Conventional strategies for soil fertilization are remarkably inefficient, as only a fraction of most  elements added with fertilizers are taken up by plants, the rest are typically trapped in the soil or leached to the aqueous environment, causing eutrophication. Thus, one of the most important current challenges of agriculture is to improve the sustainability of food  production via an improved fertilizer efficiency. In this project, we propose a visionary approach that bypasses nutrient fixation and microbial immobilization in the soil. We will produce the first generation of foliar fertilizers based on smart nanomaterials, tailored to effectively penetrate the micro- and nanoporous leaf cuticle. We will demonstrate that nanofertilizers can be tailored to trigger cellular internalization by endocytosis and subsequently be targeted to specific tissue and organelles where they are programmed to release their cargo of plant nutrients, right at the molecular targets where they enter metabolism. Small guiding peptides will be conjugated to target a range of different nanoparticles (NPs) scaffolds either composed of plant nutrients or encaging a cargo of nutrients. We will take advantage of the very diverse chemical environments found across different organelles and utilize differences in pH, redox and hydrolytic enzyme activities to program the organelle specific dissolution of the NPs. We will use a selection of plant nutrients as experimental cases, but the technologies developed will be flexible enough to allow the loading of NPs with practically any plant nutrient. We will keep a strong focus on the ecotoxicological effects of NPs, green chemistry approaches will be applied and only biocompatible substances will introduced into the ecosystems.