Instead of sand I use eggshell powder for the same effect . I do it with a coffee grinder .don't forget sand*.
worms have a gizzard like chickens and use the sand to help them digest.
You can give them banana to have phosphorus and potassium . Worm like banana !I wonder what would happen if you fed your worms food scraps that are high in Phosphorus & Potassium.
Seems like it's very possible to tailor the worm castings to match the flowering requirements of our favorite plant.
Collembolans are omnivorous, free-living organisms that prefer moist conditions. They do not directly engage in the decomposition of organic matter, but contribute to it indirectly through the fragmentation of organic matter and the control of soil microbial communities.