This thesis explores the influence of Trichoderma strains (TR04 and TR05) and E. coli on the germination and seedling development of soybean and sunflower seeds. A series of in vitro experiments were conducted at 20 °C, tracking daily germination rates over a 7-day period and measuring seedling parameters (fresh weight, root length, shoot length). Microbial treatments were applied using a concentration of 10⁶ CFU/ml. Statistical analyses, including Shapiro–Wilk tests, Levene’s test, Welch’s t-tests, and Mann–Whitney U tests, revealed significant differences in germination outcomes between treatment groups. TR04 consistently inhibited germination in both plant species, while TR05 enhanced germination and growth in sunflower but inhibited soybean. E. coli and its combination with TR05 also reduced germination in soybean, especially after Day 4. The findings demonstrate that microbial effects on germination are highly dependent on both strain specificity and plant species. TR05 emerged as a potential enhancer of sunflower seedling vigor, showing promise for agricultural and microgreen production. However, caution is needed in soybean applications, as high microbial loads may disrupt seed development. These insights contribute to our understanding of plant-microbe interactions and open avenues for practical applications and further research.