Q: My wife and I were advised to use ACQ treated timbers when considering cedar alternatives for raised vegetable gardens. I would have thought cedar a good choice, but was told that it would deteriorate within a year given direct soil contact. So we purchased the ACQ timbers.
In retrospect, was this a wise choice for my family?
A: I’m not qualified to use the word “safe” but I recently built a bed from YellaWood. The cedar available these days has scant more resistance to rot than pine.
ACQ (alkaline copper quaternary) has not aroused any controversy about its safety yet as far as I know.
This scientific paper details one assessment of toxicity. Scroll down to the very bottom to read their conclusion (emphasis mine).