poinsettia plant

Question

Why do poinsettia buds fall off? We only had 4 buds – one is blooming, 3 fell off as buds.

Answer 1

What are generally regarded as flowers on poinsettia are actually leaves. Their flower buds are very small.

Regardless of whether you meant flower buds or the distinctive red leaves, there are many reasons they can fall and all are related to stress. This time of year, I would suspect the likely culprits are either the plant is underwatered or is being exposed to a mild chilly draft.