As the growing season ends, cleaning your urban planter boxes is a crucial task to prevent disease and prepare for a successful garden next year. Start by removing all old plant material, including roots and stems. Dispose of diseased plants in the trash, not the compost. Next, empty the old soil onto a tarp. You can refresh this soil by amending it with compost for reuse, or discard it if plants were unhealthy.
Thoroughly scrub the empty planter box with a solution of one part white vinegar to nine parts water or a mild bleach solution (one part bleach to nine parts water). Use a stiff brush to remove all debris, mineral deposits, and algae. Rinse the box completely with clean water and allow it to air dry fully in the sun, which helps disinfect it.
Once dry, inspect your planter for any damage and make necessary repairs. If storing the planter over winter, ensure it is completely dry and store it in a sheltered location like a garage or shed to protect it from freezing and cracking. For planters left outside, consider covering them to prevent water accumulation. Taking these steps now will give your plants a clean, healthy foundation for vigorous growth when spring arrives.