Larry I almost exclusively overhead water, it seems to work better for me with all the different plants. Powdery mildew is not my nemesis with zinnias it's that other fungus, leaf spot. My Profusion zinnias had it in '14 but the flowering was well so PROFUSE it didn't matter. I had Giant Purple and Lilliput this year and they were disappointing, lanky, sprawling AND leafspot. The Lilliput reseeded and bloomed again in Sept and Oct and were beautiful, a little spotting before the frost took them.
Did you have any difficulties with either fungus?
