Which worm is best for composting?

Different composting worms

At Worms Direct one subject that comes up with our customers time and time again is “which composting worm is best” this question arises due to the amount of confusion that has been generated over the years by companies selling worms and pretending they know all about worms and just repeating what others have written! some will quote scientific studies completely out of context, hopefully we can clear away some of this confusion.
First it is important to understand that different species of worms are not available in different countries, therefor you will often see, particularly on forums, that such and such worm is best, yes it is in their country but may not be applicable elsewhere when other worm species are available, as an example, an Indian Blue is an extremely efficient worm in hot climates but in the UK it will die, secondly, particularly in the UK common names are mostly used and have been applied to different worm species – Tiger worm is a prime example, often this is done by sellers who are not aware of the differences! so lets start from the beginning.

The most talked about worm (using a common name) is “Tiger worm” the latin name for this is Eisenia foetida or Eisenia fetida, this the most commonly used worm in the US also known as Red Wiggler and a lot of worm composting information on the internet comes from the US, it is stripey in appearance.

The most commonly grown worm for composting (and fishing) in the UK is “The Dendrobaena” the latin name is Eisenia hortensis or Dendrobaena veneta, it is also stripey in appearance and has therefore been called “Tiger worm” by many growers.

You now have the situation where 2 different species are being called and sold as “Tiger worms”

Apart from ourselves, we are not aware of anyone who is growing the original Tiger worm (Eisenia foetida) as a clean species, many growers will have them mixed in with their Dendrobaena stock.

You will then see growers claiming “Tiger worms” are best but which one? you will see growers claiming the original Tiger worm (Eisenia foetida) is the best and backing this with findings from scientific trials, I have yet to read of any scientific trials that were carried out in domestic wormeries using household waste by inexperienced people!
The truth is that both worm species work and breed better in different conditions:
E. foetida (original Tiger worm) work better in warmer bins, Dendrobaena prefer it cooler.
E. foetida (original Tiger worm) work better in drier conditions, Dendrobaena prefer it wetter
E. foetida (original Tiger worm) work better in denser populations, Dendrobaena need more space
E. foetida (original Tiger worm) are more delicate, Dendrobaena are generally tougher.
E. foetida (original Tiger worm) breed more quickly than Dendrobaena, yes, when its warmer

So you can see, it all depends on the conditions the worms will experience in your wormery, if you can guarantee the right conditions for one or other species then use that worm, if you cannot then play it safe and use a mix of both species (if you can get them). Do not be taken in by sales blurb.

I truly hope this has gone some way to clearing the confusion.