The global production of mineral fertilizers suffers from several critics due the serious problems, which penetrated the environment causing direct and indirect troubles for human health. Thus, the sustainable alternative “like bio-nanofertilizers" for the mineral fertilizers, that protects and conserves the environment will be a global aim. The present investigation introduces a simple and a fully-automated technique for producing bio-nano-fertilizers from abundant green materials. These nano-fertilizers were produced using plant extracts as a protocol for the biosynthesis of nanoparticles based-fertilizers. The innovative device can work automatically without human intervention by programming its units to produce homogeneous nanoparticles. Three plant extracts (i.e., Nerium oleander, Azadirachta indica, and Cinnamomum camphora) were selected to produce nano selenium using this device, and the nano-products were further investigated using both zeta potential and transmission electron microscope (TEM). Further investigations including more nano-fertilizers will be published in the future with more details for different kinds of nutrients.