When should I bring in my rhipsalidopsis gaertneri, so that is could start forming buds? Could I put it in the closet all day or do I have to give it light?
rhipsalidopsis gaernteri (schlumbergia gaernteri) is a spring cacti and over here is called the easter cactus, flowering usually around March/April time; (it may be different where you are )
There is no need to put it in the closet, in fact I find that good light is best and buds should form whether it is outside or indoors; over here of course, its usually indoors due to the weather. The one thing, don't move it once it buds or they will drop off. At this time they are very sensitive to light and position changes.
I am not sure of the minimum winter temps where you are but if it drops below 55 deg f at any time of the day, I would say bring it, it wont hurt it. As I said, give it good light from the start and dont move when in bud...enjoy your cacti, they are lovely.
Mark,
I have a couple of those, but can't tell you how to handle it where you are as mine stay outside all year round. Sound like taliesin got you covered either way.
Daiv
All Cacti are succulents, but not all succulents are Cacti