Yes, Physan helps a LOT I think. I spray the whole cage after the power-washing gets done, screens, supports and pavers.
I have sprayed the pavers in the cage a couple of times this summer and have much less green goo growing on them now. What with rain, humidity, misting every day under the orchids and also spraying fertilizer around in there, the moss and algae just loved it under my orchid area.
Last year I was spraying all my orchids with it, too, once the black rot started showing up. I've stopped doing that, but honestly don't think it did the plants any harm, and may have helped some of them survive. This year, I have not had hardly a black spot showing up! Partly the sanitizing, but mostly I think it is the drier weather we had in July.
