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 Themistopoloi
Registered: 02/15/09
Posts: 1
Last seen: 15 years, 10 months
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 doubts 
#196177 - 02/15/09 05:20 AM (15 years, 10 months ago) |
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it is true that on the night period if you need to go in the room a green light dont affect the cycle. and when flowering what matters is uninterupted 12 hour cycle can you run progresive lightning it means like 18-24 on followed by 12 off and so on.
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elaspeinreason
his serene highness
 
Registered: 04/21/08
Posts: 463
Loc: Washington DC
Last seen: 11 years, 9 months
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a green spectrum of light is still light and I believe that it would more than likely disrupt the plant.
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हम सब एक है ~ We Are All One
The ultimate source of happiness, successful life, is within ourselves. Do not dwell in the past, do not dream of the future, concentrate the mind on the present moment. - Buddha
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 Dr. Penguin
Registered: 05/19/08
Posts: 1,036
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I have seen green light used successfully during the flower cycle of mature plants without any negative effects. Try to use them as little as possible but if required, green light is relatively safe.
As for the second part, I have always heard that a non 24 hour cycle (20/12 on/off etc.) will positively affect yield. My professor on the other hand, has stated that a non 24 hour clock cycle will stress c3 plants (like cannabis) and reduce yield. I have never seen conclusive proof either way so maybe someone else can chime in.
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Dr. Penguin
Registered: 05/19/08
Posts: 1,036
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 This thread was moved from Hydroponic & Agroponics.
Reason:
Better off in general cultivation.
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Smoke
Cannibality
Registered: 02/12/09
Posts: 100
Last seen: 15 years, 10 months
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 Re: doubts (moved) [Re: Dr. Penguin]
#196322 - 02/15/09 07:01 PM (15 years, 10 months ago) |
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I am vagly interested in the hole lighting pattern that most use as well... so... whats the lighting secret... 
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]the technical name for using one's finger to extract boogers is rhinotillexis[/b
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BudZilla
Registered: 02/02/09
Posts: 37
Last seen: 15 years, 9 months
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Re: doubts (moved) [Re: Smoke]
#197080 - 02/17/09 11:57 PM (15 years, 10 months ago) |
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In the dark cycle the only light that you can bring into the room is blue LED light. Any other color spectrum (especially red light) will break the cycle. Blue light mimics the moonlight.
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Dr. Penguin
Registered: 05/19/08
Posts: 1,036
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Re: doubts (moved) [Re: BudZilla]
#197125 - 02/18/09 06:51 AM (15 years, 10 months ago) |
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Why blue LED light? I don't know if I would trust that. Check out this diagram for why:
Cartinoids generally are responsible for signaling dark length mediated photo-responses, as you can see in the chart, they stop absorbing around the green spectrum but would absorb any blue light you bring into the room.
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BudZilla
Registered: 02/02/09
Posts: 37
Last seen: 15 years, 9 months
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Re: doubts (moved) [Re: Dr. Penguin]
#197147 - 02/18/09 10:56 AM (15 years, 10 months ago) |
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I have used blue LED to check my room during dark cycle many times without breaking it. Cartinoids absorb red/orange light, which triggers the day cycle. I have read past science experiments where flashes of different spectrum light were introduced into photosensitive plants. Blue flashes do nothing, red flashes introduce day cycle, and far red flashes actually reset the night cycle.
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Yrat
Happy Planting
Registered: 04/20/08
Posts: 886
Last seen: 10 years, 10 months
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Re: doubts (moved) [Re: BudZilla]
#197154 - 02/18/09 11:28 AM (15 years, 10 months ago) |
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check out that top absorbance spectrum. carotenoids absorb in the blue end of the spectrum, reflecting red/orange light.
personally, i think that if you could get a green LED flashlight with a max of about 550nm, and a small bandwith, you shouldn't have to worry about anything. light of this wavelength is not used at all, and is completely reflected, hence why we see plants as green.
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 "Prohibition will work great injury to the cause of temperance. It is a species of intemperance within itself, for it goes beyond the bounds of reason in that it attempts to control a man's appetite by legislation, and makes a crime out of things that are not crimes. A Prohibition law strikes a blow at the very principles upon which our government was founded." - Abraham Lincoln
"There are a thousand hacking at the branches of evil
to one who is striking at the root"
~ Henry D. Thoreau
Strike The Root
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Yrat
Happy Planting
Registered: 04/20/08
Posts: 886
Last seen: 10 years, 10 months
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Re: doubts (moved) [Re: Yrat]
#197160 - 02/18/09 11:40 AM (15 years, 10 months ago) |
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after digging a little bit, i found that it is phytochrome that is responsible for detecting day length in plants. phytochrome absorbs in the red and far red, so blue light would indeed be ideal for working in a dark grow room. just make sure it's not a bright white LED, which can appear blue from such high intensity, but covers the entire spectrum.
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"Prohibition will work great injury to the cause of temperance. It is a species of intemperance within itself, for it goes beyond the bounds of reason in that it attempts to control a man's appetite by legislation, and makes a crime out of things that are not crimes. A Prohibition law strikes a blow at the very principles upon which our government was founded." - Abraham Lincoln
"There are a thousand hacking at the branches of evil
to one who is striking at the root"
~ Henry D. Thoreau
Strike The Root
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Dr. Penguin
Registered: 05/19/08
Posts: 1,036
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Re: doubts (moved) [Re: Yrat]
#197175 - 02/18/09 01:05 PM (15 years, 10 months ago) |
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It was believed that phytochrome was the only mechanism of photoperiodic response for a long time, it has just recently been discovered that cryptochrome plays a role as well. Cryptochrome absorbs light in the blue spectrum while phytochrome is predominantly red-orange. Here is a recent study that identifies the involved chemical pathways:
Quote:
* Regulation of Photoperiodic Flowering by Arabidopsis Photoreceptors
* Author(s):Todd Mockler, Hongyun Yang, XuHong Yu, Dhavan Parikh, Ying-chia Cheng, Sarah Dolan and Chentao Lin
* Source: Proceedings of the National Academy of Sciences of the United States of America, Vol. 100, No. 4 (Feb. 18, 2003), pp. 2140-2145
* Published by: National Academy of Sciences
* Stable URL: http://www.jstor.org/stable/3138498
Abstract
Photoperiodism is a day-length-dependent seasonal change of physiological or developmental activities that is widely found in plants and animals. Photoperiodic flowering in plants is regulated by photosensory receptors including the red/far-red light-receptor phytochromes and the blue/UV-A light-receptor cryptochromes. However, the molecular mechanisms underlying the specific roles of individual photoreceptors have remained poorly understood. Here, we report a study of the day-length-dependent response of cryptochrome 2 (cry2) and phytochrome A (phyA) and their role as day-length sensors in Arabidopsis. The protein abundance of cry2 and phyA showed a diurnal rhythm in plants grown in short-day but not in plants grown in long-day. The short-day-specific diurnal rhythm of cry2 is determined primarily by blue light-dependent cry2 turnover. Consistent with a proposition that cry2 and phyA are the major day-length sensors in Arabidopsis, we show that phyA mediates far-red light promotion of flowering with modes of action similar to that of cry2. Based on these results and a finding that the photoperiodic responsiveness of plants depends on light quality, a model is proposed to explain how individual phytochromes and cryptochromes work together to confer photoperiodic responsiveness in Arabidopsis.
Here also is a graph from a study done in the late forties involving floral repression at differing spectra:
The grey band indicates the blue area of the spectrum.
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Yrat
Happy Planting
Registered: 04/20/08
Posts: 886
Last seen: 10 years, 10 months
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Re: doubts (moved) [Re: Dr. Penguin]
#197192 - 02/18/09 02:00 PM (15 years, 10 months ago) |
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nice. so is green the winner?
--------------------
"Prohibition will work great injury to the cause of temperance. It is a species of intemperance within itself, for it goes beyond the bounds of reason in that it attempts to control a man's appetite by legislation, and makes a crime out of things that are not crimes. A Prohibition law strikes a blow at the very principles upon which our government was founded." - Abraham Lincoln
"There are a thousand hacking at the branches of evil
to one who is striking at the root"
~ Henry D. Thoreau
Strike The Root
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BudZilla
Registered: 02/02/09
Posts: 37
Last seen: 15 years, 9 months
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Re: doubts (moved) [Re: Dr. Penguin]
#197193 - 02/18/09 02:01 PM (15 years, 10 months ago) |
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All I can tell you is that for marijuana photosensitivity blue light will not affect it.
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Dr. Penguin
Registered: 05/19/08
Posts: 1,036
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Re: doubts (moved) [Re: Yrat]
#197201 - 02/18/09 02:51 PM (15 years, 10 months ago) |
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Quote:
Yrat said:
nice. so is green the winner?
Hahaha, I would say so. While budzilla is right, you could probably use blue light for very short periods of time and be fine; it would be even safer to use green light because enough energy in the blue range of the spectrum will interrupt the dark cycle.
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BudZilla
Registered: 02/02/09
Posts: 37
Last seen: 15 years, 9 months
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Re: doubts (moved) [Re: Dr. Penguin]
#197478 - 02/18/09 11:55 PM (15 years, 10 months ago) |
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No don't use green light, use blue. It doesn't matter how high energy the blue light is, it won't interrupt the cycle. Lab tests were done with very intense repeated flashes of blue light without problem.
Trust me guys, I have grown pounds and pounds and pounds of dank over many years and have learned from old hands of 20years+.
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Dr. Penguin
Registered: 05/19/08
Posts: 1,036
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Re: doubts (moved) [Re: BudZilla]
#197527 - 02/19/09 08:10 AM (15 years, 10 months ago) |
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Listen bud, you can use whichever color you please; but I will follow the advice of logical science and use green. I know you insist that this isn't a good idea, but can you prove it? Find the experiments you were talking about please, I searched last night and couldn't find them but maybe they exist somewhere.
I am totally ok with being proven wrong but without it, it's just hearsay.
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BudZilla
Registered: 02/02/09
Posts: 37
Last seen: 15 years, 9 months
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Re: doubts (moved) [Re: Dr. Penguin]
#197587 - 02/19/09 03:16 PM (15 years, 10 months ago) |
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Honestly, I have never used green light in my grow rooms during dark cycle so I could not say whether or not it is safe, its just that I know for 100% sure that blue light is safe.
My info on blue and red flashes comes from my college botany book (The Biology of Plants, 6th edition, Freeman Worth publishing)
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Dr. Penguin
Registered: 05/19/08
Posts: 1,036
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Re: doubts (moved) [Re: BudZilla]
#197591 - 02/19/09 03:31 PM (15 years, 10 months ago) |
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Ha! Thats hilarious, first place I looked was that book. I have it sitting in front of me (I lied, it's 7th edition). My copy is way outdated though. The experiments I'm talking about are less than 10 years old so they would not have made their way into the text yet.
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BudZilla
Registered: 02/02/09
Posts: 37
Last seen: 15 years, 9 months
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Re: doubts (moved) [Re: Dr. Penguin]
#197593 - 02/19/09 03:42 PM (15 years, 10 months ago) |
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You take a college level botany course like me Dr. Penguin? It was probably the hardest class I ever signed up for.
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Dr. Penguin
Registered: 05/19/08
Posts: 1,036
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Re: doubts (moved) [Re: BudZilla]
#197622 - 02/19/09 06:40 PM (15 years, 10 months ago) |
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Actually I'm a plant science major here at university. Definitely tough stuff but I enjoy it.
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