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Raised beds .... treated or untreated wood?


I'm looking at making a raised bed. I'm confused though as to what type of wood to use. I've ready that you should not use treated wood due to the chemicals.

Can someone please clarify?

Also, do they need to be lined with plastic?



  • Blue OnionBlue Onion Posts: 2,963

    I used cement blocks, as I didn't want to use treated wood and I also didn't want to be replacing the boards every three years either!  

    What are you building the raised beds on top of?  Grass?  Cement?  Gravel?  I wouldn't use plastic, unless you intend to line the boards with it to help preserve the wood a bit longer.  I built mine directly on top of grass, and just lined the bottom with cardboard and newspapers to kill off the grass.  I know others have put theirs onto gravel or cement, as that was their only options, and they lined the raised bed with weed fabric to keep the soil in but let the water drain out.  

    Utah, USA.
  • FairygirlFairygirl Posts: 53,918

    I line mine with heavy duty plastic.  Most wood is treated. It's fine. People worry if it's  for edible crops, but I think you'll find it's hard to get untreated wood of any kind. 

    It's a place where beautiful isn't enough of a word....

    I live in west central Scotland - not where that photo is...
  • KT53KT53 Posts: 8,454

    Untreated wood will rot away in a very short time.  Use pressure treated timber and, if you're worried about contamination, line it with plastic to avoid contact with the soil.

  • Thanks all, will go on a section of grass that I'm going to use.

    Plastic is not good either apparently.... chemicals fro plastic too!

    I was thinking to paint it with exterior wood paint that is ecofriendly/low toxicity but am so confused.

    I'd not want to use newspapers as the ink from those is full of chemicals for sure.

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