Beth,

I saw a similar three-bin system on Gardening by the Yard on HGTV. They
suggest treated lumber due to the tendency for wood to rot when in contact
with the ground. I built the 3-bin system but used untreated wood to ensure
no arsenic would leach into my compost. We have a commercial 3-bin system at
the Arboretum that is treated wood and the compost has been fine, but I
didn't want to chance it. I'll replace the wood as it rots (or let it
compost - lol).

An easy alternative is to cut 3' high fence wire in 10' strips, then use a
4' piece of 1/2" PVC pipe to thread through the fencing at the ends to hold
it in a loop. You can simply remove the pipe and move the fence to turn the
compost. Quick and easy.

A three-bin system can be made from 10 used pallets, which are often free at
building supply outlets and other places. Simply tie them with garden twine
into squares by standing them on edge. Cut the string to move the material
from bin to bin.

You can buy a pretty good commercial compost bin like the Seattle bin for
about the cost of the lumber to build a 3-bin system, by the way (about
$80). Our Seattle bin at the local Arboretum was at 160 degrees after three
days. We had to remove the lid to cool it a bit.

Good luck and enjoy composting.

Mac Knight, Master Composter
http://www.macknight.addr.com

"Beth Pierce" wrote in message
...
I am reading Storey Publication No. A-139 on composters. It
states you can use treated lumber for composting bins.
Knowing you can't use it for raised beds, I'd like to know
why it can be used for one thing and not the other. Is it
because compost is a "second stage" material, ready to break
down again in the soil and soil for raised beds is not?