a small thought.
  • mandyroberts99mandyroberts99 BedfordshirePosts: 217
    Hostafan1 said:
    I'd only use MPC in pots/ containers not " in the ground" 
    But why?
    Just saw your original reply above - thanks
  • Lizzie27Lizzie27 SomersetPosts: 9,271
    I don't know where you get your MPC from @pansyface but the stuff I buy doesn't contain any of the things you describe and it's rather a misleading statement to say that 'green waste' rots down to nothing. Green waste from Council tips is nothing more than grass cuttings, leaves, old wood and branches etc, which is heat treated to break it down quicker into 'compost', essentially the same process as what happens to wood litter on a forest floor. It's a good soil improver.
  • pansyfacepansyface PEAK DISTRICT DerbyshirePosts: 20,164
    I buy mine in plastic bags marked Multipurpose Compost and they invariably contain bits of junk.😕

    OK, not “nothing”. Let’s amend that.  Compared to top soil, green waste rots down to “next to nothing”. 🙂
    Apophthegm -  a big word for a small thought.
Sign In or Register to comment.