My Garden

raised beds - best material to use

Last post 02-09-2009 2:50 PM by Arrem. 16 replies.

• 31/08/2009 10:04 AM
  ann Location: sunderland Joined on: 26 Aug 2009 Posts: 2	Reply | Contact Owing to dogey hips and knees I need to make some raised beds. I guess about two foot high and four foot wide by five foot long would enable me to reach while sitting on a stool. I want them to look attractive & of course to be long lasting. Can anyone advise me about the best wood to use. I had thought about decking.

• 31/08/2009 11:33 AM

  In reply to

  Arrem Location: West Midlands. UK Joined on: 12 Jul 2009 Posts: 90

  Reply | Contact I recently used tanalised joists (3.5m and 1.2M X 150mm),  the type which go under the decking.  My feeling is that if you want them as high as you say, then you should use wood thicker than actual decking.  The weight of the soil pushing outwards would be substantially increased due to the extra height.  The tanalised timbers will last a lot longer than untreated wood. In your situation I would consider building a base structure from concrete blocks and place a raised bed on top of that.  You could then sit at a comfortable height to work on your garden.  You could screen the blockwork with mobile planters which could be removed and replaced as needed. There is no such thing as useless - you can always be a bad example.

• 31/08/2009 12:09 PM

  In reply to

  spade monkey Location: earth Joined on: 27 Jul 2009 Posts: 37

  Reply | Contact Hi, Decking certainly sounds like it would be sturdy for lower edges, but for beds that high, I'd agree with Arrem - that calls for some solid structure to support it. Not sure about what would be 'best' wood, we always end up scavenging what we can and trying to work with that. A main consideration in using wood is what/how the wood has been treated because of not wanting anything nasty to leach out. To avoid that issue, I've always used some kind of lining material to seperate the soil from the edges... when lucky, lining has been easy with large lengths of damp course material, when not so lucky, I've ended up cutting open old compost bags and using those. Obviously not as good with the latter because it is not as practical and does not look as nice, but it's what we had. I'd always go for lining anyway because it will help the wooden edges last longer since they won't be decaying (and releasing chemicals) through having damp soil against them. A 2 foot deep bed would also need quite a quantity of soil, Do you have a plan for filling them? Creating a base then having the beds on top could be the way to go. Have you thought about a brick or a combination of materials? I guess a lot depends on whether you are doing it yourself, with help, or paying someone... Re what Arrem said about screening with planters, the only issue I can think with that is that you might not want to have to move things for access, so the layout / design is important. Did you see the link from one of the other threads with the 'keyhole' garden? http://acornranch.blogspot.com/2009/02/keyhole-stuff.html

• 31/08/2009 01:16 PM

  In reply to

  BB Location: Hereford Joined on: 12 May 2009 Posts: 572

  Reply | Contact Scaffold boards might be worth consideration anne. We have used them for our raised beds and we obtained them very cheaply from our local scaffolding firm. I just gave them a call and asked for some old planks and they were happy to get rid of some. They are very sturdy and while ours are just one plank high I can't see any reason why it wouldn't be possible to make them two high. Do consider the amount of topsoil you will need - it is much more than you might think. BB

• 31/08/2009 02:20 PM

  In reply to

  spade monkey Location: earth Joined on: 27 Jul 2009 Posts: 37

  Reply | Contact BB is right - it's easy to underestimate how much you'll need - it is really surprising. If I've worked this correctly: 24 x 48 x 60 (imperial) is about 0.6 x 1.22 x 1.52 = 1.11 cubic metres A cubic metre is about a tonne of soil. Then you think you've filled it, and it goes and settles! I remember how surprised I was when using a compost bay for temporary soil storage - over 3 tonnes in a compost bay 1.5m each side and high. If the point of raising the beds is to save you bending, some kind of base that gives reasonable drainage and then a good depth of soil on top of that maybe? I didn't think about it before, but that big bay has 12 sq inch posts at the four corners and then one inch boards slotted in as it fills... scaffold boards sound even sturdier.

• 31/08/2009 05:57 PM

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  richardpeeej Location: Leicester Joined on: 22 May 2009 Posts: 807

  Reply | Contact I have built 2 raised troughs 2m x 0.7m,and 1 trough of 2m x 0.4m. I made my troughs from some spare decking .The larger troughs are 2 decking planks tall, and the smaller trough is one decking plank tall, but it is built up on legs (also made from decking planks . I lined the troughs with old compost bags to protect the wood. I am growing runner beans,peas, french beans, lettuce, courgettes, and some  flowers in them. Richard

• 31/08/2009 06:06 PM	In reply to
  spade monkey Location: earth Joined on: 27 Jul 2009 Posts: 37	Reply | Contact  @richardpeeej Do you have any photos of your beds on legs? That sounds like a good approach too...

• 31/08/2009 07:36 PM	In reply to
  richardpeeej Location: Leicester Joined on: 22 May 2009 Posts: 807	Reply | Contact This is a picture of the raised trough on legs:- Main large troughs on stands (shorter legs) but front covered with decking boards:-    also enough decking spare to make window box/planter:-     Richard

• 31/08/2009 09:57 PM	In reply to
  spade monkey Location: earth Joined on: 27 Jul 2009 Posts: 37	Reply | Contact  Brilliant stuff! They look fantastic - all my woodwork looks like some kind of Escher nightmare but those beds look great.

• 31/08/2009 10:05 PM	In reply to
  richardpeeej Location: Leicester Joined on: 22 May 2009 Posts: 807	Reply | Contact Thanks spade monkey but no real woodwork only screwed together, with blocks in the corners, and then varnished. I had to make  centre pieces in the window box and small trough because the planks weren't long enough!! Richard

• 31/08/2009 10:16 PM

  In reply to

  spade monkey Location: earth Joined on: 27 Jul 2009 Posts: 37

  Reply | Contact What you have done there does look like it would lend itself to a slightly deeper bed to suit some root crops though... i.e. double or treble boards for the sides? Do you think the way you've done the legs would support the weight of extra soil in the middle of the bed (without bowing)? Makes me want to go down to the reclamation centre and find old decking right away!  You should put the plans/measurements etc online - they look ideal for people without much space or mobility. Nice one.

• 01/09/2009 09:10 PM	In reply to
  ann Location: sunderland Joined on: 26 Aug 2009 Posts: 2	Reply | Contact Thanks to all who offered advice. There is no obvious choice but I think decking would look attractive so I will price it tomorrow. I had not considered how much soil needed - another problem to face. Ann

• 01/09/2009 09:50 PM	In reply to
  richardpeeej Location: Leicester Joined on: 22 May 2009 Posts: 807	Reply | Contact Why not try 'freecycle' Ann they seem to be in all areas- take a look on Google its free to join and you can see what people are wanting to get rid of -you usually just have to collect it - maybe worth considering. A friend of mine had a free lawnmower! Richard

• 01/09/2009 09:55 PM

  In reply to

  spade monkey Location: earth Joined on: 27 Jul 2009 Posts: 37

  Reply | Contact The calc I did was a rough one but based on 2 feet deep which makes the soil requirement much bigger - looking at the method richardpeeej used with beds on legs, that could reduce the requirement. What will make the difference is what you want to grow... salad = shallow, parsnip = deeper If you want to go for a deeper bed with wood, then Arrem's method looks worth more than a passing thought. Everything is just opinion of course...  but do tell us what you decide on.

• 02/09/2009 09:30 AM

  In reply to

  Roundelder Location: NW Cumbria Joined on: 15 Apr 2009 Posts: 174

  Reply | Contact Hey Richard Dude, cool set up there - show off! You haven't considered starting a raised bed export (to Cumbria) biz by any chance? Further to what spademonkey mentioned re treated timber, the only thing I would be a little wary of would be what the varnish contained. Given the slightly "hostile" environment of whatever growing medium is used, I  think you could end up innadvertently impregnating it with leachate from certain if not all wood preservatives or finishes although I would happily stand corrected on this. At the risk of sounding an utter killjoy BB.for the same reason I would also need to know if the scaffold boards had been treated with chemicals and if so what. Mind you, I can also imagine the response from the scaffolding firm were I to request such information! Wide awake Roundelder