Fertilome Ultimate Potting Mix Is A Must Have For Every Gardening. This potting soil stays light and fluffy while it still holds on to water. Your plants will be happy living in Ultimate Potting Mix. Use this Potting Mix in all container gardens or add it to your plantings. Be sure to dig the hole larger than the root ball and mix some of the existing dirt with the potting soil to backfill. Contains: Sphagnum Peat Moss, perlite, wetting agent and slow release humic acids. 25 Quarts.