Chemical fertilizers boost yields by ~50% but reduce plant–microbe interactions, harming soil health. Plant growth-promoting microorganisms (PGPMs) offer a sustainable alternative by enhancing nutrient uptake and growth. In a greenhouse study using a randomized block design (10 treatments, six replicates, two fertilization levels), maize inoculated with rhizospheric strains showed improved nutrition. H. seropedicae and G. diazotrophicus increased nitrogen, while B. pumilus and B. amyloliquefaciens improved phosphorus uptake. Fertilized plants had higher shoot dry matter, but microbial inoculation reduced dependence on fertilizers. Strains tested included G. diazotrophicus, H. seropedicae, A. brasilense, B. amyloliquefaciens, B. subtilis, and B. pumilus (16S rRNA ID: MT604067). Statistical analyses (Duncan, Shapiro–Wilk) confirmed significant treatment effects, highlighting PGPM potential for sustainable maize production.