A partitioned planter for expandable compartmentalized plant growth includes an outer container and removable progressively smaller inner compartments. The planter provides water drainage and molded features to retain and position the inner compartments. The removable compartments each have a plurality of flat wall sections which are assembled to form a structure which contains the plant roots during growth. The wall segments also include stiffening brackets which engage top perimeter edges of forwardly adjacent wall members for additional structural stabilization.