Wormy FACTS and Interesting Tidbits (By Rhonda Sherman)
- What is vermicomposting?
Earthworms and microorganisms convert organic materials to a beneficial soil amendment.
- Can any type of earthworm be used for vermicomposting?
Only epigeic species are suitable for vermicomposting.
- Aren’t all earthworms the same?
No, there are over 9,000 species of earthworms, ranging in size from half an inch to 22 feet long.
- What species of earthworms are used for vermicomposting?
Only seven species have been identified as suitable for vermicomposting. One species, Eisenia fetida, is used by most people throughout the world. Eisenia fetida is commonly called red wiggler, in addition to several other common names.
- I’ve seen this spelled Eisenia foetida; which is correct?
Eisenia fetida is the correct spelling for this species of earthworm. Earthworm taxonomists changed the spelling from ‘fetida’ to ‘foetida’ for awhile, but then changed it back to ‘fetida’. That is why you see it spelled both ways, but ‘fetida’ is now the correct spelling.
- Where do I find Eisenia fetida earthworms?
In nature, Eisenia fetida is found in moist, organic-rich environments, such as livestock manure or under logs in the woods. Since you won’t know for sure what species of earthworms you have found, you should buy Eisenia fetida from a worm grower.
- How many Eisenia fetida do I need to start a worm bin?
You should start with at least 1,000, which will weigh about one pound.
- Where do I buy Eisenia fetida earthworms?
Since you need at least 1,000 earthworms, do not buy them from a bait shop because they usually sell 12-30 earthworms per cup. Instead, buy Eisenia fetida from an earthworm grower.
- How much will they cost?
Worm growers will charge $20 – $50 USD for one pound of Eisenia fetida.
- How much can they eat in one day?
Eisenia fetida may consume 25% – 35% of their body weight per day.
- What will Eisenia fetida eat?
You can feed them most types of organic matter that are not high in salts or ammonia. For information on vermicomposting at home, go to the Vermicomposting For Households page. If you are interested in larger-scale vermicomposting, go to Vermicomposting For Businesses, Farms, Institutions, and Municipalities.
- Do earthworms have eyes?
No, instead they have receptor cells that are sensitive to light and touch. These cells allow earthworms to detect different intensities of light and to feel vibrations. They will move away from light, if they can. If earthworms are exposed to light for too long (about an hour), they will become paralyzed and die when their skin dries out.
- Can earthworms smell?
Instead of noses, earthworms have chemoreceptors in the anterior region that react to chemicals.
- How do earthworms breathe?
They do not have lungs; instead, they breathe through their skin. Their skin needs to stay moist to allow the passage of dissolved oxygen into their bloodstream. They coat their skin with mucus and need to live in a humid, moist environment.
- How do earthworms move?
They have groups of bristles (called setae) on each segment that move in and out to grip surfaces as the earthworms stretch and contract their muscles to push themselves forward or backward.
- If I cut an earthworm in half, will it regenerate into two earthworms?
No. The half with the earthworm’s head can grow a new tail if the cut is after the segments containing vital organs. But the other half of the earthworm cannot grow a new head (and all of the other organs needed to sustain the earthworm).
- Which end is the head?
The head is at the end closest to a swollen band encircling the earthworm. Although they can move forward and backward, they tend to move forward most often.
- How do earthworms eat?
They have tiny mouths and no teeth, so earthworms eat differently than you and I. An earthworm will push its pharynx (throat) out, grab microorganisms and little bits of organic matter, and pull them into it’s mouth. The food is coated with saliva, pushed down the esophagus into the crop and on to the gizzard, where it is crushed and ground apart. Next, it moves into the intestine, where food is broken down more by digestive enzymes. Some of the food is passed into the bloodstream for use by the earthworm and the rest passes out the anus as castings (worm poop).
- What is the swollen band near the head called and what is it for?
It is called a clitellum and it contains eggs and sperm for reproduction.
- How do earthworms reproduce?
Earthworms are hermaphrodites, so individuals have both female and male reproductive organs. They mate by joining their clitella and exchanging sperm. Each earthworm will form an egg capsule in its clitellum and pass it into the vermicompost 7 to 10 days later. The egg capsule is golden-brown colored and looks like a tiny lemon the size of a match head. Two to seven Eisenia fetida babies will hatch from an egg capsule in 30 to 75 days.
- What is the difference between vermiculture and vermicomposting?
Vermiculture is the process of breeding worms. Growers usually pay for their worm feed, and the worm castings (manure) are often considered a waste product. Vermicomposting is the process of turning organic debris into vermicompost. Operators use a wider variety of feedstocks and make money on tipping fees and sales of vermicompost. The earthworm population usually remains stable.
- Can you vermicompost in cold climates?
Yes! However, to actively eat and reproduce, Eisenia fetida needs their bin environment to be between 59 and 77 degrees Fahrenheit (note: the temperature range can vary by climate).
Publications & Resources
- Worms Can Recycle Your Garbage (Rhonda Sherman, 2017, AG-473-18). How to set up and maintain a worm bin in your home or office to compost food scraps.