All dahlia ‘Leanne’ plants flowered under all NI lightening treatments, but flowering percentage under SDs was 100% and 20% in the first and second replications, respectively (data not shown). Com-pared with SDs, all NI lighting treatments except B NI delayed appearance by 6–12 d and flowering by 7–13 d (Table 3). ‘Leanne’plants grown under B + R and B + FR NI flowered 5 and 6 d later,respectively, than those grown under B + R + FR NI. At flowering,plants were tallest under treatments emitting FR light (i.e., INC,B + FR, B + R + FR, and R + FR NI), and those under B NI and SDs were shortest. Plants grown under all NI lighting treatments except B NIhad approximately two more VBs than those grown under SDs. The Increase in leaf number of ‘Leanne’ at flowering showed a treatment response similar to that of flowering time, developing the most and fewest leaves under B + FR NI and SDs, respectively.