Roots Organics Big Worm pure and premium earthworm castings is a distinctive natural soil amendment. Aurora Innovations earthworms are carefully tended and fed an unparalleled blend of organic and natural feedstocks for exceptional quality worm castings. No fillers, no chemicals and no tricks. Just pure worm castings. Add Roots Organics Big Worm pure and premium worm castings to any potting soil as an amendment and conditioner.