18/6 or 24/0 hour veg?

**billdubz785** · 12-22-2008, 01:57 PM

So I've searched the thread and maybe I don't know how to look but I haven't found anything telling me which light cycle is best.

The answer I've found was from the cannabis culture website. http://www.cannabisculture.com/articles/2291.html

Lamp Lighter,
New Brunswick, CT

THOUGHTS?

marijuana plantes photosynthesize as long as they receive light as well as water, air, nutrients and suitable temperature. Photosynthesis is the process in which plants use the energy from light (primarily in the blue and red spectrums) to combine carbon dioxide (CO2) from the air and water (H2O) to make sugar while releasing oxygen to the air.

Plants use sugars continuously to fuel metabolic processes (living) as well as for tissue building. The plant combines nitrogen (N) with the sugar to make amino acids, the building blocks of proteins. They are the substance of plant tissue. When the light is off, the plant's metabolic processes, respiration and growth, continue.

The plant can photosynthesize continuously so it produces the most energy and growth when the light is on, continuously. Continuous light does not stress the plant, which reacts somewhat mechanistically to it.

Plants under an 18-6 light-dark regimen are producing sugar only three quarters of the time. They are thus growing at only 75% of their potential. Leaving the light on continuously will result in bigger plants, faster, which leads to higher yields. By Ed Rosenthal

**xmegademonx** · 12-22-2008, 02:04 PM

from my experience, 18/6 had better plant growth. i tried 24/0 too, i dont know if this make sense, but the plants looked tired to me. they werent wilted or something but they were seemed to be asking for break lol. anyways, 18/6 had better growth than 24/0 in my experience.

**tasteskindasalty** · 12-22-2008, 02:11 PM

The case can be made for either, and until someone says, "hey, after repeated tests involving both cycles (and some control) I've determined [insert cycle] is better" I'm just going to stick to what I'm comfortable with. Honestly, for every article about how 18/6 is better I read another article about how 24/0 is better.

My personal preference remains 24/0 while in early seedling/veg development, 18/6 while in main veg development.

**billdubz785** · 12-22-2008, 02:20 PM

where do we find this someone, cuz I'm payin for the extra 6 hours

**Manowar** · 12-24-2008, 12:40 PM

Interesting, im new here and my first search led me here to find out which is better. Ed Rosenthal is supposedly a guru no? I may have to take his word and give 24 hours a try. I'm gonna continue looking on here though now. I actually started my seeds at 24hr and I thought it was too much for em so dropped back to 18. I've been waiting and wondering if/when to switch back.

**Papi Chingon** · 01-01-2009, 03:48 PM

i wonder if 24 causes more stress for seedlings, and then makes for a higher male ratio...

**carr0t** · 01-01-2009, 04:32 PM

i dont know what is right, but until i have the proper facilitys to conduct an experiment, i am going with 18/6 for main veg, i do like the idea of 24/0 when the plants are small and have little surface area, but i notice with my plants, that even near the end of an 18 hr day they seem tired by the end and begin to sag a little.. but in the morning after the lights have been on for 30 min they are firm and strong looking... i'd like to go 24/0 but i dont have the confidence or the willingness to screw up what i have going..

18/6 works great and is by far the most successfully proven number..... Not that there could be a better way but i know this works very well.

moving on, i was once reading that during flowering if u get the proper timer, you can set the lights to be on a 24on/12off, given that as long as the photoperiod(nightime) was greater than 10hrs the plant will fully flower. given that u can minpulate the light, u can theoretically get the same yeilds and quailty in about 7-10 days less time. Another experiment for my bright future.. no pun intended.

**bigjesse1922** · 01-01-2009, 04:34 PM

i use 20/4

gives them a break but couple extra hours. seems to be working well.

**snowmanexpress** · 01-01-2009, 04:53 PM

i thought i seen 18/6 was the weakest, but benefited your elec bill and possibly on a particular strain, maybe save on stressing the plant as well on this cycle I'd say....?

20/4 gave best results.

24/0 came in second place between 18/6 and 20/4 only due to yeild vs. electricity ratio I think.......where ratio of lights ON was a higher bill.

I swear I seen percentages as well between the cycles, of a growers journal with these light cycles, and what that person experienced and tabulated in percentages. Ill try to dig in my history for the link.

but hey its your plant, and my one and only lil lady so far, I did 24/0 cause I didnt have a timer early on in my grow, and my schedule is erratic at times, and I'm happy just to see growth due to my rookie inexperience.

**j420man** · 07-03-2010, 12:15 AM

i honestly believe that 24 is good as long as the room temp is under control if it is not, the plants are more likely to stress. under my 1000 its great but i have a medicinal pro room dehumidifier, air conditioner. exhaust fan on the light the works. so i can dial in any temp i want. if you are working underground for extra cash i would suggest 24 hr. floro veg with a 1000 for bloom in my experience 24 hrs. of floro will easily compete with 400 watt hid on 18/6 or pretty close. enough to think about. i use a 1000 mh 24 for veg at 78 degrees and they grow quick

if youre not making alot of cash off of what youre doing then i would go 18/6. but if you want them to veg faster because you grow for money then 24 if you can control room temp thats just my experience and input i'm a hydro grower also so i dont know if that makes a difference. hope this helps someone somewhere sometime piece