To install an iron rod plant hanger over siding, select a location on the siding, and hold the plant hanger against the siding in the desired spot. Mark the spot for holes, and insert a pilot bit slightly smaller than screw shank diameter into a drill. Drills holes approximately the length of the screws, and align the mounting holes on the plant hanger. Screw through the mounting holes to fasten the plant hanger to the exterior surface.
To hang an iron plant hanger from a joist, find the most suitable joist with a stud finder. Drill a hole about 1/2-inch deep into the joist with a diameter smaller than the threaded part of the plant hanger. Screw the threads of the plant hanger a minimum of 1 inch into the wood to secure it tightly. Hang the plant from a chain attached to the plant hanger.
To install an iron rod plant hanger in between joists, measure the distance between the joists. Use a circular saw to cut a 2-by-4 according to the measurements. Place the block on the top of the joists, and mark the spot to screw the hanger. Turn the block over, and screw the plant hanger to the wooden block. Set the wooden block back in place, and screw it to the joists with 2 1/2-inch wood screws.