Landslides pose a significant natural hazard requiring cost-effective, sustainable mitigation strategies. Nature-based solutions utilizing vetiver (Chrysopogon zizanioides) demonstrate considerable potential due to its deep, dense root system, which enhances soil reinforcement. This study examines the effects of growth medium composition and NPK fertilization on the root mechanical properties, biomass accumulation, and vegetative growth of vetiver under controlled greenhouse conditions. The planting medium comprised landslide-affected soil mixed with compost in varying proportions, combined with different NPK fertilizer levels. Root tensile strength was measured to assess mechanical performance, while biomass and vegetative parameters were evaluated to determine growth responses. Results indicate that both growth medium composition and fertilization significantly influence biomass production, root diameter, and tensile strength. The highest biomass (178.33 g) was recorded under T80P20N7.5, while the greatest root diameter (1.47 mm) and tensile strength (21.9 MPa) were observed under T100P0N0. These outcomes suggest a trade-off between biomass production and mechanical reinforcement. Overall, optimizing soil amendments and nutrient inputs enhances vetiver’s bio-reinforcement capacity, supporting its application in sustainable slope stabilization and landslide mitigation.