To understand the effect of irradiance on flowering and the number of flowers, seedlings were grown under 30% shade (30% SH), natural irradiance(ND), and ND supplemented with 14 h of high irradiance at 14 W/m2(ND + 14HID) at 3 stages (ST) lastedfor 40 days (d) at each ST (Expt. 1).