A blend of sterilized black Peat Soil, Sphagnum Peat Moss, Perlite and aged wood by-products. Fast and slow release fertilizers are added to assist in the optimum growth of plants throughout the season. Soil is checked for pH balance and adjusted. Growell Planter Box Mix can be used in planter boxes and other garden containers. Planterbox Mix is sterilized, light weight and especially formulated for Planter Boxes.