Cyanobacteria has a highly diversity group that consists of photosynthetic prokaryotic microorganisms. Cyanobacteria that produce lots of metabolites such as amino acids, proteins, vitamins etc. have a wide spread. In this study, the effects of different concentrations of Spirulina platensis extracts on the germination of wheat and barley seeds and root-stem length, lateral root number and fresh-dry weight were investigated.