The leaves of my red begonia started yellowing recently. It began with the bottom leaves but is gradually spreading to the upper leaves as well. It was doing really well a month ago so I’m unsure what the problem is. I recently repotted it from a terracotta pot (which it grew in for about 4 years) to a ceramic pot and am wondering if that may be the cause. Can anyone give advice in this situation? Should I repot it back to a terracotta pot?