Abstract: The chrysanthemum (Chrysanthemum × morifolium Ramat.) is a typical short-day plant. In this study, the cut chrysanthemum ‘Reagan’ (Chrysanthemum × morifolium ‘Reagan’) was selected as material. We comprehensively analyzed the floral competence and the limited inductive photoperiod of seedlings. On these bases, the seedlings were treated under different combinations of red and blue light-emitting diode (LED) qualities, aiming at investigating the effects of different light qualities on the flowering of seedlings. The results showed that 1) the floral competence of seedlings was 14-leaf stage, and the value of limited inductive photoperiod was 43 d under short daylight (12 h light/12 h dark); 2) the blue light was necessary for the budding of seedlings, and the compound lights of blue∶red=2∶1 or red∶blue=2∶1 were more beneficial to the bloom compared with the single light (blue or red) and control group (fluorescent lamp); 3) the blue∶red=2∶1 was the optimal lighting option for the quick budding and bloom of seedlings under short-day light, the necessary time for bloom was only (86.19±1.17) d; and 4) the red∶blue=2∶1 was the optimal lighting option for the bloom under short-day light and the obtainment of high-stem plants (the plant height was (41.44±7.09) cm when budding). These results provide important references for annual production of cut chrysanthemum in a way of high efficiency and low energy, and also lay foundations for the protected cultivation of other ornamental plants.