how does a plant know that it is dark?

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ricardezra

Member
people say that light does not matter to flowering.well how does it know that it is dark?if you use a greenlight during flower it wont hurt the flower period.thats light? you can use a blacklight during lights out too it will not hurt the flower.thats light too? you can do 16/8 during veg and use a blacklight on lights off they stay veg.switch to 12/12 then on the lights out use a blacklight. is this not 24 hours off light the entire grow.it must be the red spectrum that the plant loose when you switch from 16/8 to 12/12
 
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ricardezra

Member
i saw somewhere, im still searching, that red spectrum is the key to marijuana knowing that it is dark. of course red has other functions too but one of them is to tell time.blue light has many functions too but one is photosynthesis.well logic says to me"well if this is true lets use a 400 watt hps 16/8 for veg,and on the dark cycle lets put a light with a all blue spectrum(blacklight) the plant will still think its dark and photosynthesis at the same time. heck it will will still feed itself and burn carbs and grow faster and never rest sense it thinks its dark" well to me that makes alot of sense then switch to 12/12 when the plants mature. and use your 400 hps during lights on. and on lights off use the blacklight ,your buds will still grow and photosynthesis and plant will still do what it does at night cuz it still thinks its dark. i hope that clears up my theory to all who has seen my other post. I have done this three times with regular seeds and no hermies in fact my bud was so thick and sticky and tight I was like wow just wanted too share this info but as i find there is a lot of people WHO THINK THE WORLD IS FLAT AND ARE NOT OPEN TO NEW IDEAS. im not saying that lost light makes plants start to hormone its tru lost off light makes plants flower BUT YOU HAVE TO ASK YOUR SELF HOW DOES IT KNOW ITS DARK?
 
homebrewer

homebrewer

Well-Known Member
ricardezra said:
yea but witch light spectrum is it?
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http://www.bcb.uwc.ac.za/ecotree/photosynthesis/spectrum.htm

Chlorophyll does not absorb all the wavelengths of visible light equally. Chlorophyll a, the most important light-absorbing pigment in plants, does not absorb light in the green part of the spectrum. Light in this range of wavelengths is reflected. This is the reason why chlorophyll is green and also why plants (which contain a lot of chlorophyll) are also green. Note in the graph above that the absorption of light by chlorophyll a is at a maximum at two points on the graph 430 and 662 nm. The rate of photosynthesis at the different wavelengths of visible light also show two peaks which roughly correspond to the absorption peaks of chlorophyll a. Plants do not depend only on chlorophyll a in their light harvesting machinery but also have other pigments (accessory pigments) which absorb light of different wavelengths.
 
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ricardezra

Member
homebrewer said:

http://www.bcb.uwc.ac.za/ecotree/photosynthesis/spectrum.htm

Chlorophyll does not absorb all the wavelengths of visible light equally. Chlorophyll a, the most important light-absorbing pigment in plants, does not absorb light in the green part of the spectrum. Light in this range of wavelengths is reflected. This is the reason why chlorophyll is green and also why plants (which contain a lot of chlorophyll) are also green. Note in the graph above that the absorption of light by chlorophyll a is at a maximum at two points on the graph 430 and 662 nm. The rate of photosynthesis at the different wavelengths of visible light also show two peaks which roughly correspond to the absorption peaks of chlorophyll a. Plants do not depend only on chlorophyll a in their light harvesting machinery but also have other pigments (accessory pigments) which absorb light of different wavelengths.
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that does not tell me anything i know that but you can grow a plant with just blue light. im not saying do this but you can.the plant will veg. it does not need full spectrum light to grow right?but cut the light to 12/12 they still dont flower why? its dark the now its dark why they dont flower?
 
Alarm Clock

Alarm Clock

Well-Known Member
You can flower under only blue light. It's not preferred, as it's generally agreed that the red end of the spectrum produces fatter buds while the blue end is better for leafy, vegetative growth. If you are saying you can't get a plant to mature to flower by using only blue lights, you are wrong.

...i know that but you can grow a plant with just blue light. im not saying do this but you can.the plant will veg. it does not need full spectrum light to grow right?but cut the light to 12/12 they still dont flower why? its dark the now its dark why they dont flower?
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Try to find some metal halide only grows.

At least homebrewer tried to support part of what you were saying. Sorry you missed it.
 
freddiemoney

freddiemoney

Well-Known Member
ricardezra said:
yea but witch light spectrum is it?
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You started a new thread looking for things you wanted to hear and ended up getting the same answers and criticisms you found elsewhere.

The plant will use whichever blue/red spectrum it can get and use it the best it can for photosynthesis. It wants to survive no matter how people abuse it. You could veg with an HPS and flower with a MH just fine, but the reverse has become the standard as it tries to copy the change in spectrum over the outdoor growing season and produces better results.

At night there is no secret spectrum that is left over. You can't have any light spectrum without any light.

What has convinced you that a plant won't flower if you only have a blue spectrum light?

I think that the rest of us think that the world is round while you're the one trying to tell us all that its a triangle.
 
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gobbly

Well-Known Member
I don't think he's saying it won't flower under only blue. The way I have understood his argument is that if you could get a light that only emitted light in shorter wavelengths than ~620nm (basically cut out all the red spectrum), and left it on your plant 24/7, the plant would in fact think it's dark all the time, and as such would enter a flowering phase. So basically he is saying that as far as night cycle regulating, red is the only color of light which the plant 'sees as light'. You can take a look yourself at the origins of his question at https://www.rollitup.org/advanced-marijuana-cultivation/354520-green-light-spectrum.html.

For the record, I don't agree with him. It's possible the black light just isn't putting out enough energy to interrupt flowering, at least in usable bands, it started to flower and is committed to finishing, or there is some auto-flower genes in there that he's not aware of. His extrapolating his experience with the black light to saying that only red light regulates flowering seems very unfounded. Just from the way he talks I can guarantee I have done way more research on the topic of light spectrum and photosynthesis, and have yet to see him give one shred of scientific evidence, or a source, which corroborates what he is claiming.
 
freddiemoney

freddiemoney

Well-Known Member
gobbly said:
I don't think he's saying it won't flower under only blue. The way I have understood his argument is that if you could get a light that only emitted light in shorter wavelengths than ~620nm (basically cut out all the red spectrum), and left it on your plant 24/7, the plant would in fact think it's dark all the time, and as such would enter a flowering phase. So basically he is saying that as far as night cycle regulating, red is the only color of light which the plant 'sees as light'. You can take a look yourself at the origins of his question at https://www.rollitup.org/advanced-marijuana-cultivation/354520-green-light-spectrum.html.

For the record, I don't agree with him. It's possible the black light just isn't putting out enough energy to interrupt flowering, at least in usable bands, it started to flower and is committed to finishing, or there is some auto-flower genes in there that he's not aware of. His extrapolating his experience with the black light to saying that only red light regulates flowering seems very unfounded. Just from the way he talks I can guarantee I have done way more research on the topic of light spectrum and photosynthesis, and have yet to see him give one shred of scientific evidence, or a source, which corroborates what he is claiming.
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I agree fully with your feelings on the black light completely. He has put forward all sorts of wild ideas between this thread and his "Green Light Spectrum" thread based on three grows he has pulled off using this "technique". Unfortunately, it doesn't seem like he's even tried it any other way for comparison.

Here's a quote where he say that plants won't flower using only a blue light source:

"that does not tell me anything i know that but you can grow a plant with just blue light. im not saying do this but you can.the plant will veg. it does not need full spectrum light to grow right?but cut the light to 12/12 they still dont flower why? its dark the now its dark why they dont flower?"
 
Unnk

Unnk

Well-Known Member
okay i just read both threads and wow man... okay the reason you can leave your black light on during flower cause it is filtered glass the uvb radiation coming through will induce a bit more thrichrome density but i can tell you this they arent getting enough photons from the black lights to even photosynthesise anything a regular cfl is gonna produce more because of the less sever filtering. Im just saying quick trying to say its factual because quantum physics has tons of experiments proven in THEORY but nothings factual everything is subject to opinion so i take what you say as a opinion lol
 
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ricardezra

Member
Alarm Clock said:
You can flower under only blue light. It's not preferred, as it's generally agreed that the red end of the spectrum produces fatter buds while the blue end is better for leafy, vegetative growth. If you are saying you can't get a plant to mature to flower by using only blue lights, you are wrong.

Try to find some metal halide only grows.

At least homebrewer tried to support part of what you were saying. Sorry you missed it.
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have you ever tried it? well i have foolishly not knowing what I was doing I got no flowers I dont know what I did wrong but nothing. they were weak also
 
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ricardezra

Member
Unnk said:
okay i just read both threads and wow man... okay the reason you can leave your black light on during flower cause it is filtered glass the uvb radiation coming through will induce a bit more thrichrome density but i can tell you this they arent getting enough photons from the black lights to even photosynthesise anything a regular cfl is gonna produce more because of the less sever filtering. Im just saying quick trying to say its factual because quantum physics has tons of experiments proven in THEORY but nothings factual everything is subject to opinion so i take what you say as a opinion lol
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what do you think im saying?leave on with no other light? or just when the lights go off?
 
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ricardezra

Member
freddiemoney said:
I agree fully with your feelings on the black light completely. He has put forward all sorts of wild ideas between this thread and his "Green Light Spectrum" thread based on three grows he has pulled off using this "technique". Unfortunately, it doesn't seem like he's even tried it any other way for comparison.

Here's a quote where he say that plants won't flower using only a blue light source:

"that does not tell me anything i know that but you can grow a plant with just blue light. im not saying do this but you can.the plant will veg. it does not need full spectrum light to grow right?but cut the light to 12/12 they still dont flower why? its dark the now its dark why they dont flower?"
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hey I have tried blue light before foolishly a time or two before. I have more than three grows under my sleeve. I say 3 cuz does are my most productive ones.so when i did my research i got better.now with my study on light spectrum I find that plants use light to tell time.so i was like ok cool.now it measure light but how?do you know?they way your talking I dont think so.all you do is nothing no real imput at least i am trying
 
moash

moash

New Member
ricardezra said:
have you ever tried it? well i have foolishly not knowing what I was doing I got no flowers I dont know what I did wrong but nothing. they were weak also
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mmaybe u just were not patient enough
i have flowered plants with 6500k cfls
and i have also vegged with 2700k cfls
u need to do more reseach in places that know what they r talkin about
 
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ricardezra

Member
moash said:
mmaybe u just were not patient enough
i have flowered plants with 6500k cfls
and i have also vegged with 2700k cfls
u need to do more reseach in places that know what they r talkin about
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you mean soft white cflS? im not, Im saying blacklights i used blacklight only and messed up bad. my first couple of grows
 
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