Abstract: A composition for a soil additive and a method for promoting plant growth using cremation ash from the remains of a cremated, e.g., human, which avoids the disadvantages of prior soil compositions while affording additional benefits and advantages is disclosed. The soil additive comprises cremation ash and a solubilizer combined with the ash to form a mixture. The solubilizer is selected for its ability to solubilize calcium or rock phosphate. Such a solubilizer may be one of either a chemical solubilizer, such as ethylene-diamine-tetra acetic acid (EDTA), or a biological solubilizer, such as composting material. The disclosed composition and method provide a way for memorializing deceased loved ones, such as, for example, family members, friends, and pets.