When determining the appropriate amount of light for indoor cannabis grow rooms, PPFD (Photosynthetic Photon Flux Density) is a crucial metric, representing the average light on a surface. At the minimum, 800 PPFD is recommended, though some argue that increasing it to 1500 PPFD can improve yields. However, practical experience shows that 1500 PPFD is often excessive. An ideal range is between 1000 and 1200 PPFD. Growers exceeding 1200 PPFD typically encounter issues with burning or end up dimming their lights, while those operating at 800 PPFD or below generally experience significantly lower yields. Therefore, maintaining a PPFD of 1000 to 1200 is generally recommended.