Q: My Christmas cactus had many buds, but lots of them fell off without opening up. What am I doing wrong?
A: In my experience, there are three things that could cause Christmas cactus bud drop. If the plant is moved from a sunny window to a dimmer spot, the plant won’t receive the energy it needs to fully develop its flowers. If the plant is subjected to drafts from cold air moving down the window pane or from a nearby furnace vent, bud drop is common. If the Christmas cactus is newly arrived from a nursery, there may simply be too many buds for the plant to completely support them all. It drops buds to match the new environment. I am reasonably sure one of these three explanations fits your situation.