Abstract <p>Optimal storage duration of polyethylene glycol (PEG) primed seeds is essential to ensure their viability and effectiveness, providing valuable insights to maximize yield potential and manage sowing times efficiently. The current study examined the effects of different storage durations (1, 5, 10, 15, 20, 25, and 30 days) on physiological and biochemical parameters of osmo-primed soybean seeds (PEG 6000 at –0.5, –1.0, –1.5, and –2.0 MPa), including control (non-primed) and hydroprimed seeds. The experiment was conducted twice under ambient conditions in a completely randomized design, with each treatment replicated four times. The results revealed that seeds could be effectively stored for up to 5 days with minimal quality loss, while longer storage durations led to a significant decline in germination percentage, seedling length and dry weight. Among the seed priming treatments, PEG at –1.5 MPa consistently performed better, demonstrating higher germination percentage, seedling vigour indices and dehydrogenase activity compared to other treatments. Additionally, seeds primed with PEG at –1.5 MPa exhibited lower electrical conductivity and higher percentage of 2,3,5-triphenyl tetrazolium chloride (TTC) stained seeds, reflecting better retention of seed quality. These findings suggest that PEG at –1.5 MPa is a viable priming treatment for maintaining the physiological and biochemical integrity of soybean seeds during short-term storage (up to 5 days), ensuring better germination and early seedling vigour even if sowing gets delayed due to unavoidable weather conditions.</p>