Plant growth studies involve seed germination studies and this depends on storage viability and dormancy aspects besides essential requirements and factors for the same. Of the various factors regulations plant growth and developmental processes intrinsic factors play a significant role. Plant hormones are chemicals that regulate plant growth. These occur in extremely low concentrations and influence all developmental and physiological processes in plants. The effect of different concentrations of GA3 on seed germination of Tithonia rotundifolia Blake was studied. The maximum percentage of seed germination was at 500 ppm GA3.