i bought some gravel boards from B&Q to increase the height of my existing raised beds.
I was concerned the gravel boards were obviously treated with something so contacted B&Q and they informed me their gravel boards are pressure treated with Tanalith E and they should be safe for raised beds and compost bins.
I did some googling and found the following on the lonza wood website.
TANALITH E timber is suitable for the construction of compost bins and for use as earth retaining structures for organic vegetable beds. The Soil Association (www.soilassociation.org) states that if the timber used for organic vegetable beds is preservative pre-treated then there are no issues in terms of organic status. If, however, the wood is treated once the raised bed has been built (brush applied preservative) then this would affect the status of the land.
so not only safe, but I can still consider my veg patch 'organic'!
I have a small back yard with timber fences all around and a timber shed.
I want to grow vegetables organically and worried about leach of chemicals from fences. I also want to build a green house to grow plants like chillies and aubergines.
I would be grateful for advice.
Thanks for the information on Tanalith. I am surprised however that some would consider lining the beds with plastic - this will break down into smaller particles eventually and probably cause a greater problem than any slight issue with the processing of the wood, surely??? Or maybe my chemistry knowledge is flawed!
Of course, if you have loads of money to throw around, you can rebuild beds every few years and not bother lining them, but then the old wood has to be disposed of.