So I top dress with my work castings, I'll put maybe 2-3 cups on the surface of the soil of a plant when its 4-5 weeks old and water over it to wash nitrogen down into the soil. But if my plants are looking needy, I'll take a couple tablespoons of worm castings and put it in a gallon jug along with water and nuts, shake the hell out of it until its liquified, and water with that. I think immersion blending rabbit pellets would work just as well.