Autoflower Light Schedule

I’ve read a ton of comments about the light schedule for Autoflowers and I’m still a little confused! I’m looking for some clarity, do you need to flip from a 18/6 to a 12/12 light cycle? And if so what are the benefits of doing so? Or should I stay with the 18/6 for the whole life cycle?

I leave mine on 20/4 for the entire grow. 18/6 is fine to, I use to do it this way when I started. There is no reason to switch lights with autos. Only time you would “need” to switch, is if you were growing photo plants in the same tent…


With autos you don’t have to flip to 12/12 like you would photos, you can stay on 18/6 throughout the entire grow. If you want to save on your electricity bill you can run 12/12, but you will probably get better results running 18/6, unless your lights are high quality. If your growing photos with autos, then you would simply use the 12/12 once you switch photos to flower.


When i first started growing auto’s i I would keep them on 18/6 then switch them to 12/12/. Now I leave them on 18/6 for the hole grow unless i have a stubborn one that won’t flower.


I tried a SOG of northern lights autoflowers on a 6/2 light cycle. Eventually had to pull the plug when the plants grew too tall. They started flowering when they were about 12 inches tall but within a month had grown more then 5 feet tall and into the lights.

I tried the 6/2 light cycle to keep them from getting too cold during long dark cycles. Since then I have been vegging photoperiod plants under a 6/2 cycle with no issues.

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I agree with this. If a “breeder” releases duds, sometimes you’ll need to encourage them to flower. Another method that seems to help encourage early flowering is using smaller containers. 1 gallon pots or smaller seem to hold the plants closer to the schedules breeder’s advertise.


Thanks for the info!