What does Worm Castings mean? Worm castings, also known as vermicast, are a worm’s manure in its natural form. The waste produced by worms as they eat compost, natural decaying debris in soil, and other organisms such as rotifers, nematodes, protozoans, bacteria, and fungi becomes a nutrient-rich soil additive. Worm castings contain an abundance of bacteria, remnants […]