Cyco Hydro Clay is certified as a growing media through the RAL ?Quality Assurance Association,? therefore it is a substrate approved and used for plant cultivation. Cyco Hydro Clay is tested monthly by RAL and GGS to ensure the highest-quality clay is produced. Can be used as a top dressing for plants to reduce evaporative losses, reduce algae, fungus gnats and unwanted weeds. It can also be used as a bottom drainage layer or full pot medium for potted plants, to provide adequate run off, maintain ideal rhizopheric root conditions and increase the physical stability of plants.