There is some studies about BSF castings as fertilizer – apparently it combines well with wood ashes. We see that insect frass quality dramatically depends on the food input in terms of composition – esp. if there is a surplus of unconsumed food that is pelleted with the frass. Then the values can hit fantastic values. BSE are often reared on “not so nice” food for hygienisation of waste, so do ask what they are fed with.

In general mealworm frass is safer as their usual diet contains a lot of chaff.

The chitin component is very interesting esp. in presence of AM fungi, that directly (weeks) deal with the nitrogen for carbs.