All of a sudden, during a heat spell by the way, I discovered today in two begona areas of the shade pots, white molf looking stuff on top of the firt under the plants. Any idea what it might be? Looks fuzzy and when touched doesn't do anything. The dsoil is wet having just been watered yesterday, but no more than usual. It's not salt build-up for sure as I've wseen that and this is very different. What can I use to get rid of it if it's going to harm my begonias? Thanks, Kathie Kelly