Ooops. Castings.
Yeah, my mistake: It’s “castings”. (eye roll)
I should try mixing some from a 5 gal bucket I use to put worms in with some moist leaves our chickens have shredded up. If the worms, esp. jumpers, are in there for long, you end up with nothing but castings and maybe the last couple worms, dead & rotting. Mix that with peat or shredded leaves from trees that don’t produce juglone, and a bit of river sand (free for me, 5 gal bucket-at-a-time, if I want to drive over there). I’d think that would make very “nutritious” garden soil.