I'm looking for info & opinions concerning the use of cardboard as sheet mulch in permaculture. I read recently about concerns around fumigation and chemical residues as well as ingredients in the cardboard itself and the glue used to seal. I would really like to hear from people on this and any resources documenting this would be hugely helpful. I have read Paul's post on cardboard but I hadn't really thought too much about the whole fumigation of boxes with product in them prior to shipping.
Many thanks!