The nitrogen concentration of AB mix fertilizer in the G2 fertigation system in the field would be influenced by various factors. This research aimed to increase the production of the G2 potato seed by using different concentrations of nitrogen in AB mix fertilizer in the fertigation system. The study was carried out in the G2 seed production area, Lembang, West Java, Indonesia from January to April 2019. The study used a randomized group design with four nitrogen concentrations in AB mix hydroponic fertilizer, namely 200, 215, 230, 245 ppm, and common AB mix (control) with five replications. The results showed that the number of big tubers of all nutrition formulas was higher than the control. The nitrogen concentration treatment increased the number of large tubers, small tubers, and total number of tubers, and decreased the weight per tuber compared to control. The best concentration to get the total number of tubers, small and large tuber, and weight per tuber was 217 ppm. The total number of tubers was affected by 93% by the number of small tubers. Meanwhile, the number of large tubers affected 78% of the tuber weight per plant.