I'm starting a small rhodo bed and have used peat moss and treat regularly with Miracid, so the plants are doing well so far. I would like to make more permanent acidification amendments by using things like cottonseed meal or agricultural sulfur, but so far the only things I see in garden centres in the London Ontario region are Miracid and aluminum sulfate, which I believe becomes toxic to plants over time. If anyone in the London region growing rhodos and azaleas knows of a local supplier of cottonseed meal or other useful soil amendment (other than peat moss) for an acid bed could you please let me know?