There is no doubt that many factors go into light schd. preferences, including but not limited to elct. costs, ambient/radiant heat strategies, feeding schedules etc...I always take great note in watching time lapsed photography of canna. The range of leaf motion both in growth and light/dark cycles is truly amazing. When I experimented with a 0/24 cycle many auto varieties exhibited fan leaf down "resting" periods during the 0/24. I wonder if it's variety dependent? Here is some info from a Dutch Passion White paper on the subject.12/12 light cycle for autoflowersA 12/12 light cycle is popular for blooming feminised cannabis strains. The lights are on for 12 hours and then off for 12 hours. Very often, growers may have spare space in their flowering tent and they can put this to good use by planting an autoflower seed or two. However, autoflowers will grow faster with better yields under 18, 20 or 24 hours of daily light than they will on a 12/12 light cycle.18/6 light cycle for autoflowersHow much light for autoflowers? What is the optimum autoflower seeds light cycle? These are two of the most common questions. The 18/6 autoflower light schedule is very common. It means 18 hours of daily light is followed by 6 hours of darkness. Many growers also use this light cycle for vegetative growth of their feminised cannabis seeds. An 18/6 autoflower cannabis light cycle tends to produce harvests around 10-11 weeks after germination.20/4 light cycle for autoflowersPerhaps the most common autoflower light schedule, and the one which Dutch Passion most often recommends is the 20/4 light schedule. This uses 20 hours of ‘lights on’ followed by 4 hours of darkness in each 24-hour time period. This light schedule delivers great results and seems to give the plants a healthy autoflower light cycle all the way from seed to harvest.24hr light cycle for autoflowersA 24 hour light for autoflowers is often popular during cooler winter months. In winter, grow room temperatures can often decrease faster than the grower would like during periods of darkness when the grow lights are switched off. One way to mitigate cold grow room temperatures is to grow autoflower seeds under 24 hour light. The grow light helps maintain grow room temperatures.It’s worth noting that not all auto growers recommend the 24 hour light cycle, feeling that an hour or two of darkness has certain benefits for auto plant development. But this view isn’t universally held.A 24 hour autoflower light cycle is also popular with those that grow their autos in the same room that they use for vegging feminised seedlings or keeping their mother plants. It’s also worth adding that those with particularly powerful lights and high PPFD levels may find that the DLI (daily light integral) is simply too much for some strains when the lights are on a 24 hour au