A gardenia carrying buds is a tempting plant to fuss over. More feeding, a larger pot and a move to a better view may all seem helpful, but doing them together makes any resulting problem hard to understand.
Begin with a stable position that meets the plant's needs. Check the root ball regularly and avoid swings between prolonged dryness and saturated compost.
Keep a short record
Note watering, feeding and changes in room conditions. If buds begin to fall, that history is more useful than guessing which product might bring them back.
Look for other symptoms. A plant losing leaves, showing pests or sitting in a wet outer pot needs a different investigation from one with otherwise sound foliage and a few ageing buds.
Do not repot solely because buds have appeared. If the container has a genuine problem, deal with it carefully; otherwise, consider whether that job can wait for a more suitable stage. Flowers already developing are a reason to observe closely, not an instruction to increase every part of the care routine.
Related reading: Gardenia Flowering: Timing, Buds and Common Problems.