Earthworm Composting: Worm composting is the decomposition by a type of earthworm called  RED WIGGLER Eisenia fetida which eats your organic raw food waste and leaves rich compost and a liquid fertiliser in return. Worm Castings Worm castings are the richest form of natural fertiliser known to man. It promotes ahigher than average growth in plants (ideal to start seedlings, when mixed withpotting mix or as a top-dressing around plants).