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Is treated decking dangerous?

MerrickMayfairMerrickMayfair Posts: 13
in Problem solving
We put down some new decking in the autumn and I've recently discovered the wood has been pre-treated. I'm concerned about toxins getting into the soil as I plan to put in new raised beds this spring and grow food. 

Would it be better to ensure the raised beds are sealed off from the ground and only contain compost? 

Thanks


Posts

  • KT53KT53 Posts: 9,016
    People actually use decking as the 'walls' of raised beds.  You are worrying unnecessarily.
  • ObelixxObelixx Posts: 30,090
    Assuming your treated decking wood is being used to build the raised beds it will help protect the wood if you line the beds with plastic which can be just compost bags cut opened and stapled to the inside or specially bought plastic available by the metre in good DIYs and GCs.

    It will reduce the amount of moisture absorbed by the wood from direct soil contact and delay inevitable rotting over the years and will also stop leaching between the wood and the soil in both directions.
    Vendée - 20kms from Atlantic coast.
    "The price good men (and women) pay for indifference to public affairs is to be ruled by evil men (and women)."
    Plato
  • WilderbeastWilderbeast Posts: 1,415
    The real nasties that used to be used for treating wood were banned years ago so you needn't worry. The flip side is that treated wood no longer lasts anywhere near as long, so much so I now refuse to fit treated soft wood decking as it has such a short life 
  • FairygirlFairygirl Posts: 55,117
    It's not worth installing anything made from timber unless it's good quality, treated stuff. It's perfectly safe.
    Anything that's going to contain plants, of any kind, needs lined to help with the durability and also for water retention if the beds are raised in any way. 
    We constructed a raised deck, with adjacent planting, around two decades ago at a former house. It's all still there. 
    It's a place where beautiful isn't enough of a word....



    I live in west central Scotland - not where that photo is...
  • MerrickMayfairMerrickMayfair Posts: 13
    Thanks everyone for your replies. Just to clarify the decking is treated wood, and I would be looking to use untreated wood for building the raised beds. My concern was of any chemicals/poisons leaching out of my decking into the soil that could potentially contaminate any food I grow in the soil. I was thinking of sealing off the base of the raised beds so the plants couldn't reach the soil, and it would just contain compost and top soil bought from a garden centre. 

    The decking is large, takes up 36 square metres of the garden so a lot of treated timber is used for it. 
  • Lizzie27Lizzie27 Posts: 12,494
    Re-read Wilderbeast's post above and stop worrying.
    North East Somerset - Clay soil over limestone
  • WilderbeastWilderbeast Posts: 1,415
    @MerrickMayfair previously arsenic was used in treated timber and this was the problem chemical, it's been out of use in the UK for years. There is research out there you can look at, make sure it's UK based though as they still happily use arsenic in the US and there is loads of info on that. I'm thinking you wouldn't be able to buy raised bed lots, planting troughs and planting trugs all of which are widely available in treated timber if it was poisonous. To properly protect the bed from any leaching from ground water you would need to create a fully enclosed non draining container
  • Lizzie27Lizzie27 Posts: 12,494
    Sorry for rather terse post, I was feeling cross for some reason at the time. What I should have said is that we made 3 big, long veg beds about 3 years ago using treated decking boards and have had absolutely no problems with our veg. We're still here!
    North East Somerset - Clay soil over limestone
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