There were a few things we needed to consider when finding a space for our hanging garden. First, it needed to be some place that received some light. We decided we wanted low maintenance plants, terrarium friendly due to the glass planters we chose. You also need to consider the possibility for a draft from air vents or close by windows or doors. We do have an air vent in close proximity, but simply bought a $5 plastic shield to guide the air away from the plants.
Lastly, make sure you have an appropriate plan for anchoring your hanging garden. I recommend at least one anchor into a stud or masonry. I would not rely on drywall alone, unless you are hanging a single plant weighing less than 50 lbs. Drywall anchors are designed for shearing forces, not direct downward pull. Keep this in mind when finding the best location.