"Earthworm" is the common name for over 2,500 species of Earthworm. But not all species are suitable for vermicomposting or the compost bin. Earthworker worms do not eat a large volume of organic material, do not reproduce well in confinement, and do not thrive when their burrow systems are disturbed. Vermicomposting worms on the other hand, reproduce quickly, eat large amounts of organic material, and tolerate disturbance.
Red wigglers are the most common type of vermicomposting worms. They are rust brown in color with striping between segments. Adults can grow to about 3 inches in length, they prefer temperatures between 59-77 degrees F, and cocoons hatch between 35 and 70 days. Red wigglers work well for vermicomposting because of their high reproductive rate, ability to survive in varying conditions, and because under perfect conditions, they can eat their body weight in food everyday. Red wigglers are not soil dwellers and will likely perish if added to a garden.
The tiger worm is a close relative of the red wiggler and shares very similar vermicomposting abilities. They are dark red or purple in color and can grow up to 3 inches long. They prefer temperatures between 64 and 72 degrees F and can process large volumes of organic material. They are often not separated from red wigglers by commercial growers.
This worm works well for vermicomposting and bait as well. It is said to be irresistible to fish. This worm is dark red to maroon in color with no striping between segments. They can grow up to 3 inches in length and prefer temperatures between 64 and 72 degrees F. Redworms cocoons hatch in 12 to 16 weeks. This worm can potentially do double duty as a vermicomposter and earthworker.
Nightcrawlers are not ideal worms for vermicomposting bins. Nightcrawlers are deep dwellers that can burrow up to 6 feet into the ground. Nightcrawlers do not like their burrows to be disturbed and prefer temperatures around 50 degrees F. They can grow up to 12 inches in length and prefer to eat leaf litter and mulch. Nightcrawlers are earthworkers, performing an important role in soil mixing, taking organic matter from the surface into deeper layers of the soil.
For more information on worms, please check out The Worm Book by Loren Nancarrow or Worms Eat My Garbage by Mary Appelhof (available at the Solana Center). For a list of worm retailers in the San Diego area, please click here.