Seed dormancy in black gram (Vigna mungo) was studied about seed size (weight, length, width) and their impact on hard seed formation and imbibition rate during the summer and Kharif seasons at NPRC, Vamban, Pudukkottai. The seeds of blackgram obtained during the summer season showed a significant negative correlation with hard seed occurrence (r = -0.639, P ? 0.01) and a positive correlation with imbibition rate (r = 0.451, P ? 0.05), Whereas seed width had a weaker negative correlation with hard seed occurrence (r = 0.357) and a positive correlation with imbibition rate (r = 0.273). In addition, the strongest correlation was found between hard seed occurrence and imbibition rate (r = 0.802, P ? 0.01). The seed length of the blackgram harvested during the kharif season had a stronger negative correlation with hard seed occurrence (r = -0.790, P ? 0.01) and a positive correlation with imbibition rate (r = 0.555, P ? 0.01). Seed width also showed significant correlations with hard seed occurrence (r = -0.673, P ? 0.01) and imbibition rate (r = 0.613, P ? 0.01). At the same time, the obtained seed weight correlations were generally weak. The results also proved a seasonal difference in the hard seedness of blackgram, which confirmed the occurrence of hard seed during the summer compared to the Kharif season. Thus, the study's findings highlight the importance of seed morphometrics and imbibition in predicting the presence of hard seeds in blackgram.