Day-extension blue light inhibits chrysanthemum flowering when far-red light is included: Study

Most ornamental crops can be classified as long-day, short-day, or day-neutral plants based on their flowering responses to the photoperiod (which is the day length), or the skotoperiod (which is the night length). Chrysanthemum is a common ornamental crop with an obligate short-day flowering response and only flowers when the night length is consistently longer than a critical duration.