We proposed a new approach to enhance the germination of plant seeds via the electrospray of nanoparticles (NPs). A single-capillary electrospray system with a particle deposition stage (where seeds are placed) was set up for this investigation. For demonstration, lettuce (Lactuca sativa) seeds were bombarded by TiO2 NPs via the electrospray for 2–4 minutes in order to promote their germination. Based on our study, the enhancement in germination was significant in cases with aged seeds or seeds placed in an unfavorable growth condition (e.g., low pH medium). The electrospray of other NPs (i.e., Au) was also shown to be effective in enhancing the germination of aged lettuce seeds. TEM (Transmission Electron Microscopy) and SEM-EDX (Scanning Electron Microscopes and Energy-Dispersive X-ray Spectroscopy) analyses suggested that sprayed NPs could enter the seed coat via the frequent bombardment of NPs, thus breaking the coat-imposed seed dormancy. The enhancement of the germination of grass seeds was also observed in this study. The proposed seed treatment may have the potential to improve the germination of various recalcitrant crop seeds. Meanwhile, this study also indicates that nano-size aerosols may have a strong impact on plant physiologies.