<p>Nutrients and water in a greenhouse should be supplied in appropriate amounts to support proper growth of the plants. Supplying nutrient solutions based on solar radiation can lead to over-application of nutrients relative to plant uptake, potentially causing nutrient imbalance or inefficient fertilizer use. Therefore, the study investigated the effects of reducing electrical conductivity (EC) of nutrient solution on the growth, fruit quality, and nutrient use efficiency (NUE) of cherry tomatoes in a smart farm system. Cherry tomatoes were cultivated under two irrigation treatments, with the decreased EC treatment maintained at 2.0-2.5 dS m^− 1 and the conventional EC treatment following conventional practices at 3.0-3.5 dS m^− 1. The plant-induced electrical signal (PIES), which reflects plant vitality and water uptake, was higher in the decreased EC treatment. The partial factor productivity (PFP), indicating fertilizer use efficiency, was approximately 38.7% higher in the decreased EC treatment compared to the conventional EC treatment. Plant growth parameters such as plant height, leaf length, fruit weight, and yield were also greater in the decreased EC treatment than in the conventional EC treatment. This is attributed to salt accumulation in the rhizosphere and osmotic stress in conventional EC treatment, negatively impacting nutrient uptake and plant growth. Principal component analysis (PCA) further confirmed that the decreased EC treatment was strongly associated with improved plant growth and fruit quality, whereas the conventional EC treatment was linked to higher nutrient concentrations in the medium. These findings emphasize the importance of managing nutrient supply based on rhizosphere EC to prevent salt stress and improve NUE.</p>