It is possible to mix additives into the substrates. It depends on the specific needs of the grower which additives is used. We have to make sure the additive is of value for the plant that grows in the substrate. We usually add a basic mixture of fertiliser (PG-mix) to the substrate. We can use Dolokal to control and tune the pH-level of a mixture. On request we can add CRF (Controlled Release Fertiliser), biological fertilisers or, for example, mycorrhizas.