Question
Would you know if it is safe to use treated timber to build raised veggie gardens, will the timber contaminate the soil & veggie's, Thanks, Roy.

Answer
Roy:
Great question. I have done a good bit of research on this topic in order to help with two major community gardens I designed and helped build here in Georgia. We could not find any reports of the modern pressure treatment chemicals causing any measurable levels of chemical increases in the edibles parts of tested vegetables. There were a couple scientific papers that showed minute, non-dangerous levels of leaching into the soil directly adjacent to the wood on very fresh wood. It is advised to let freshly pressure treated wood set in the sun for several weeks and to scrub it off before using. Also I can attest to the fact that there are a large number of well respected local community gardens in Atlanta that use modern pressure treated pine. Now, all that said, no matter what the research shows, physically there are still chemicals in the pressure treated wood and many people still don't like that idea or even the slightest chance they could be eating chemicals of any kind. In this case cedar is the best route for a truly organic gardening experience.
If you are trying to save money consider using a plastic membrane 6mil is suitable as a barrier between your soil and the treated wood. Or for long lasting solution that will help preserve your wood, use a roll of aluminum roof flashing (obtain in roof section of local home or hardware store)they are typically available in 8"-10" and bigger rolls.

Hope this helps

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