might be the low temps. mine bloom daily when its hot, and lots of sun. it could also be a change in its environment (going from the outside to inside your house).

i would not water more than once per week at most. once every 2 weeks should be ok. depends on the humidity/temp in your home, soil's water retention, how much moisture the roots are absorbing. just check how dry/moist the soil is once a week. water accordingly.

any regular fertilzer like miracle gro is fine. i like to mix it at half the recommended ratio. if its one scoop per gallon of water, i go half scoop per gallon. fertilize about once a month during the growing period (spring & summer).

Thanks - I'd like to move it outside once it gets warmer here. I'm assuming it shouldn't experience temps lower than about 60 at night?

it can survive pretty cold temps, i bring mine in when night temps drop into the 40's.

but for blooms it needs to be warmer.

Here's a tip I've learned after experiencing the bud drop problem with my potted Hibiscus plants over several summers: Do NOT turn your pot while your Hibiscus has buds. If you turn the pot to promote more even growth on all sides, your Hibiscus will drop its buds! I guess this is because the heavy buds are forced to grow in a new direction toward the light/sun, and this causes the bud stems to bend and there go the buds. I've been told to wait to turn the pot until there are no buds or only very tiny buds. If you must turn pot with large buds, turn it only 1/4 turn a day. This tip has helped me -- hope it helps you too. Of course, any environmental stress bothers Hibiscus. They like acid soil; just the right amount of water and fertilizer and temps. It causes them stress just to be relocated to your home from a nursery and/or being repotted. I live in the deep South, and my Hibiscus pots must be shaded from the scorching noon to 3PM sun. They are unhappy when it's 100 degrees here with 100% humidity, but then so am I! Good luck with your Hibiscus!

I wonder if 20+ mph west texas wind is breaking the unopened bloom off.