I've used worm poo twice now in the potting mix. Plants seem to like it, especially noticed on transplantings...no shock. it will last your entire grow.

i think of it more as an amendment to potting soil than food, because it's much lower in N than the plants will want and can take for regular feedings, so no need to worry about overkill with worm castings.

My potting mix is supersoil, perlite and wormcastings only. Drains well.