Altered day length and flowering

What would a plant do with an altered day? With a controller we can make a day any length we want. 13 on 13 off, 14 on 12 off, 24 on 24 off. How do you think they would respond to longer days during flowering?

HIgh likelihood of hermaphrodite or re-veg. Not something I’d want to try.


@Kellogg i would not wanna go longer then 12 hrs of light unless using far red for emerson effect, even then, 13/11. Happy cannaversary @Myfriendis410


Photos or autos? How long a day do you want, as over 13 1/2 hrs triggers flowering in most photos. I’ve ran autos on 24/0. I’m just not seeing what your digging, what are you trying to do?

1 Like

It will reveg (and possiblly hermi) the plant if it is a photoperiod plant and you give the plant more than 12 hours of light per day. Autos don’t care and you can give them as much light as you want. You will want to stick with 12/12 with a photoperiod plant in flowering.

All that said, you can run a photo as many hours as you want if the plant is in veg and not flowering yet.


I remember @BobbyDigital and some others were using different light schedules like 6 on 2 off, never tried it myself. Is that enough manipulation?

1 Like

If they’re autos, light em up. If photos then @Myfriendis410 got ya.

1 Like

You are probably referring to the ‘Gas Lantern’ method which is for vegging plants.

I thought it was an interesting question that I wanted more knowledgeable feedback on. Or possibly feedback from someone that has tried an extended version of our 24 hour day and the effects on a flowering photo. Basically can a plant flower under 15 on 15 off or some variation of that.

1 Like

I think the trigger is the dark cycle. You could probably run an extended ‘day’ so long as you have a 12 hour ‘night’. But if you are running the correct DLI it shouldn’t be necessary.

1 Like

Over 13/1/2 hours of light and she’s no longer in flower and back in veg, so the answer is No.


As mentioned above photo will be triggered to flowers when growing under 12/12. These are moderne crosses and have been inter read for many years. Created to match the growers needs. Fast flowering, high in THC and also huge yields.

Look into true land race strains. These are strains that are native to there locations and have internal trails to allow them to thrive in those locations. Not the hybrids that we have today such as Bosscattie or Tropical Runtz but a true non crossed strain. Such as Colombian Gold or Hindu Kush.

Many of the location these plants originated from are close to the equator. Only fluctuating in day length by minutes in some locations. These strains where highly triggered by the intensity of the sun and the slight change in temperature.

So to really answer your question yes it is possible but due to years and years of inter-breading and crossing it is very rare with todays genetics.

Happy farming…