Experiment was conducted to assess the “Effect of seed rate on yield, quality and water productivity of hydroponics fodder maize” at Bihar Agricultural University, Sabour, Bhagalpur, Bihar, India. The experiment was laid out in completely randomized design having five replication with six seed rate treatments viz., 500, 750, 1000, 1250, 1500 and 1750 g/tray. Seed rate with 1250 g/tray recorded significantly higher water productivity (0.49 kg/lit) as compared to 500 g/tray (0.36 kg/lit). The result revealed that, significantly highest green fodder yield (53.86 kg/tray) was observed with seed rate of 1250 g/tray as compared to 500 g/tray (35.50 kg/tray). However, significantly higher total dry matter accumulation and dry matter percentage was noticed with seed rate of 1250 g/tray (5.92 kg/tray) and (31.23 %) than that of 500 g/tray (3.55 kg/tray) and (23.53 %). Similarly, higher crude protein was noticed with 1250 g/tray (15.50 %) and lower at 500 g/tray (14.97 %) while higher nitrogen content was recorded at a seed rate of 1250 g/tray (2.48 %) and lower at 500 g/tray (2.40 %). The higher crude fiber and total ash recorded at 1250 g/tray (14.45 and 1.85 %) respectively. Among the different treatments, seed rate with 1250 g/tray has recorded higher net returns (Rs./unit 2,01243) and B:C ratio (3.86). Therefore, hydroponic fodder maize can be grown with seed rate 1250 g/tray produce higher green fodder yield with better nutritional quality.