Light Cycle Thoughts

Oldgrowth

Well-Known Member
Hey guys! What are your thoughts on veg light cycle lengths? 24 hours, 18hours or 16 hours?
My own observations are the 24 hour cycle can retard blooming if it used for extended periods, ie it takes longer for the plants to go into blooming once you turn to a 12/12 cycle. Havent noticed any difference between 16 and 18 hours.
Thanks in advance for your time!
 

DownOnWax

Well-Known Member
I have tried 24/0 and it does not seem to help the plants grow any faster.

I also keep mine on 18/6 to cut down on power costs and it is widely believed that plants use the night time to establish roots.
 

bigv1976

Well-Known Member
I have come to believe that the plants need sufficient dark time to grow a good root system. 18/6
 

gobbly

Well-Known Member
C3 plant. Most of the experts seem to agree on that, and that classification dictates no needed dark cycle. This has been written about by authors like mel frank and ed rosenthal, as well as many others. They pretty much all agree that increased light tine in veg will improve growth (including the root structure). My experience has also agreed with this. I have found many of the people who saw reduced growth on a 24/0 cycle were also having temperature issues...

Now to the OP, all of those sources also talk about the hormone responsible for inducing flowering, and I could easily see where this could cause a slightly longer time to switch to a flower cycle. But I doubt the difference would be any longer than a week, and it seems that the growth increase I have seen more than makes up for that time.
 

Oldgrowth

Well-Known Member
Thanks Gobbly I see we are on the same page here. I agree compleatly with you! Although i have seen as long as 5 week delayed blooming on plants veged for 24 for 6 months! Yes I think you right about the temps! Old Growth
 

Wetdog

Well-Known Member
I do a 18/6 cycle, but could see the 20/4 as a good compromise between that and the 24/0 cycle.

Everything needs some ZZZZZZZZZZZ's.

Wet
 
I use 24/0 when I start up and then switch to 18/6 once I have enough plants. For me, there is no question my plants grow faster under 24/0. The reason I switch to 18/6 is cost and slowing down the growth a little - my clones are in veg for 50-65 days before they move to flowering. The only difference I see is speed of growth, qualities like nodal spacing remain the same under both lighting regimes. In terms of flowering, can't see any difference - this seems to be driven by genetics and unaffected by the vegetative light cycle. Depending on the genetics, my plants consistently start flowering between 7-14 days regardless of 24/0 or 18/6. Cannabis does not require a dark cycle according to everything I've read and heard, my experience has been consistent with that.
 
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