I have been following the instructions for getting my poinsettia to re-bloom. I have been keeping it in the dark (covered by a large box) for about 13-14 hours a night, and allowing it to get sunlight during the day. I have been doing this routine for the past month roughly. I have 2 concerns. The first is that I am not yet seeing any red leaves. How long does it usually take to start seeing the colour change take place? Also, when I open the box in the morning, there is almost always 2-5 leaves that have fallen off over night. Is this normal? Or am I going to have nothing left of the plant I cared for all year by Christmas? Thanks so much!! Jennifer
There are specifics in the care, pruning, dormancy, fertilizing and as you mention withholding light from the plants.
This can be a difficult process in a home environment.
Leaf or flower bract drop could be due to temperature changes or watering issues.
This article has more information.