An earthworm is an earthworm - well, that was what I thought when starting my journey to know more about earthworm farming. I quickly discovered that composting worms are not the same as common garden worms.
As a matter of fact, I should not be using the garden worms at all.
And the reason is because of their different worms for different causes. You will find the Earthworker, the Root dweller and then of cause the Compost worm - the one I am interested in. They live in the first 12 cm of topsoil on a rich diet of rotting vegetable matter, but they don't eat soil - you won't find them in normal garden soil.
Just as I thought I got it under control, it came to my attention that there are 4 species of compost worm.
Luckily the literature and opinions of the experts agree in their recommendation that the Red Worm (Eisenia foetida) is the one to own.
Red worms are nature's ultimate composting worm and a great pick for worm farms. Red worms go by many names. They're often called red wigglers, tiger worms, manure worms, composting worms, and the trout worms. Whatever you call them they're among the best composting worms available.
Unlike your everyday night crawlers, they live well in close, highly populated conditions and don't burrow. In nature, you would almost never find a red wiggler worm heading deep underground. They are very good at producing worm castings and can eat up to their own body weight a day under ideal conditions.
Another reason that raising red worms is easy is that they breed exponentially.
In ideal conditions, they will reach sexual maturity six weeks after hatching. Once mature they will reproduce every week producing a cocoon which will contain 3 to 7 worms. In a nutshell, your population of worms will double every 6 to 8 weeks. A thousand red worms can easily reproduce to a quantity of over 1 million within two years. This would depend on them having enough food, space and good living conditions.
Sources:
https://www.omlet.co.uk/guide/worm_composting/about_worms/earthworm_types
http://home.howstuffworks.com/vermicomposting1.htm
http://www.worm-farm.co.za/red-worms-for-sale.html
http://www.wormfarmfacts.com/Red-Worms.html