Place under a dome or in a tank to keep humidity high or move outdoors. This should help immensely.

Thanks, McDole. Guess I never considered putting them in the 100° Texas heat as a better option. Of course I'll put them in shade, but even the local nursery I buy some begonias told me she lost a lot last year because she couldn't keep her greenhouses cool enough. But it's worth a shot!

I have mine in 94 degree shade and they all have responded nicely. What's six more degrees? Greenhouses can be very hot if they don't have some fans running and shade cloth up. A lot of greenhouses have chillers in them but it's hard to tell at times. I've been in PHOE's GH and the Huntington conservatory where the heat and humidity almost made me nauseous but the plants (and begonias) apparently loved it.

Well after about 2 weeks of having my Rexes outside, they DO seem to be doing better with new growth on a lot of them. Thanks for the tip. The past couple of weeks have given us days of 60% and higher humidity. I'm now certain that the A/C was removing all the moisture from inside.