Question: Over the years that I’ve grown houseplants, I’ve had many that dropped leaves soon after I got them home. What, in general terms, causes that?

Answer: A change of lighting, generally to lower light intensities. The plants had adjusted to certain levels of lighting in their nurseries and greenhouses. When you brought them home and put them in your own environment, they didn’t get those same levels of lighting. If the leaf drop happened somewhere around the 2 to 4 week mark, it’s the change of lighting almost assuredly. Letting a plant get too dry between waterings can also lead to leaf drop, and so can certain insect outbreaks.