“…Other foliar applied nanoparticles as nanofertilizers include: iron oxide nanoparticles Fe3O4 NPs on Trigonella foenum-graecum and ginger plants (Siddiqui et al, 2015: Hao et al, 2018, silver nanoparticles (AgNPs) bean plants (El-Batal et al, 2016), silver and copper nanoparticles (AgNPs and CuNPs) on Scots pine and pedunculate oak (Aleksandrowicz-Trzci´nska et al, 2018: Aleksandrowicz-Trzci´nska et al, 2019, CeO2 NPs on soybean (Cao et al, 2017), titanium dioxide nanoparticles TiO2 NPs on Vetiveria zizanioides, Arabidopsis thaliana, Rice and Zea mays L. (Ze et al, 2011: Shabbir et al, 2019: Rizwan et al, 2019: Lian et al, 2020. Zinc oxide nanoparticles (ZnO NPs) on wheat, saffron, Sorghum, mung bean, and foxtail millet's (Raliya et al, 2016: Dimkpa et al, 2017: Hussain et al, 2018: Zhang et al, 2018: Kolenˇcík et al, 2019: Rostami et al, 2019 No literature detailed the synthesis of potassium nanoparticle using aqueous extract of Polyalthia longifolia leaf for over a decade, and none of the synthesized nanoparticle was foliar applied on Amaranthus viridis, Solanum lycopersicum and Hibiscus sabdariffa plants. This study aimed to biosynthesize potassium nanoparticles (K-NPs) and to determine its efficiency as a nanofertilizer on selected vegetables growth and development parameters such as plant height, stem diameter, root length, leaf length and plant weight.…”