Over the last 20,000 years, agriculture has become humankinds’ primary economic activity. Very recently (in comparison) nanotechnology has become a most promising area of scientific endeavour. This technology is creating exciting new opportunities in widespread areas of industry. These opportunities include in agriculture, where nanomaterials (NMs) offer improvements in nutrient supply efficiency to crop plants, that lead both to increased plant productivity and to increased sustainability in today’s sometimes quite unsustainable agroeconomic production systems. The role of NMs as nanofertilisers and as elicitors in plants has been demonstrated through numerous studies. The use of NMs can improve plant mineral composition and increase the synthesis and accumulation of numerous beneficial secondary metabolites. These secondary metabolites not only increase a plant’s tolerance of biotic and abiotic stresses of all sorts but also raises its nutraceutical quality and yield. There is a dearth of studies on the impacts of NMs used as nanofertilisers on traceability in the edible organs and on their long-term effects on soil health and water. This chapter offer a review of the effects of foliar, soil and substrate applications of NMs both as nanofertilisers and as elicitors on the mineral compositions and secondary metabolite compositions of food plants.