What type of worms for your worm composter?

When it comes to vermicomposting, not all earthworms are created equal. Of the more than 6,000 worm species recorded worldwide, only a handful can live and breed in the conditions of a worm composter. Here's which ones to choose, and why it's essential to get it right.

Why not all worms are suitable

As we explain in our guide The ecological role of earthworms, earthworms fall into several ecological groups. Ordinary garden worms (the “burrowing worms,” such as the common earthworm) dig deep tunnels in the soil and feed on earth that is already rich in organic matter: they simply can't survive in the confined environment of a worm bin, packed with fresh food scraps. Only composting worms — surface-dwelling worms used to living in leaf litter and decomposing organic matter — are suited to the job.

The three recognized species for vermicomposting

The composting worms you can use all belong to the Eisenia family. Three species stand out:

• Eisenia Andreï, nicknamed the “California worm” despite its European origins, is easy to recognize by its bright red color. It prefers fresh material but doesn't handle intense heat as well.
• Eisenia Hortensis (also known as Dendrobaena veneta) is larger and well known to anglers. More effective on tougher material, it handles temperature swings better, from summer heat to winter cold, and can be a bit adventurous during the first few days after it's introduced.
• Eisenia Foetida, the “manure worm,” is red striped with gray or yellow. It prefers material that is already well along in decomposition.

These three species get along very well in the same worm composter: over the months, one of them may come to dominate the others, simply because it's the best suited to your location, your climate, and your diet.

Discreet but highly effective creatures

These composting worms share traits that make them valuable allies. They breed quickly: starting at 8 to 10 weeks of age, a population can double every two to three months. They're voracious, able to process an amount of food scraps equal to half their own body weight every day. And they're hardy, with a life expectancy of two to four years, as long as their essential needs are met: constant moisture, darkness, and a temperature ideally between 59 and 77 °F (15–25 °C). We describe the breeding cycle in detail in our guide Composting worm reproduction.

Another unique trait: these worms have neither eyes nor lungs. They breathe through their skin, which explains their constant need for moisture, and they sense light, which they instinctively avoid — that's why they immediately burrow under the food scraps as soon as you open the lid of your worm composter.

Where to find the right worms

Contrary to popular belief, it's not a good idea to collect your worms straight from your yard unless you can identify the species with certainty: you risk introducing burrowing worms, which won't survive, or species poorly suited to the confined environment of a bin. The most reliable solution is to get identified composting worms from a specialized supplier — at Moutta Farm, we've been shipping our Eisenia composting worms for more than 15 years, as a mix of all three species, for a hassle-free start. We also describe a free alternative in our guide Finding worms for free.

Well fed and kept in good conditions, a few dozen worms can produce several hundred offspring in a single year.

Recognizing a healthy worm

A healthy composting worm is active, retracts quickly when exposed to light, and has nicely moist, glistening skin. After a certain age, you'll notice a swelling on its body: the clitellum. This paler band shows that the worm has reached sexual maturity and is able to breed — a good sign that your population is thriving and ready to grow.

Related products

Best Seller

Eisenia composting worms | 250 g of worms (approx. 500 ct.)

Packs from 8.8 oz (250 g) to 22 lb (10 kg) of worms

$15.24 €13.57

-25%

$20.32