Gardeners choose all kinds of planters to decorate the landscape. White planter corn boxes consist of wooden materials used to form a container garden. These boxes--like all containers--capture the residues of weathering, potting soil and minerals from watering. The most important step of replanting a container lies in cleaning out potential disease and insects from the previous year.
Place the corn box in an area where bleach and dish soap won't affect landscape plants or outdoor furniture. Remove all plant debris and soil from the container.
Rinse out the inside of the container with water to remove as much dirt as possible. Mix up a 1:10 solution of bleach and water in a spray bottle. Liberally spray the entire inside and outside of the white planter corn box. Allow the bleach solution to remain on the wood for 10 minutes. Bleach sterilizes the surface to remove disease. It also loosens buildups of mineral salts that form an unsightly white crust around the inside edge of the corn box.
Mix a 1:10 solution of bleach and water in the bucket. Wear gloves to protect your hands. Dip a scrubber sponge into the bleach solution and scrub the inside of the corn box. Pay particular attention to corners and clean the outside of the container to remove weathering stains. Scrub mineral stains with the scrubber first. Use a putty knife to gently scrape hardened mineral stains from the corn box. Remove as much as possible to eliminate potential future damage to container plants through leaching.
Rinse the inside and outside of the corn box thoroughly with clean water. Apply a few drops of liquid dish detergent to the inside of the corn box. Scrub the inside and outside of the planter again to remove bleach residue and any remaining stains.
Rinse completely with clear water to remove all soap residues. Place the white planter corn box in a sunny location to dry for 24 to 48 hours or plant immediately with fresh potting soil and flowers.