porch. Filled it with mulch and put in concrete pavers for the walkway. Then started planting shrubs and flowers inside the timbers and around the border of it. Made sure they were far enough away from the dogs MAIN area of use. Also put in a concrete fire hydrant for the male dog! Works great, no yellow spots. In the fall we also mulch leaves to put on top then wood mulch on that. Someone told me they decay of leaves helps to keep the smell down, it does work. Also I use the bed for starting shrub cuttings. Everything thrives in the soil. Maybe this will help others with the yellow spot problem. Have not put a roof on the back porch yet, thus the umbrella for the dogs.