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Raised bed - rubble and topsoil mix?

Good morning image

I hoped someone could help me ou with a truly novice question on my new flower beds.  I've got the handy-man to make me a 2 sleeper high raised bed all the way along my neighbours fence.  This is the first thing we've done in the garden so are complete novices, but looking forward to buying our first plant ever!

I've got my pond liner to go along the fence side, and now i'm wondering what the heck i put in there before the plants image?  The beds are 20m long so if i put only topsoil in there i'll be bankrupt, and i guess that wont be good for drainage?  The handy man reckoned i needed Type 1 rubble, and then topsoil but couldn't tell me how much of each.

If i fill them half (1-sleeper deep) in Type 1, and then half (1-sleeper deep) with topsoil will this do the job? 

Thanks in advance for your help




  • nutcutletnutcutlet PeterboroughPosts: 26,790

    I don't think a pond liner will protect a wooden fence. Wood needs to breath, Having a pond liner against it won't stop it getting wet when it rains but will stop it drying afterwards.


  • natalie 4natalie 4 Posts: 21

    hmmm i hope it would dry since it's still exposed on my neighbours side? so long as they dont do the same beds on their side it shoudl be okay, right?

  • nutcutletnutcutlet PeterboroughPosts: 26,790

    I fear it will rot starting from your side. But see what other people think.

    Re the other part of your question, I don't know what type 1 rubble isbut I don't think you need all topsoil over that depth. I can't do sums very well but length x width x height gives you the cubic measurement and a lot of those big bags hold a cubic metre.


  • natalie 4natalie 4 Posts: 21
    Thanks nutcutlet. I can Work out the measurements I need okay, just not sure what the % I need is. I was thinking 50% rubble, 50% topsoil but no idea if that's right?
  • nutcutletnutcutlet PeterboroughPosts: 26,790

    Nor me natalie, sorry

  • floraliesfloralies Haute-Garonne SW FrancePosts: 2,114

    Am I right in thinking the raised bed is against your neighbours fence? Perhaps It would be better if you had sleepers along the back in front of the fence as well so as you have a completely enclosed raised bed that does not impact on the fence. It will need good drainage but like nutcutlet I don't know what type 1 rubble is. do you have access to your local councils green waste compost, as this might help to fill it up.

  • WelshonionWelshonion Posts: 3,114

    If you rot the neighbour's fence you will end up replacing that at your expense.

  • KT53KT53 South WestPosts: 7,299

    Are the sleepers laid flat or on the narrow edge?  If they are flat then you won't have enough depth to put rubble in and then top soil.  If they are on edge you can put rubble to a little under half the depth and then top soil to finish.  Do bear in mind that the soil will drop quite a bit as it settles and rain pushes it down into the rubble.

    I have a raised bed 3 sleepers high and the soil has dropped about 4 inches in 12 months.

  • hogweedhogweed Central ScotlandPosts: 4,050

    Sleepers are about 10 ins by 5 ins. Depending on how you have laid them, then you have either 10 ins or 20 ins to fill. If your beds are 1m wide, then a metre bag of topsoil will cover 4 m to a depth of 10 ins. 5 bags for a length of 20m. (Not sure how the bags are measured, whether by weight or volume but 1 tonne of topsoil will cover 2.5 sq m at 10 inches I think).  Double that for 20ins deep.

    What are the raised beds sitting on? If it is soil, then you need to dig it over before adding the topsoil to make sure it is not compacted. I would not add any rubble to the beds as 10 ins is not that deep.

     What do you intend planting into the beds? (I do think sleepers along the back wall would resolve any issues with your neighbours fence before they start!).


    'Optimism is the faith that leads to achievement' - Helen Keller
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