The objective of this study was to optimize the culture medium for enhanced production of Bacillus velezensis AP-3 endospores using both liquid and solid-state fermentation techniques. Additionally, the study aimed to assess the stability of endospores in powder formulations containing talc and potato starch, and to evaluate the growth-promoting effects of these formulations on bean plants. Further, we evaluated the inhibition of mycelial growth of Sclerotinia sclerotiorum and Fusarium oxysporum f. sp. lycopercisi by metabolites produced by this bacterial strain. The plant growth promotion assay evaluated these formulations across various application methods: seed treatment, sowing furrow application, and a combination of both. Adjustments to culture medium significantly influenced the endospore yield of B. velezensis. Solid-state fermentation in rice flour and potato starch yielded up to 2.06 × 10