Would This Make a Difference in Yield?

A customer has a question and I hope we can get some opinions on it, thanks.

“I run my lights 24/7 until time to force flowering. It usually takes a week to begin flowering. After 2 to 3 weeks of having the lights on 12/12 I put the lights back to 24/7 again. I’m curious whether I would get better flowers if I left the lights at 12/12 or if it would only slow the growth. I always put them back to 24/7 after the flowering begins but I’ve never tried leaving them at 12/12 for the remainder of the flowering period. Just curious if it would make a difference in yield.”

If they are photo period plants, changing lights back would probably force them back into veg stage. Thus lessening your yield if you do not go full 12/12 throughout flowering. I have little experience with photo plants, but all I have read says they revert back to veg stage (this is how a lot of people tell the sex of their plants before continuing their grow)

If they are Autos, it does not matter a whole lot, as they will do their thing regardless…


I also believe you are taking a large chance at stressing a photo-period plant out by reverting back to 24/7. It can put it back into veg (like Ron said) or make it hermaphrodite. I am assuming it is not auto flower because u had to put it in 12/12… I recently have been messing with light timing myself. I turned my plants to 12/12 and about 2 weeks in changed it to 13.5 on / 10.5 off… I seen signs of stress after a week and decided it was to large of a chance to take. They are now back on a 12/12 schedule. I am debating switching to 12.5 on for the last week… I am making the assumption that more light can produce more yield if it doesn’t stress them out to much. Good luck and give those girls some dark!!


It’s the coming of the fall and the shorter days that trigger the flowering response in the plant. You are in essence making the plant thinking summer is following autumn. The buds will begin to shrink and all your sugar leaves will begin to stretch and grow into branches, this will negatively affect your yield and in a drastic way if you never return it to flower.

Don’t make this mistake while your plants are flowering brother…

Some people swap lights up in the flowering period but they cycle to longer periods of dark. If you revert a plant back to veg because of messing up his light schedule it doesn’t mean that he will immediately revert back to flower when the 12/12 scheduling is restored. This is why people freak out if the plant just gets a quick burst of light during flowering dark period, that plant might revert itself to veg and not return to flower for some time, even with 12/12 running

All plants need a rest period
Your doing more harm then good with 24-7 lighting
Things happen when lights are out that promote healthy growth tou should switch to a 18-6 min
I actually run 16-8 in my grow room for veg :+1:


My plants are on a 12/12 light schedule now. @TDubWilly I have read that some strains can handle more hrs of light then others and will bulk up more because of it. I am not talking anything excessive like 24/7 but a extra 1/2 hr to 1 1/2 hrs. My strain didn’t revert to Veg. but it did show signs of stress with a extra 1 1/2 hrs. So I immediately put it back in 12/12. I am considering a extra 1/2 hr for the last week of flower. I may decide against it when it comes time.But I am considering it. Correct me if I am wrong but people worry about shots of light in the middle of dark periods with super sensitive strains that will Hermie easily because of it. I think it takes a lil bit of time to revert a plant back to veg. I personally would not put a photo-period plant into 24/7 light cycle once in flowering.

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You nees 12-12 for flowering and any more will cause them to revert back but that takes weeks to happen fully the stress was them starting to revert back @WheresDaveMan

I run 20-4 light schedule for veg… @Countryboyjvd1971 . We were talking about a customer who switched back to 24/7 after plants were put into flower. I did not do that.

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10-4 @WheresDaveMan i wouldnt personally even run that tho in my grow room but if it’s working for you :+1:

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It seems like I read this somewhere along the way also, don’t remember what the source was or exactly what it said but I wouldn’t experiment with this on a plant I considered my baby.


Right on @Countryboyjvd1971… To each their own. I have had very good luck with my plants on a 20 on / 4 off light cycle for veg. I am happy with my yield and the health of my plants. I mean at some point I might try a different light cycle for veg just to save a few bucks on electric. I always consider my options.

Taken Today a lil over 3 Weeks into Flower:


Out of like brother but they definitely look nice
Exactly to each there own :+1:
More than one way to skin a cat and all that hahha
I personally try to stay closer to natural light patterns
Myself but as i stated if it working for you cool bro


I’m on a 16/8 schedule and the plants are ridiculous. Healthier than 24/0 IMO.

If you want to run long hours, grow autos, and if you want more light, add more light haha!

I use the same schedule @Myfriendis410 and couldn’t agree more
Tryed 14-10 and plants stared to flower as soon as they where mature enough but 16-8 seem about perfect fir my grow room plants grow faster than when i used 18-6 as well
Alot happens in a olant when light go out
And if people understood the plants they would realize this :+1: