The number of flowers and speed of flowering may not be evaluated properly only based on the irradiance without considering the greenhouse temperatures that may vary during the irradiance treatments. Therefore, 42 d of temperatures of 15/13.C (15.C),19/17.C (19.C), 23/21.C (23.C), and 27/25.C (27.C) and under ND + 10HD starting from on November 1 given to 45-d old plants.The number of days to visible buds and to flowering is accelerated mainly by temperature, and no further acceleration is observed above 23/21.C (23.C), regardless of the treatments prior to or following to formation of three pairs of leaves.