Bruce (Bendback50) knows what he's talking about and is absolutely correct that P. hawayana and A. gracilis are one and the same. This is not opinion, but fact. Earthworms are often re-classified when it is discovered that their physiology more closely resembles a different group or when new families or genera are added to the taxonomic lists. A. gracilis is a species that has been caught in this re-classification loop on more than one occasion, thus it is known by many names, most of which are outdated. The current correct name is Amynthas gracilis. Stay tuned, however, because getting taxonomists to agree and settle on a classification is akin to hearding cats...

There is no one worm type or species that is generally "best" for buliding soil. While we break them out into the categories endogeic, anecic and epigeic, most worms have characteristics similar to those of the other categories. For instance, Lumbricus rubellus is categorized as an epigeic worm and performs and grows best in surface debris, but it can and often does burrow surprisingly deeply. The defining lines between species categories are not firm, but are rather blurry in many cases.

It takes worms from all categories working in all areas of soil to maximize soil health. Determining whether an epigeic or endogeic species is best for you soil at a given point is akin to trying to determine which came first, the ckicken or the egg. Endogeic worms feed in soil that has decayed OM worked into the matrix; epigeic and anecic species decay that surface debris so it can be worked into the matrix. Which should come first? That is a question only the worms can answer. It is for this reason that adopting the "if you build it they will come" approach is usually the best idea. Create conditions suitable to worm activity; keep the soil well mulched and moist, avoid chemicals and tilling where possible, and the right worms will arrive at just the right times.

Lastly, and most pragmatically, there are no sources of endogeic worms for sale, and even if there were, there is no guarantee that the species being sold would be appropriate to your particular soil type.

So, mulch, mulch, mulch, get roots in the ground (plant roots encourage soil biology), avoid disturbing the soil as much as is practical, and let the worms do what worms do!

Make sense?

Kelly S

Yes, what Kelly says makes since, just let nature make these hard decisions. One reason for my question is that I'm starting with pretty much a clean slate as far as my Tucson garden is concerned. It needs as much help as it can get. In preparing the garden, turning over the soil in the two shovel method, I have never found an earth worm of any variety. And the turn over method is really a pick, shovel, pick shovel method.

So now I have red worms in my compost which will be added to the garden. Maybe I should try a few night crawlers in the garden soil. Have you heard of Dillie worms. Look to me like short night crawlers which would put them in the anecic class if I have learned something from Kelly.

One more question if I may - have you ever heard of one type of worm eating another? Maybe just the eggs?