Hi Colena,

I've never tried growing a Bougainvillea indoors, but I've heard that they will lose leaves in the winter.

Here is a link to the Bougainvillea Growers international: http://www.bgi-usa.com/bougainvillea-resource/care-maintenance-bougainvillea.php

Are you sure that you have the correct grow light? Have you been using this light for a while and with other plants? I'm always a little skeptical of grow lamps. If not used properly they can burn a plant, not provide enought lights, etc...

regardless, do not fertilizer your plant until it is healthy again. you do not want to fertilize a weak plant.

I have my bouganvillea growing inside in a South facing window. I can tell you that in the Winter, it gets very upset if the roots are allowed to stay too wet. Maybe your tree is stressing from the soil staying too wet? Good luck with it!