If you are looking for non toxic longevity why don't you look into composite
lumber for your raised beds.

Val
"SteveB" wrote in message
news
I have decided to make some raised planting boxes rather than go into the
earth, which here is a combination of sand dune sand and caliche. I
believe that some treated lumber would last the longest, or perhaps some
railroad ties. Maybe some old building beams if I can find them for a
decent price.

Is there a danger of the chemicals leaching out from treated lumber or
railroad ties for garden beds? What if I put a liner? I intend on going
to the nursery, and getting a really good mix of soil delivered, or maybe
just getting some bales of peat moss, and some bags of soil and mixing.
But I don't want to do all the work and spend all the money if I am
planting these things in a toxic box.

TIA

Steve