Yeah, I worry about humidity. Usually by having a lot of plants close together and some sitting in water (cannas, ginger, e.g.) and needing to water some plants EVERY day, they do all right. I tend to give the foliage a shower since I'm out there anyway. A couple of years ago, though, the temps got so unreasonably high without humidity that some didn't do well. But neither did any other plant or myself. It wasn't nice.
