This study was conducted to explore the effects of seeding rate of a seed mixture on grassland productivity and botanical composition. Seeding rates were composed of four different treatments varying by the amount of seed: T1, 50% decrease in seeding rate from standard; T2, standard seeding rate; T3, 50% increase in seeding rate from standard; and T4, 100% increase in seeding rate from standard. In 2016, seasonal changes in grass botanical composition revealed T2, T3, and T4 in portion of grass ratio were the highest with a range of 87–100%, whereas T1 was the lowest of all treatments. In 2017, the botanical composition in T1 showed that the grass ratio in of the first cutting was 91%, but in the fourth cutting its ratio decreased by 75%. The results from both years were combined for each treatment, T4 (11,435 kg ha-1) and T3 (11,162 kg ha-1) demonstrated the highest dry matter yield of the treatments (T1: 8,196 kg ha-1; T2: 9,521 kg ha-1) (p<0.05). As a result, a 50–100% increase in the seeding rate from the standard demonstrated the best grassland yield and botanical composition.