Worm castings are the waste of redworms, different from Vermicompost, which is soil worked by earthworms. Worm castings are amazingly rich in nitrogen, phosphates and other minerals. It is a powerful natural fertilizer and great for house plants, gardening, potted plants, microgreens, wheatgrass & more. Add 20% mix of worm castings to soil for a perfect growth medium. USA shipping only.