Worm Castings is a pure, single-ingredient soil improver: feeds plants gently with natural, slow-release nutrition. It is meant for enriching any mix without the risk of burning roots. Sybotanica sifts and grades every batch, so what is in the bag is consistent every single time. Use it on its own or blend it into your own mix. One clean ingredient, no fillers and nothing added Graded and sifted for a consistent particle size Mix it your way, or use it as a layer on its own Resealable bag that keeps the rest dry The building blocks serious plant people use to build a substrate that fits their own conditions.