Tetrazolium test using concentrations of 0.075; 0.1 and 0.5% during 6 hours of coloration at 35 °C was efficient to estimate the viability of S. gardneriana seeds. In other periods, regardless of the temperature, tetrazolium salt concentrations did not promote an adequate coloration that would enable to distinguish living from dead or damaged tissues. However, lower concentrations are more indicated by their lower salt cost and due to allowing a better visualization of the coloration disorders and identification of different types of injuries (AOSA, 2009). Thus, tetrazolium test using a concentration of 0.075% can be used as a supplement to the germination test in assessing the viability of S. gardneriana seeds.