How to Make a Plaster Pot Waterproof

Put on a pair of rubber gloves to avoid transferring the oil on your hands to the plaster surface.

Wipe the surface of the plaster clean with a tack cloth. Remove any stubborn marks with a white pencil eraser. If the plaster pot has been heavily handled and is quite soiled, wipe the surface with a clean cloth dampened, but not soaked, with mineral spirits.

Pour epoxy into a disposable container. Most epoxies come in two parts that must be mixed together at the ratio dictated by the manufacturer. Stir vigorously with a disposable paint stick until the parts are thoroughly mixed.

Stand the pot on its base. Apply one coat of the epoxy sealant to the inside of the pot with a foam applicator brush, according to the manufacturer's instructions.

Allow the sealant to dry for one hour.

Flip the pot over onto its lip. Paint its outer surface with epoxy. Plug the inside of each drainage hole with a cotton swab. Do not allow excess epoxy to clog the hole.

Allow the sealant to dry for the recoat time—the time that must elapse before you can apply a second coat—listed by the manufacturer (usually around six hours). The recoat time will be listed on the epoxy's packaging.

Repeat steps three through six to apply a second coat to the pot.

Allow the pot to cure for the manufacturer-recommended amount of time (usually 36 hours) before placing a plant in the pot.