Oilseeds play a crucial role in the national economy. To enhance their productivity, innovative approaches such as nano fertilizers are essential in the present-day context. The environmentally friendly synthesis approach was employed to produce stabilized nano sulphur using Simarouba glauca leaf extractant. The characterization of the nanoparticles involved identifying functional groups through various analytical techniques, including Raman spectroscopy and UV-visible spectroscopy, as well as examining the electronic properties of sulphur nanoparticles. Structural analysis of the sulphur nanoparticles revealed an orthorhombic configuration through Powder X-ray diffraction tests. In-depth examinations using scanning electron microscopy and transmission electron microscopy showcased particle sizes below 100 nm. In a laboratory experiment, sunflower seeds treated with 600 ppm green-synthesized nano sulphur demonstrated remarkable root morphology and achieved the highest root growth parameters, surpassing other concentration levels and control treatment. Importantly, the environmentally friendly synthesized nanoparticles exhibited longer stability and greater efficacy when compared to both chemically synthesized nanoparticles and conventional fertilizers.