Excessive use of conventional fertilizers in agricultural soils can lead to environmental contamination, particularly affecting aquifers and surface waters. Nanofertilizers, with smaller particles and greater nutrient efficiency, offer a promising alternative. This study evaluates the application of nanofertilizers by reducing NPK-doses compared to conventional fertilizers in the cultivation of Brassica oleracea L. convar. capitata var. sabauda (Savoy cabbage). Field assays were conducted in experimental plots with different NPK doses and treatments using urea-hydroxyapatite and potassium sulfate nanoparticles (optimum dose: 80 N, 100 P 2 O 5 , 250 K 2 O kg ha −1 ; and half optimum dosage). The assay was monitored throughout the crop cycle, and cabbages were harvested to determine biometric parameters, yield, and nutrient contents. The results indicated that nanofertilizers at half the recommended dosage yielded similar results to conventional fertilization in terms of cabbage growth and yield. Specifically, soil pH and available P increased by the end of the crop cycle, while total N, C, CEC, and soil texture remained unchanged, regardless of the fertilizer dose applied. Cabbage plants treated with nanofertilizers showed no significant differences in nutrient content compared to those treated with conventional fertilizers. This study supports the potential of nanofertilizers as an environmentally sustainable alternative that can reduce nutrient inputs in agriculture without compromising crop yield and quality.