For square foot gardening, I was thinking it might be cheaper to use
landscaping timbers that have two flat sides, drill holes near the
ends with two of them stacked, and then drive 1 in. EMT conduit into
the holes to fix them into position---- like I have seen done with
raised flowerbeds. Untreated wood would probably rot in a short time.
But what about growing veggies? What are the chances that toxins could
get into the vegetables from the lumber if it's treated? Has someone
actually tested to see if arsenic leaches out and gets taken into the
plants?