I jusr bought 3 different Rex begonias as an impulse purchase. I had some a few years back, off and on, and always ended up losing them in the winter to some kind of mildew disease: spots would appear and rot would spread from that point.

I want to put these in my upstairs bathroom: a window which has diffused light (stained glass window). There is a skylight above. Most potted plants do well there.

What can I do this time to forestall problems? This is not the same location where I had the other ones that died. Are they a "keep moist" kind of plant, or one I should let dry out between waterings?