I received a very large Begonia Linda Dawn in the mail 3 weeks ago & have zero experience with begonias. She was repotted in a similarly sized 10 inch planter with drainage, watered weekly, and has a grow light. Unfortunately her leaves were browning and crispy, so over the last week I’ve started running a humidifier for at least three hours a day and it doesn’t seem to be helping the issue because she drops a leaf almost every day. There are new leaves growing but I’m afraid those will die off as well. Any suggestions on what I can do to stop the browning and leaves dropping? Most things I’ve read said it’s probably under-watering so, I’m adding a self watering system (Cowbell Plant) this week.