View Full Version : Blue light after 'dark'?
RackitMan
05-16-2009, 05:14 PM
Has anyone here tried using pure blue light (LED or actinic fluoro) during the 'dark' or night phase when in 12/12 light cycle to keep photosynthesis going without interrrupting the flowering phase?
I have one of the newer 50 watt blue LED panels and may give it a try, but would like to get some feedback first.
the image reaper
05-16-2009, 10:46 PM
Edit: sorry, I started to answer your question, but am now aware, that I don't understand what you're trying to do, with the blue light :wtf: :D
oldmac
05-16-2009, 11:14 PM
Has anyone here tried using pure blue light (LED or actinic fluoro) during the 'dark' or night phase when in 12/12 light cycle to keep photosynthesis going without interrrupting the flowering phase?
I have one of the newer 50 watt blue LED panels and may give it a try, but would like to get some feedback first.
Hi there RackitMan,
I'm also not sure what you hope to gain by that. I use a super actinic white in my cloner light set up and sometimes used to start germed seeds. Use only the actinic till roots show or seedling emerges and then add 6500k fluoro. Ususually keep actinc white going also.
I know of some people who are using blue LED panels for clonning, but not used during dark period.
Some here are curious, I know I'm curious, tell us more please.........
couple of pics of actinic in action
BeFree
05-16-2009, 11:19 PM
http://boards.cannabis.com/grow-log/165934-first-attempt-24-hour-martian-method.html
I've heard of far reds at night and whatnot. I dunno what to tell ya bud.
beSafe:jointsmile:
RackitMan
05-16-2009, 11:47 PM
Hi there RackitMan,
I know of some people who are using blue LED panels for clonning, but not used during dark period.
Some here are curious, I know I'm curious, tell us more please.........
To the best of my knowledge, 12/12 red light signals the plant to flower whereas blue light does not trip flowering on or off. Therefore, using pure blue during the normal 12 hour 'off' period should allow photosynthesis to continue without disturbing the flower cycle. This should allow for greater/faster growth if my hypothesis is correct.
As I only have time/space for 2 mini grows per year it is difficult for me to test at this time.
oldmac
05-17-2009, 09:06 PM
To the best of my knowledge, 12/12 red light signals the plant to flower whereas blue light does not trip flowering on or off. Therefore, using pure blue during the normal 12 hour 'off' period should allow photosynthesis to continue without disturbing the flower cycle. This should allow for greater/faster growth if my hypothesis is correct.
As I only have time/space for 2 mini grows per year it is difficult for me to test at this time.
OK Rackit,
First, since you are doing just a couple of grows a year in limited space, you need to stick to tried and true methods to grow. It's the best way to get good and consistent results. I would assume if one of your two grows went tits up it might be a lousy year.
Second, just recently I kinda tested that theory (without knowing it) and the results were unwanted hermies. I built a couple of rooms on the quick and cheap and used 1" thick Dow "blue board" stryfoam insulation to make the walls. Realized it was not light tight, but in the bloom room with lights out, there was no light bleed thru two layers of foam with a cloner light set-up going. Unfortunately I did not check it again after I started using a 600w MH, about a month later I was checking the bloom room for the sequencing of the lights and light fan going off. After everything went dark and my eyes adjusted, I saw this large blue sunrise thru the wall, I could even see where the wood wall studs were. Next day covered the offending mom room with white poster board to solve the problem.
The result of this "blue glow" for abt 3-4 weeks was hermies. Not a fun way to start a grow.
Just based on this experience, I don't think it would work, unless you consider growing seeds "greater" growth.
the image reaper
05-18-2009, 02:30 PM
I'm still foggy on the reasoning behind this, so be patient with me :D ... if you're just trying to delay flowering, just leave the plant under 18 hours of light ... I gotta be missing something here :wtf: ... but, unless you're growing sativas, you should have plenty of time, to grow out two gardens a year ... that's a piece of cake ... in fact, with 50-day varieties, three harvests is easy ... regardless, good luck, sorry I couldn't help :smokin:
Italiano715
05-18-2009, 03:47 PM
Basically, he/she would be growing in 24 hours lighting if you have a blue light off at dark.....I seem to be missing the point also. :wtf:
RackitMan
05-18-2009, 08:10 PM
Basically, he/she would be growing in 24 hours lighting if you have a blue light off at dark.....I seem to be missing the point also. :wtf:
Forget my personal grows, guys - that is not relevant.
What is not to understand? 24 hours of growth > 12 hours of growth. This is pretty basic.
headshake
05-18-2009, 08:40 PM
from what i understand, the blue spectrum of light is only responsible for certain things in photosynthesis. in part for chlorophyll a, chlorphyll b and phycoerythrin and (almost) all of the carotenoids. and the very beginning of phycocyanin.
so i'm not sure if the blue light running 24 hours would be of benefit. i have no scientific proof of this, it's just a hypothesis.
-shake
metalhead419
05-18-2009, 08:56 PM
not to sure on this one but i will take a guess and say, no. There wont be any benefit. Plants depend on both red and blue light to photosynthesize properly, and blue is mostly just for internode length. Probably would make your plant hermie or maybe just make it do some crazy shit none of us have ever seen. Just my opinion. Im sure i could ramble on a little more, but i dont think i would be telling you anything you dont know, lol. Try it, and let us know, definitely an interesting experiment.
DreadedHermie
05-20-2009, 08:51 AM
16 hours of blue(ish) light, and upwards, is generally called a "veg room." :D . . . . . The idea, of course, is "not" to get flowers.
pure blue light (LED or actinic fluoro)
Blue led vs. Actinic fluoro is apples to oranges. Well, maybe kumquats to oranges. :D Compare the spectral graphs. LED = scalpel. Fluoro = shotgun.
And in this dirty world, nothing is "pure". :(
To the best of my knowledge, 12/12 red light signals the plant to flower whereas blue light does not trip flowering on or off.
Do you recall where you got this information? I'd double check it. 12 / 12 @ 6500K (some actinics are not so far from this) will induce flowering quite effectively; I've done it.
If you're got spare harvest to experiment, try it and let us know. But if you're growing needed medicine (lots of people on this site are, that's why I butted in here, sorry...) or for other reasons can't afford to mess up your grow, I'd research this a bit further before risking your success. Either way, good luck! :thumbsup:
the image reaper
05-20-2009, 04:12 PM
correct, the flowering onset is triggered by the hours of light, the red spectrum just helps flowering, by imitating how the Fall sun's wavelength changes as it lowers on the horizon ... I vegged and flowered for years with only blue lights (not knowing, red would have been better) ... but, why you would want blue light during flowering (after you know red is more effective, is beyond me) ... either way, best of luck to ya :smokin:
RackitMan
07-23-2009, 07:43 PM
At least newbie Ed Rosenthal understood and now recommends 24 hours of blue LED throughout the entire grow cycle.
I am amazed at the close-mindedness and lack of understanding of cannabis photoperiods or real attempt to understand something new.
the image reaper
07-23-2009, 09:46 PM
piss on Ed Rosenthal, he's a clown :wtf: ... his fame came as a result of his partnership with Mel Frank, the 'botany brains behind their books' ... regardless, sounds like you know more than us closed-minded folks, anyway ... happy growing ... :D
oldmac
07-25-2009, 01:27 PM
At least newbie Ed Rosenthal understood and now recommends 24 hours of blue LED throughout the entire grow cycle.
I am amazed at the close-mindedness and lack of understanding of cannabis photoperiods or real attempt to understand something new.
Hey RackitMan, could you please supply me with a reference to where Ed Rosenthal now recommends 24hr blue LED throughout the entine grow cycle?
I started searching and have been unable to find this, I really would like to read it all in context to better understand what he is saying and any reasoning behind it.
As to understanding of photoperiods, let me show you by correcting IR's statement (and other's belief) that "flowering onset is triggered by the hours of light...". This is wrong, the amount of light or duration of photoperiod has no effect on flowering. It is the amount of dark period that determines when a plant flowers and if it stays in flower. During the dark period certian hormones (and enzymes) increase in the plant, when they reach a certian level they act like a switch to trigger the plant to go into the "sexually mature" stage (flowering). Aprox 8hrs or less of dark means the plant will stay in the "immature" stage or vegative phase, aprox 10 or more hours of dark and flowering will occur. BTW; the hours of dark to get a plant to trigger and hours of dark needed to keep it in flower can be different.
I try to learn something new everyday, and am always open to new ideas...hell I've been experimenting and using LED technology for over 2 years, in spite of hearing "led's don't work" from people the entire time. Share some additional info, inquiring minds want to know!
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