Comment Re:But why? (Score 1) 92
Creating vermicompost on the moon may be close to impossible, so importing it would always be necessary.
The physical difference in regolith from earths soil is that it is unweathered and has very sharp shards and edges that would literally tear up the internals of any worms that might try to ingest it. Without the worms there would be no future vermicompost, so the system can not be self sustainable unless they first process the regolith to remove all the microscopic sharp edges.
You seem to be not too familiar with earthworm farming, but fact they DON'T need soil (or regolith) where they are living, breeding, digesting, and producing castings (= "worm poop"). And you don't need the worms present when you harvest the castings to transfer to your growing medium - the microorganisms in the castings is what you are after, and they do the symbiotic work with the plants (as with the humus from the original article). In fact, the typical earthworm species (Eisenia foetedia) that is most often used due to being a prolific composter, does not survive in your vegetable garden that well, since it is a species from the leaf litter in European forests. They are better off staying in the worm farm, to digest more organic material, and breed more little wrigglers.
Source: the plastic bin containing vegetable peelings, carton, and other organic materials, next to my fridge, that the earthworms seem to be thriving in. I did add some crushed eggshells to it (apparently some roughage like that is nice for them, but optional). While these shell fragments do have some sharp edges, this is probably not comparable to regolith (of which I don't have any readily at hand to test on the worms).