Nanotechnology introduces revolutionary approaches for agriculture in the form of nano-based pesticides, fertilizers, sensors, weed-controlling agents, enhanced seed germination materials, etc. Even though metal-nanoparticles (NPs) have shown their potential to improve crop yield, the mode of action at the cellular level and fate in the human body and the environment are not well understood yet. Several metal-nanoparticles have been studied extensively by researchers for their active role in enhancing the rate of seed germination and crop quality augmentation which may happen due to several mechanisms such as increased porosity in nano-primed seeds inducing up-regulation of the expression of aquaporin and Reactive Oxygen Species (ROS) genes involved in water uptake, improving the root dehydrogenase activity to enhance the water absorption capability, etc. However, researchers have also demonstrated and reported the possible toxicity of NPs in the environment due to their agricultural practices. But the fate of NPs and their environmental impact are still unclear and largely vary based on several factors such as the size of NPs, coating material, mode of discharge and locations, etc. This review thoroughly focuses on the mode of action of various NPs in seed germination and accumulation, translocation through cells, and potential environmental and health risks.