Seed biopriming induces a physiological condition that promotes germination and uniform seedling emergence. An investigation is carried out on different seeds such as carrot (Daucus carota subsp. Sativus), onion (Allium cepa L.), cauliflower (Brassica oleracea), radish, (Raphanus sativus), tomato (Solanum lycopersicum), spinach (Spinacia oleracea), fenugreek (Trigonella foenum-graecum), and pea (Pisum sativum) to standardise bio-priming with Bacillus siamensis strain NKIT-9 to improve seed germination and seedling vigor index. To optimise the concentration of bio-priming seedlings were bioprimed overnight with Bacillus siamensis strain (NKIT-9) at varied concentrations (0.1mg/ml, 10µg/ml, 0.1µg/ml, and 10ng/ml). Bio-priming with Bacillus siamensis strain NKIT-9 gave highest values of germination percentage and seedling vigor index of carrot (at 0.1mg/ml), onion (at 0.1µg/ml ), cauliflower at 0.1mg/ml, 10µg/ml, and 0.1µg/ml), radish (at0.1mg/ml and 0.1µg/ml), tomato (at 0.1mg/ml), spinach (at 10ng/ml ), fenugreek (at 10ng/ml) and pea (a10ng/ml ) as compared with control. carrot, onion, cauliflower, radish, tomato, spinach, fenugreek, and pea exhibited higher germination percentages (60%, 100%, 100%, 100%, 80%, 90%, 100%, and 60% respectively) and seedling vigor indexes (148 ,720, 910, 880, 525, 580, 990, and 1018 respectively) when compared with control. Therefore, bio-priming with these concentrations is best suited for improving germination rate and seedling vigor of seeds.