We use the word vermi-casting when the focus is on earthworm castings production as with Fertilis Earthworm Castings; vermi-composting when referring to waste management; and vermi-culture when referring to worm growing.

In both vermi-casting and vermi-composting, the earthworms live in dead and decaying plant or animal waste – in fact, any biological organic matter that was once living but is now classified as waste. The micro-organisms, e.g. bacteria, fungi, protozoa, and pathogens that are present in the waste are the primary food source of the earthworms and NOT the waste itself. The earthworms move through the waste, ingest, digest and excrete it – all for the micro-organisms.

Earthworms are unique because they have no immune system, and therefore never carry disease nor become infected. They destroy pathogens and digest them to grow their own bodies. Pathogens usually require an oxygen-free (anaerobic) environment, whereas the environment created by earthworms is oxygen-rich (aerobic). This is why true earthworm castings – vermi-castings - are very low in disease-producing bacteria. Substantial reduction of pathogens also occurs as a consequence of the beneficial micro-organisms created by the earthworms in the environment around them, i.e. earthworms do not need to physically eat every single pathogen – the pathogens just cannot survive around the oxygen-rich earthworms.