Remove any dirt or debris from the surface of the flowerpot, using a soft cleaning cloth and an ammonia-based cleaner. Buff the flowerpot dry with a second cloth.
Give the entire surface of each flowerpot a light sanding with fine-grit sandpaper. A light sanding to rough up the surface of the resin or fiberglass is all that is necessary.
Set the flowerpot on a stable surface in a well-ventilated area. Protect the surface with a tarp, old sheet or several layers of newspaper.
Shake the spray can for two to three minutes and begin spraying, holding the can approximately 8 inches from the flowerpot. Spray one pot at a time, using steady, quick bursts. Continue spraying until the pot is coated with a thin, even coat of paint.
Wait 30 seconds and then apply a second coat of paint, if necessary. Allow the flowerpot to dry for a full one hour before use. Plastic spray paint dries to a hard finish within seven days of application.