# far red light, simulated dusk during flowering



## sweetarded (Aug 20, 2011)

read something today about hitting the plants with 2 hours of far red light (say from a 2800k incandescent up high) right after your main lights go off. this simulates natural dusk and stimulates production of the flowering hormone sooner each night.

the physics make sense to me, but i don't know about the biology. can anyone shed some light on this?


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## cannawizard (Aug 20, 2011)

*what flowering hormone does 'dusk' produce on cannabis?


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## darkdestruction420 (Aug 20, 2011)

Flowering hormone is always present, however it is destroyed by light. that prevents it from building up high enough to start flowering during longer photoperiods. i suppose it may make the level building up at night a tiny bit faster as the lighting isnt as intense but even if you were to increase that hormone by giving an extended dark period to build up that level it doesnt matter once its to a level high enough to trigger flowering adding more hormone doesnt equal faster flowering, thats why we cant go and say give only 8-10 hrs of light a day to speed up flowering.


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## Wetdog (Aug 20, 2011)

cannawizard said:


> *what flowering hormone does 'dusk' produce on cannabis?


Those dusky whore moans are the best.

Wet


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## sweetarded (Aug 20, 2011)

darkdestruction420 said:


> Flowering hormone is always present, however it is destroyed by light. that prevents it from building up high enough to start flowering during longer photoperiods. i suppose it may make the level building up at night a tiny bit faster as the lighting isnt as intense but even if you were to increase that hormone by giving an extended dark period to build up that level it doesnt matter once its to a level high enough to trigger flowering adding more hormone doesnt equal faster flowering, thats why we cant go and say give only 8-10 hrs of light a day to speed up flowering.


did some research. the flowering hormone is florigen, and it's actually two different chemicals. a signal chemical is produced in the leaves, and another chemical is produced in the buds, and when they meet it becomes the flowering hormone.
the leaves start producing that signal when the nights get longer. if you tell the plant "nighttime has now begun" with a simulated dusk, just like outside, the leaves will begin producing that signal chemical sooner each night, meaning each bud spends more time receiving the flowering hormone.
even if it doesn't help i don't see how it could really hurt, incandescents are awfully dim to plants


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## darkdestruction420 (Aug 20, 2011)

where did you read that? i;d like to read it myself. ive looked into it more myself and everything ive found supports what i said but ive got an open mind.


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## sweetarded (Aug 20, 2011)

https://www.greenpassion.org/index.php?/topic/26033-florigen/
http://en.wikipedia.org/wiki/Florigen

http://www.integralhydro.com/flowerdragon.html says:
"Florigen was, until recently, a mythological flowering hormone. The discovery of the molecular nature of florigen was a major scientific breakthrough in 2005.The discovery was made due to DNA technologies, combined with molecular biology/plant physiology research, whereby the florigen gene was isolated in flowering/fruiting plants. Florigen is probably a small protein called FT. FT is produced in the leaves and is transported via the phloem to the shoot apical meristem (SAM). FT acts like a molecular &#8220;alarm-clock&#8221;, evoking a complex genetic scenario, which culminates in flower formation. The process seems to involve red, far-red, and blue light, the length of the night, and the plant&#8217;s biochemical clock. There is still much to be understood about florigen and there is no single ubiquitous hormone that can be used to mimic the florigen response. Genetic research has succeeded, to some degree, in developing mutant hybrid strains of tomato whereby florigen levels were successfully manipulated (through select breeding), inducing early flowerset, and larger and sweeter fruit. This, however, needs to be done at a genetic level (I.e. breeding or through other mechanisms which are far too complex to go into). Put simply, there is no product in a bottle that can trigger (&#8220;speed shift&#8221 florigen in a plant."

So, no nutrient additive. But spectrums of light-- that's something we already control.


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## sweetarded (Aug 20, 2011)

this thread has good stuff in it too: https://www.rollitup.org/advanced-marijuana-cultivation/40388-phytochrome-infrared-interaction-2.html although their focus seems to be on infrared energy (heat) which is usually a PROBLEM for indoor gardens, so i don't understand why they'd want to add more infrared light. if the room is hot, it's full of infrared energy. 
i'm focusing on the spectrums available at dusk (/dawn?). but, some very relevant info is in this thread


Kief Reefer said:


> SgtPeppr,
> 
> To answer why a higher temperature might work is this: Infra-red light is beyond the human visible spectrum, but not a plants. All energy is in wavelengths, even light energy which is considered a photon, both a particle and a wavelength simoultaneously. What plants "see" as far-red or infrared, we "feel" as heat. It is both technically and essentially identical. We can only feel infra red because our eyes are not adept to the wavelengths in that spectrum, but phytochrome "sees" infrared in the same way it does red. The presence of red light will convert phytochrome to the Pfr form, which in itself triggers other auxins, but not the one in question. Florigen is the hormone for flowering and is triggered by critical amounts of Pr, that is when we turn the lights off there is no more red light to make Pfr, but there will always be infrared light in the form of what we call heat. So all the Pfr converts to Pr and triggers florigen to starts flowering the plant. Where we as guerrilla/indoor/outdoor grower's can go with this information is very limited because of our resources. We can't play with cannabis genetically but we can see the effects of our actions. What would a temperature of 5 degrees higher with a lower relative humidity at night in the flowering room do? What could we deduce from an infrared scan of a flowering room in the day vs in the night? What would it reveal about the amount of heat dispersed in the room? These things I want to know.



EDIT:

after reading through that thread and some other shi online, heres what i think is up (mad rep to kief reefer is he's still around):
the phytochromes (light absorbing substances of the plant) Pr and Pfr are affected by far-red light. They're actually the same thing; but red light changes Pr into Pfr and far-red/infrared(heat) light changes Pfr into Pr. 
At night, Pfr slowly changes back into Pr, because the only energy present is infrared (and far-red at dusk).
Pr is more responsible for actually triggering flowering, Pfr is more of the plant's clock, it's always running. Higher levels of Pr stimulate flowering sooner each day and with more vigor.
The conversion from Pfr to Pr happens every night, regardless of veg/bud cycle. More Pfr converts to Pr the longer your dark period is (the longer less red light hits the plant).
A low-k incandescent bulb up high right at "dusk" would help kickstart the conversion of Pfr in Pr, because the energy is mostly far-red and not red-red. after two hours (real dusk length) you can turn the lights off, and let the conversion occur on its own.

That's what I think I've gotten out of this so far.

phytochrome/pr/pfr info: http://www.mobot.org/jwcross/duckweed/phytochrome.htm


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## bob harris (Aug 20, 2011)

Ed Rosenthal has an article on this. A burst of far red at lights out reduces the plants "change over" time to the night mode by about 2 hrs. The advantage would be that you can run 14/10, allowing more lights on time for photosynthesis to occur...without disrupting the flowering cycle.

In essence, the first 2 hours of "night" the plant is adjusting to dark..the the far red burst somehow puts the plant immediately into dark mode. 

Here's the link..in another article he talks about how it works indoors...

http://www.cannabisculture.com/v2/content/2011/04/18/Ask-Ed-Questions-and-Answers-Light-Deprivation-How-Ditch-Tarp


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## sweetarded (Aug 20, 2011)

awesome! thanks man. idk why more people haven't heard about this. if it's accurate then you could do a 14/10 and get more instead of less like you said

i'm pretty sure i was wrong in saying it should be on for two hours, 'flashing' the far-red just replaces two hours of darkness. 
but, how long should the far-red stay on? he doesn't really say.

http://en.wikipedia.org/wiki/Twilight#Civil_twilight
http://en.wikipedia.org/wiki/File:Types-of-twilight-en2.svg
looks like, 12 hours of sunlight over 180 degrees would be 15 degrees per hour, and 'twilight/dusk' ends when the sun is 6 degrees below the horizon, so about 30 minutes of far-red light.
but that's all physics math; not botany math, so i don't know.


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## bob harris (Aug 20, 2011)

In the article on indoor growing..he says the 'flash' is litterally like 5 minutes..the key is it has to be a specific color..730 nm...you'd need led's or a pretty specific bulb...but the way it works out is that by going to 14/10..you grow 17% faster because of the increased 'daytime".

Another way to increase growth rate is to go to a 21/12 light schedule for a week. Usually around the second or third week in flower.

the theory is that the plant needs the dark period to be long enough..but doesn't care about the light period being longer. In a week you've added about 5 xtra days of growing time. I've done this, and it does accelerate growth..but it's a pain in the ass. You have to set your timers manually every day. if you could find a 7 day programmable digital timer, it would be easier.


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## sweetarded (Aug 20, 2011)

where do you see 5 minutes?


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## PetFlora (Aug 21, 2011)

Assuming it only needs to be on for a short amount of time, it seems that you need a separate timer and fixture (and where will it be placed?). As importantly, how much wattage is needed to cover say 2 X 4, to be effective?

hth


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## sweetarded (Aug 21, 2011)

i guess you would place the bulbs in the same place as the rest of your lights.. even dispersal over your plants. the bulbs that would be used for this purpose don't need ballasts, most of them screw into a regular incandescent socket, and you can get sockets with plugs for pretty cheap. and yeah it would need a separate timer.. so would adding UVB during midday

here's an infrared LED bulb right around 730 nm, they say it covers between 2 and 4 sq ft, but it's $150.
http://www.alphahydroponics.com/ecc-frfarredledgrowbulb.aspx

and here are some infrared 730nm LEDs alone (you' have to wire em up to a controller and a wall adaptor)
http://www.ledtronics.com/Products/ProductsDetails.aspx?WP=1737 product *L200CWIR730-24D*
i'm not sure how much space they cover, but they're $6 apiece.


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## sofresh420 (Aug 21, 2011)

Do you think Red Fluorescent T5s would work?


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## sofresh420 (Aug 21, 2011)

Do any of you plan on doing any experiments anytime soon? I want to see the results


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## puffenuff (Aug 21, 2011)

I don't know if it's true, but I added far red lights to my grows under the assumption that they would increase growth rates and make the flowers denser. I put them in the corners of the room shining down at angles and I definitely feel like those getting direct exposure to the far red came out more dense. That's what I found out from my first grow with them but I still have more experimenting to do.


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## sweetarded (Aug 21, 2011)

sofresh420 said:


> Do you think Red Fluorescent T5s would work?


i think the red in them would keep the Pfr from becoming Pr, even though they have far red. the conversion requires only far-red and infrared light, red will interrupt it

i found a parabolic heat reflector at the thrift shop today, i'm gonna look into it before i buy it, but i do plan on doing some experiments.


edit:
http://www.gopresto.com/downloads/instructions/07912.pdf ---infrared heater, normally $80+, i found it at the thrift shop for $25! totally gonna buy that and disable the "convenient" footlight. should easily cover my 4x4 canopy with infrared light. once it exists.


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## PetFlora (Aug 21, 2011)

Far Red is hard to find in T5s these days. Let us know if you find a source. Maybe someone out there has some left over inventory


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## bob harris (Aug 21, 2011)

You would need a separate "circuit'..and I have no idea how much far red wattage you would need. That's the main reason I haven't played with it. 

My set up is over complicated already..2, 600's on 12/12, plus 3, 175 watt Mh aquarium lights on 1 hour after and off 1 hour sooner then the hps ( 420-460 nm blue light..Keeps internodes tight and the plants have great color and vigor, 
don't think it helps yield, but the plants look healthier ) Then I have 4, 26 watt 10.0 uvb bulbs that run on yet another timer. I start the uvb out at 15min per hour, and increase to 8 full hours a day by harvest. And YES uvb excites trichlome coverage...a bunch.

I am NOT recommending anyone to try this, I've grown the same strain for years...and developed this schedule over time..lots of "opps" figuring out what this strain likes. 

one thing I have learned...EVERYTHING is strain specific, as far as maxing results.

I grow DJ Shorts flo...It's very sativa dominate in it's growth and effects, and finishes in less than 40 days in my room...good yields too for a "moderate" yielding strain..3.5 oz per plant usually.... But indicas hate my room..or maybe I haven't figured out how to grow indicas...


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## puffenuff (Aug 22, 2011)

These are the far red led lights I use, 15w each and only $80.

http://www.advancedledlights.com/products/SpectraBoost-Grow-Spotlight-%2d-15w-High-Intensity-LED-Grow-Light.html


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## sweetarded (Aug 22, 2011)

wow, they say it covers 6-9 square feet too. thanks man


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