This articlte is a very easy read and explores the effects of (effectively) fermenting the frass before use with different applicaton rates. This also explains why frass should not be applied over 2% - brilliant study.
Frass: Bacillus-based Biostimulant
Full article
https://www.mdpi.com/2073-4395/13/5/1258
Reference
(Fuertes-Mendizabal, et al. 2023)
Fuertes-Mendizábal, T., Salcedo, I., Huérfano, X., Riga, P., Estavillo, J. M., Ávila Blanco, D., & Duñabeitia, M. K. (2023). Mealworm Frass as a Potential Organic Fertilizer in Synergy with PGP-Based Biostimulant for Lettuce Plants. Agronomy (Basel), 13(5), 1258-. https://doi.org/10.3390/agronomy13051258
This article is open source, so hopefully I haven't made any IP infringements.
