Latest publications indicate that Cyanobacteria and green algae can play an important role in symbiosis with other organisms and can produce active compounds (classified as secondary metabolites) that inhibit the growth of pathogenic bacteria and fungi and increase plant growth. Some strains of Cyanobacteria can also assimilate atmospheric nitrogen, which enriches the soil and then is taken up by plants. Due to the lack of information concerning their application in energy crop production, the aim of the presented research was to evaluate the possibility of increasing growth of corn seedlings by grain conditioning and root application with Cyanobacteria and green algae. The obtained results show that monocultures of Microcystis aeruginosa MKR 0105, Anabaena sp. PCC 7120 (Cyanobacteria), and Chlorella sp. (microalgae) significantly increase germination and growth of corn seedlings and also intensify some metabolic processes.