Biostimulants (BS) are a new category of crop fertilizer products stimulating plant nutrition processes independently of the product’s nutrient content, with the aim of improving a) nutrient use efficiency; b) tolerance to abiotic stress; c) quality traits or d) availability of nutrients for plants. The European BS markets are growing and BSs are expected to become an essential tool for farmers. BioLantti project supports Circular bioeconomy when added value is created by using under-utilized raw materials as feedstock for BSs according to cascading principles. Efficacy testing requirements for BSs are just being created at the EU. Our goal is to develop a testing protocol in Luke that supports regulation, product development and commercialization of BSs.