24/0 vs 18/6

I am no expert but I ask all the experienced growers about veg light cycle it was always my understanding that there is more stem growth in the dark period, and 24/0 keeps the nodes closer together, are there any other benefits from starting off on a 24/0 cycle then moving to a 18/6.

Thanks in advance.

I think the idea behind an 18/6 or a 20/4 is that there is a point of diminished returns when going 24/0. I've always been under the impression that the dark period has more to do with saving energy than plant structure.

18/6 is the way i do things around here..

Been on this schedule for over 2 months now.

Been growing for 10 plus years using the 24 hour schedule.


Noticed much better roots on 18/6, and stronger/bigger stems.


I believe plants need rest to really move forward.. debateable subject I know.


I reccomend 18/6 over 24 hours.

i dont remember where but a couple days ago I read something where they did a test on different light cycles and 20/4 ended up being the best. i think 24/0 came second & 16/8 came in third

Thanks for the feedback guys, I was just going by my personal experience in gardening. I just always noticed there was always more spacing between nodes, when there was more of a dark period. I forgot about the 20/4 light period, that might be what i go with, everything so far has been under 24/0. I was just curious about this subject because now with a HPS running 24/7 the heat has ramped up a bit and thought introducing a dark cycle would drop it down a bit for a few hours a day.

i use 24/0 to offset the coldness when the light goes off on any other type of cycle.

are you growing from seed or clone? I like the tight node spacing of 20/4, but 18/6 will get you preflowers sooner so you can yank the males.

I go 18/6 and my nodes are tight. I also notice more growth from the lights off to lights on than i do from lights on to lights off.

WA.medigrow said:

are you growing from seed or clone? I like the tight node spacing of 20/4, but 18/6 will get you preflowers sooner so you can yank the males.

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Yeah I started from seed, if 18/6 shows pre-flowers faster thats def a plus, they are about 4-5 weeks in on some, and no signs yet of pre-flower. I was also condsidering growing 20/4 for a week then to 18/6. They have done well under 24/0 pictures below.

These are the 4 I just put under the HPS when i took the pictures.

can someone explain about the dark period or whatever its called between vegging and budding?

im doing 24/0 right now but i think i might start 18/6 my plants have been above ground for 3 days