I bought several pileas from the Sill in the spring and they've were all thriving over the spring and summer. I've noticed that over the past few months, they've been dropping leaves from the bottom of their stems. Usually the leaf turns yellow, develops a brown spot in the middle (shown in picture) that grows, and then the entire leaf become brown and it falls off. I'm worried because leaves seem to be dropping one after the other in this manner from the bottom up and my plant is looking pretty bare.
I don't think I've changed my care habits since the summer, so I'm pretty stumped. The pileas are still in the same spot - right next too a West facing window, and I allow them to dry out between waterings. They are up near a window so I'm wondering if the cold has anything to do with this? I did get them in the spring so I haven't cared for these plants in the winter yet. Any help would be amazing! Thank you so much :)