Abstract: Melissttus ruthenicus is a perennial legume and one of the most common fodder plants in northern China. It is a wild, high-quality forage grown mostly for hay, green forage, silage or seed production. However, seed hardiness is a major problem in the seeding of M. ruthenicus. This study evaluated the simple empirical relationship of time and seed hardiness by simultaneously analyzing pod and seed morphological and physiological properties. Pods were harvested at three-day intervals from the 9th day after peak anthesis (DAPA) until pod shattering. The pod and seed both lost green color and turned brown from the 33rd to 36th DAPA. The length, width and thickness of pod and seed differed significantly between sampling dates. Pod length and thickness declined significantly at the 33rd DAPA. Seed length, width and thickness significantly decreased from the 33rd to 36th DAPA. The fresh weight of pod and seed increased at an early developmental stage but decreased markedly thereafter. However, the dry weight of pod and seed increased significantly with sampling dates and reached a maximum at the 27th DAPA, then stabilized from the 27th to 36th DAPA (pod dry weight) and the 30th to 36th DAPA (seed dry weight). The water content of pods and seeds decreased significantly over the sampling dates and reached about 20% at the 33rd and 36th DAPA respectively. Seed hardiness occurred at the 33rd and 36th DAPA when seed water content was about 20%. There was a significant negative correlation between the percentage of hard seed and seed water content. In conclusion, growth stage and seed water content affected the occurrence of seed hardiness. Pod and seed morphological and physiological properties could be reliable and rapid indicators of seed hardiness, providing a simple way to judge the occurrence of seed hardiness. However, the dry weights of pods and seeds could not be used as indicators.