The shorter daylight hours and cooler temps in the fall will set buds.
A warm room and not watering right can cause buds to drop, or cause them to never develop at all.
I have always read that these
plants are dormant twice a year, a month in Sept or Oct (not sure which one) and also the month after flowering, and we should stop watering for a month those two times, something I have never followed.
They are best kept on the root-bound side. Re-potting,
growing in too big a pot, keeping the room too warm, or exposed to artificial lights can cause your Christmas
cactus to lose buds or not to set buds at all.
This way has always worked for me....
I always keep mine outdoors all summer where it gets about an hour of morning sun, the rest of the day it gets bright shade.
I water when the soil is dry, no matter what month it is and lightly fertilize it with each watering up until the buds appear in the fall, then stop feeding, no fertilizer again until
spring.
Sometimes I wouldn't have to water for a month when it's in
flower because the coolness keeps the soil moist longer.
While in
flower, you'll want the soil to get "close" to dry. Other times, let it dry out more. You'll need to ck the soil.
Natural light only, no grow lights, or any lamp lights nearby on at night. If you can't avoid lamp lighting, you can always cover it at night, then take the cover off in the morning.
Keep it where it will be cool though, 60 degrees or below.
I think it can do well even down to 30 degrees, but I wouldn't push it! If you have one, a spare room would be a good place, put it by a window with (indirect light) use a towel or something that you can block the heating vent with so it stays cool.
I have had mine in the 45 degree range and it was blooming it's head off!
Turn it only when the buds have reached about an inch in length, they are stronger by then at the point where they are attached to the leaves. If they are smaller, turning could cause the buds to drop as they turn their little heads in the opposite direction toward the light,
causing them to detach.
In the
spring, just resume the way you where watering and feeding before it set buds and flowered.
Susan