Premium All Purpose Potting Soil, 1.5 cu. ft. Bag This professional-grade blend from Proven Winners comes in a 1.5 cu.'. Bag. Blend of 50-60% Canadian sphagnum peat Moss, processed softwood bark, perlite, dolomite lime, a controlled release fertilizer, and a wetting agent. Specially formulated to produce vibrant flowers and strong growth Medium-weight mix with excellent air porosity and drainage Canadian sphagnum peat moss Processed softwood bark Horticultural-grade perlite Dolomite lime Professional wetting agent