The presented paper verifies the possibility of using fly ash from biomass incineration in preparing growing media. The research aim was to determine the optimal amount of fly ash which can be added into growing media. Mixtures of materials with various fly ash contents were tested by a growing test and other analyses. Moreover, an impact of the effect of Vermesfluid solution emerging as a by-product of vermicomposting was analyzed. The experiment results prove that growing media with 5% of fly ash from biomass incineration are, due to their qualities, comparable to horticultural substrate which is normally sold on the market. In addition to this, a positive impact of Vermesfluid solution on the growth and vitality of plants has been proved.