"zxcvbob" wrote in message
...
I was looking at lumber for building raised beds in my garden. I was
planning to use untreated 2x6's for the sides and ends, and pressure
treated 2x4 stakes in the corners and joints. (I would use creosoted
2x4's
if I could find them.) I live far enough north that I don't have to worry
about termites.

Home Depot has some new pressure treated lumber that's supposed to be
non-toxic; it's treated with ACQ instead of CCA. "Alkaline copper
quaternary." Has anyone heard of it? I haven't bought anything yet
until
I do some research.

-Bob

Bob
Things you should be aware of with the new ACQ lumber.
1. There are different grades of it. You should be looking for wood labeled
for ground contact.
2. The copper will corrode galvanized or zinc plated screws and nails. If
you expect it to last you will need stainless steel hardware or at least
double dipped galvanized.

Does anyone here know at what level copper is toxic to plants?

Boron treated lumber is another alternative but in high levels boron is also
toxic to plants.

Personally with all I have heard about the new PT lumber I will wait until
more is known about them.

Bill