What is Worm Composting

What Is Worm Composting?
In technical terms, worm composting involves the bioxidative degradation of organic wastes via the joint action of earth worms and microorganisms. Geeky definitions aside, worm composting is simply a form of aerobic composting that involves the use of specialized worms to help break down organic waste materials. It is also known as ‘vermicomposting’, and is closely related to ‘vermiculture’ and ‘worm farming’ - although those terms general imply a great focus on the growing of the worms themselves, rather than on the waste processing and compost production side of the equation.


How Is It Different From ‘Normal’ Composting?
Aside from the obvious difference of utilizing worms while regular composting does not, worm composting is also a cooler (mesophilic) type of composting. Not only is a hot composting stage not required, but it is actually something that needs to be avoided in order to keep the worms alive (although, if the system has enough room for the worms to spread out they should be able to move away from the hot zones).

Here are some other differences:

Worm composting…
Is a ‘continuous’ composting process - materials are generally added on an ongoing basis, unlike the ‘batch composting’ approach used for hot composting
Can be done on any scale - both indoors and outdoors
Results in incredible compost (vermicompost / worm castings) with unique plant growth promotion properties - at little goes a long way!
Doesn’t require any turning of material - the worms accomplish this themselves
Can handle more moisture (again, worm movement helps to keep things aerobic)



What Kind of Worms Can I use?

Many people assume that you can use any type of worm for worm composting. This is in fact not the case. Effective vermicomposting requires the use of specialized earthworms - species that are adapted for life in and amongst rich organic waste materials, and warmer, crowded conditions. Just as regular soil worms won’t do all that well in a worm composting system (although they certainly can be found in the lower reaches of outdoor systems), composting worms don’t generally do very well in normal garden soil, unless of course a considerable amount of organic waste has been added.

Species of Composting Worm
Undoubtedly the most common species of worm used for composting is Eisenia fetida - the ‘Red Wiggler’ worm, also known as Red Worms, Brandling Worms, Manure Worms, and Tiger Worms (among others). This worm can vary widely in terms of coloration and size, which helps to explain why there are so many common names. This also highlights the important of using scientific names!

This species is incredibly versatile - it has a temperature tolerance ranging from 0C (32F) to 35C (95F), is a prolific breeder, and will readily feed on a wide range of organic waste materials (more specifically, on the microorganisms inhabiting the material, but we’ll chat more about that further down).

Another species of worm used for worm composting (especially overseas), and one that is becoming much more popular here in North America, is Eisenia hortensis - the ‘European Nightcrawler’, also known as Belgian Nightcrawlers, ENCs, and Euros. This species is a larger relative of Eisenia fetida and has similar preferences and requirements.

Interestingly enough, this is a species that has been viewed by researchers as inferior to the Red Worm in a lot of ways. It reportedly has a much lower reproductive rate, is slow to mature, and is not as effective at converting wastes into vermicompost. Many worm farmers (and others who have raised them) tend to disagree however, saying they are just as good or better.

Based on my experience thus far with keeping this species I would tend to agree. I’ve found them to be a very tolerant and durable worm (more so that Reds in my opinion), active breeders, and quite effective when it comes to processing wastes. I’m hoping to test them head-to-head with Red Worms in the near future.

Aside from these two commonly used species, there are a handful of other worms used for vermicomposting as well. Generally, they are tropical worms and just don’t have the versatility (for a number of reasons) that the above-mentioned species do - especially not in cooler regions of the world. Just so you know, two commonly used tropical species are Eudrilus eugeniae (the African Nightcrawler) and Perionyx excavatus (the Malaysian Blue Worm).