We have dismantled our pool deck, it was all treated wood and was in place above ground for 20+ years. The wood was good enough to make 8 beds 12" deep. Question is, do I need to be concerned with leaching of chemicals in the very old, dry - yet suprisingly very usable wood? Beds are made 4x12, we are just filling them 4/13/09. Thanks!
If its an older wood you may need to worry about arsenic leaching out into the soil. Cover it with a thin layer of plastic. The older the wood the more chemicals that it was probably treated with.