주요 사실

• Long-day plants flower when light exceeds a critical threshold (typically 14–16 h)
• Short-day plants flower when darkness exceeds a critical threshold (typically 12+ h of dark)
• Day-neutral plants flower regardless of photoperiod (e.g. cucumbers, tomatoes)
• Indoor growers use 18/6 (light/dark) for vegetative growth and 12/12 for flowering
• Even brief light interruptions during the dark period can delay or prevent flowering
• LEDs and timers give indoor growers precise, season-independent control