Background: Increasing demand for leguminous green manure crop daincha seed is being noticed throughout the country mainly to restore the soil fertility. For maximizing seed production of newly released daincha variety, an optimum plant density per unit area and fertilizer application are an important management tool. The study was conducted to optimize the plant spacing and fertilizer dose for achieving higher seed yield of daincha variety TRY 1. Methods: Field experiments were conducted during Summer and Kharif 2023 to study the effect of different spacing and fertilizer doses on growth, yield and economics of new daincha variety TRY1. The treatments consisted of five different spacing (S1-75×30 cm, S2-60×30 cm, S3-75×45cm, S4-60×45 cm and S5-90×30 cm) in main plots and three fertilizer levels (F1-12.5:25:12.5 kg N, P2O5, K2O ha-1, F2-18.75:37.5:18.75 kg N, P2O5, K2O ha-1, F3-25:50:25 kg N, P2O5, K2O ha-1 and control) in sub plots were tested. The treatments were replicated thrice in split plot design. Result: Growing of daincha variety TRY 1 at 60×45 cm spacing produced significantly taller plants (223 cm), more number of branches per plant (15.9) and dry matter production (1766 kg ha-1), yield parameters viz., higher mean number of pods per plant (114), pod length (22.4 cm) and seeds per pod (36.7), seed yield (567 kg ha-1), mean net returns (Rs.24512 ha-1) and benefit cost ratio (2.36) than other spacing. Application of 25:50:25 kg N, P2O5, K2O ha-1 recorded significantly mean taller plants (217 cm), more number of branches per plant (19.3), dry matter production (1831 kg ha-1), nodules/plant (40.7), more number of pods /plant (121), pod length (23.7 cm) and seeds per pod (37.8), seed yield (572 kg ha-1), net returns (Rs.23369 ha-1) and benefit cost ratio (2.20) over other fertilizer doses. Thus, the optimum spacing of 60×45 cm and fertilizer dose of 25: 50:25 kg N, P2O5, K2O ha-1 could be recommended for getting higher growth, yield parameters, seed yield, net returns and benefit cost ratio of newly released daincha variety TRY 1.