Hi John: I would not use cedar either because it will still leach out resin. Guess anything you have in mind should be OK and I suggest you apply a couple coats of paint before use. Paint stores have paint at reduced prices where they were miss tinted. Or failing that, I got a gallon of paint at the recycling depot for free. I used 2x4s for the frame and plywood for the sides from HD. I did use sheet insulation to protect the wormies in winter. Surely painting the bin should not influence the organic certification??? You could leave painting off if it does I suppose, but you realize the bin will last a few years less before it start crumbling.

Thank you for the response.

I will have to pass on painting the bins as the paint is broken down with moisture and time and bad ingredient for organics.

Just go ahead and use regular pine or whatever is available. It won't last forever but should last long enough.

John: FYI, my bin has been in operation since 2011. It is in my car-port at the north side of the house. I wrapped the foam (pink) insulation boards with plastic sheeting so only the posts are exposed to the compost and there weren't any missing paint visible (yet) the last time I harvested. You could attach this plastic throughout the entire bin (except the bottom if it's an FT, of course) if you are concerned about the wood.