In certain agricultural species, particularly in perennial legumes, optimum germination capacity in seeds is strongly influenced by the share of hard seeds. This seed category can germinate in a certain share, after a longer period, depending on environmental conditions. Research show that, after a period of six months, hard seeds germinated differently, depending on their size: 71% in the seed group that was not selected depending on size, 35% in small seeds, 67% in medium seeds, and 57% in large seeds. After 266 days of germination, and after previous treatment with ultrasounds, they showed a germination capacity between 46.9% and 68.9%.