Tomato (Solanum lycopersicum L.) is a highly esteemed horticultural crop that is consumed in various forms, including raw and processed. Contemporary agriculture employs both conventional and organic fertilizers to enhance crop yield and optimize efficiency. Conventional fertilizers have been shown to enhance agricultural productivity, but their usage has been linked to negative environmental consequences. Those circumstances provide motivation for the exploration of an alternative resolution.

The purpose of this study was to investigate the effects of nano-ZnO (at conc. 50, 150 and 250 mg/L) administered in two distinct ways (foliar spraying and directly into the soil) along with conventional fertilizer on tomatoes. After cultivation, the plant tissues, including aboveground parts of the plants and fruits were analyzed in detail. The findings indicate that the utilization of nano-ZnO in tomato plants had an impact on the plant's biometric parameters and its antioxidant capacity. The outcomes of the performed analyses were dependent upon the concentrations of nano-ZnO utilized or the method of their administration. Further investigations revealed that the utilization of nano ZnO resulted in an elevation of malondialdehyde (MDA) levels and other chosen antioxidants’ activities in the aerial parts of the plant. On the other hand, the utilization of nano-ZnO resulted in a slight reduction in the levels of chlorophyll and carotenoid in the chosen plants, along with a decrease in the quantity and mass of the harvested fruits. However, a reduction in fruit weight aside, the application of nano-ZnO resulted in an elevation of lycopene and β-carotene levels in the fruit of chosen plants.