The great worm debate

Credit: istock/LawrenceSawyer

The blue Hawaiian worm (Perionyx excavatus) has been of interest recently as a worm suitable for vermiculture. It is a 2.5 to 7.5 cm (1 to 3 in.) long earthworm that is deep purple on the front and red or brown at the rear, an iridescent blue sheen over its skin. Native to tropical Asia and a prolific breeder, it has naturalized in Hawaii. Since it is adapted to subtropical temperatures, it’s ideal for warm composting bins and is an excellent composting worm. That being said, I discourage readers from introducing it to our area. It’s unlikely to survive our cool weather, but taking a lesson from the adaptable pine beetle, it’s best not to take chances.

For our climate I would encourage the use of red wigglers (Eisenia foetida). They are suitable for the warmth of a compost bin, can tolerate our cooler weather and are widely used and available in North America.