If you are planning to paint your concrete planters, consider a pair of important factors. First, because these containers are exposed to a lot of water, select the appropriate type of coating capable of holding up to high moisture. In addition, employ the correct surface preparation techniques to condition the concrete to accept the paint, or you will end up with chipping and flaking over time.
Remove all dirt and vegetation from the concrete planters.
Clean the concrete planter thoroughly with a pressure washer. Ensure that all residue has been removed, as any dust or dirt will interfere with paint adhesion. Allow the planter to dry out completely.
Move the concrete planter on top of a fabric dropcloth if possible. Cover the areas surrounding the concrete planter with fabric dust sheets if the planter is too heavy to lift.
Apply a thin coat of latex bonding primer to the concrete planter, using the 3- to 4-inch latex paintbrush. Wash the paintbrush with water. Allow the primer to dry and cure for four hours.
Apply two coats of exterior acrylic latex paint to the planter in the same way you applied the primer. Allow two hours of dry time between coats. Let the paint cure for a full day before planting.
Do not use an oil-based paint in place of an exterior acrylic latex paint. Never attempt to paint a concrete planter without coating it with a bonding primer first, or the finish will peel up over time.