Could be that you had egg casings left in the castings, and they hatched and grew?

Carol

Carol, I don't think that is the case. The fresh castings I observed were about 1/2 inch high and probably too large to be from baby red worms. Plus the worms I did see (when I pushed aside some of the castings) were fully grown. The weather has bee very cool and wet here too so I'm not sure if any cocoons (from my old castings) would have been likely to hatch.

Harry

yes, that makes sense. :)

I think worms can smell their own, and castings are quintessential worm funk. Also true that eggs are invariably in the castings. I've noticed some worms in my bins which are iridescent. They are invariably fat and lively fellows.

Is this like The Last Dragon, when Bruce Leroy gets the glow?

Sounds like you just had some deep dwellers come up to check out that strange new odor in their neighborhood. Kinda like a new girl cat arriving in an established pecking order.... brings out all the other cats to take an assessment.