Maize hybrid selection depends on several traits, including cob parameters. Hybrids respond differently to agronomic inputs, namely irrigation and fertilisation. Our study was conducted at Látókép Crop Production Experimental Site, University of Debrecen, Hungary, in 2023. The evaluation of the interaction effect of foliar fertilisation and precision drip irrigation on cob diameter, cob length, cob weight, and number of rows per cob in four maize hybrids (FAO390, FAO420, FAO430, FAO490) was performed under a randomised split-plot field experiment. Foliar fertiliser was applied at the 8^th leaf stage when the plant's leaves had fully developed with enough leaf surface area to absorb nutrients such as nitrogen (10 g/L), zinc (8 g/L), K₂O (8.5 g/L), P₂O₅ (0.83 g/L), and sulphur (8.93 g/L). Surface drip irrigation lines fixed at each row delivered 3 litres of water per hour, managed by the HydraWise app. Data were analysed by ANOVA using Genstat (18^th edition) software. Cob diameter and cob weight had significant differences (p < 0.01) between hybrids. FAO430 recorded the largest cob diameter (52.8 mm) and cob weight (31.5 g). Thus, the least performing hybrid, FAO420, exhibited a 10–15% difference, with a cob diameter of 47.9 mm and a cob weight of 23.7 g. Both cob length and number of rows per cob showed no significant differences (p > 0.05) among hybrids. FAO390 had a longer cob (19.7 cm) compared to FAO430 (18.4 cm). Irrigation had a significant effect on cob length (p < 0.001) and cob diameter (p < 0.05). Irrigated cobs had a 7.8% (cob length) and 2.1% (cob diameter) difference compared to non-irrigated cobs. Foliar fertilisation alone increased mean cob weight by 7% but no statistical significance across all traits. The interaction between foliar fertilisation and precision drip irrigation showed a positive effect on cob diameter (p < 0.001) and cob weight (p < 0.05) across all hybrids. Combined input application enhanced yield components compared to single-factor effects. Therefore, the interaction among hybrid type, precision drip irrigation, and foliar fertilisation has a profound effect on cob-related yield components.