Blue light at night the controversy rages

Any bulb with a disclaimer will do:

CAUTION: This lamp emits strong blue light wavelengths (470nm - 400nm), which have been shown in some studies to harm the retina. Avoid prolonged use of this product if . . .

you are taking photosensitizing medication such as nonsteroidal anti-inflammatory drugs (NSAIDs), most antidepressants, some antibiotics, diuretics, and beta-blockers and other heart medications;

you have a pre-existing ocular condition such as macular degeneration;

you are diabetic or otherwise at risk for retinal damage; or

you are 55+ years of age.


Blue Led's are available in the specified wavelengths. Night time wattage is about 40-50 watts per 1000 watts daytime.

Research via web, various sites, 4.5 minutes.

Thule said:

I thought it was green light that the plants can't use and blue spectrum equals daylight. I'm actually using a blue energy saving lamp for flowering right now, so I find all this hard to swallow. Do blue leds really differ that much from light bulbs with a 6400k spectrum?

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In this discussion, for *me*, it would be helpful to know if we're talking any light that appears blue (to us) or if we're talking about a specific wavelength or wavelength range. So, with specific regard to LEDs, what 'blue' are folks talking about when they say 'blue?'

Let me see if I have some of the papers on plants using green light. Spurr had posted some papers a few years ago on another forum that I thought I'd saved and I haven't got them! Worse yet, I can't find them via Google Scholar and am mostly finding aquatic/marine articles. And...! I can't find the damn papers.

SeaMaiden said:

In this discussion, for *me*, it would be helpful to know if we're talking any light that appears blue (to us) or if we're talking about a specific wavelength or wavelength range. So, with specific regard to LEDs, what 'blue' are folks talking about when they say 'blue?'

Let me see if I have some of the papers on plants using green light. Spurr had posted some papers a few years ago on another forum that I thought I'd saved and I haven't got them! Worse yet, I can't find them via Google Scholar and am mostly finding aquatic/marine articles. And...! I can't find the damn papers.

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thats exactly how i feel. i am not throwing lights into flower before i know what wavelengths will work. no sense in bombarding them with light that will freak them out.

Tonygreen said:

Now those are done using red at night. The blue light would activate chloropyll B. While the red light would activate chlorophyll a. From looking at the chart it appears more chlorophyll b is used by blue light than chlorophyll a is by red at certain wavelengths.

View Image

I see some people had issues with reveg usin the reds, the blue would avoid this it seems?

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We should be able to kind of extrapolate and educated guess by looking at the charts for plants and light.
We obviously dont want to use a light that just appears to be blue if the hypothesis is that red promotes/controls flowering and blue light does not affect the flowering.
If red is for flowering you can see that it affects chlorophyll a and where it peaks.

The rational would be to use light in the narrow spectrum that chlorophyll a is at its lowest. I THINK.

My thinking would be between 450-500 nm.

You can kind of see where blue absorbtion peaks for chlorophyll B chlorophyll a is least active.

Well thats my idea anyway, thats how my brain sees this possibly working. (read on I was a little off on thinking it was just chlorophyll a+b)
(it looks like the important thing is chlorophyll b can photosynthesize, chryptochromes are triggered by BLUE light as well, coincidently (or not) both are affected by the blue light)

Here is a science paper for everyone and especially LED guys. http://www.lightinglab.fi/enlighten/publications/internetui_akvile.pdf

So cryptochromes are what is affected by blue light it seems, from my reading phytochromes are the initiator of flowering affected by the red spectrum.

So I guess we would be getting action out of the cryptochromes at night from the blue light but the NO red wavelength so phytochromes are unbothered in their balancing of PR and pfr.

suzy cremecheese says

"The pigment phytochrome detects the presence or absence of light. This is how plants measure daylength.

When phytochrome absorbs red light with a wavelength of about 660 nanometers, the small protein that is attached to the phytochrome changes its folding. This changes some of its properties. For instance it becomes more hydrophobic and binds to membranes more easily when it is in the refolded state. Also it now absorbs light in the far red spectrum of 730 nm. When this form absorbs the far red light it refolds in its original form and the properties revert back to less hydrophobicity and it releases from any membranes it may of bound to.

Pr = red absorbing /660 nm
Pfr= far red absorbing/ 730 nm

Pfr reverts to Pr in darkness.

If far red light is given quickly enough after red light, phytochrome does not have enough time to affect cell metabolism and has no effect on the plant.

If the far red comes long enough after the red for the presentation time to be fulfilled, the Pfr is able to complete the transduction process and the far red light no longer cancels out the red light stimulation.

This is how critical night length is determined by the plant, the amount of time in darkness required to induce flowering. Cannabis is a long night plant therefore the night must be longer than the critical night length in order to induce flowering. In the case of cannabis the Pfr doesnt come for 12 hours (at least it dosnt in your closet) and now it no longer cancels out the red light stimulation and flowering is triggered."

If I got it down right that protein balance is what control the buddin....

So we are tryin to mess with chryptochromes with the blue light while leaving those protein controlling phytoreceptors alone in their regualtion of pfr and pr.

wiki link :0 (may as well know wth we are messin with if you dont already)

http://en.wikipedia.org/wiki/Cryptochrome


I think the answer is here in all this info Philthy and Sea, sorry if this is a difficult read,,, smokin delicious atm.

trichrider said:

Summary

Cryptochromes are photoreceptors that regulate entrainment by light of the circadian clock in plants and animals. They also act as integral parts of the central circadian oscillator in animal brains and as receptors controlling photomorphogenesis in response to blue or ultraviolet (UV-A) light in plants. Cryptochromes are probably the evolutionary descendents of DNA photolyases, which are light-activated DNA-repair enzymes, and are classified into three groups - plant cryptochromes, animal cryptochromes, and CRY-DASH proteins. Cryptochromes and photolyases have similar three-dimensional structures, characterized by an α/β domain and a helical domain. The structure also includes a chromophore, flavin adenine dinucleotide (FAD). The FAD-access cavity of the helical domain is the catalytic site of photolyases, and it is predicted also to be important in the mechanism of cryptochromes.
http://genomebiology.com/2005/6/5/220

these are present in every cell and tell the cells whether or not to repair themselves. i'm doubting the ability to fool these cryptochromes with any light.

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I think we need not fool them but use a wavelength of light that phytochromes regulation of pfr and pr is not affected by.

The wavelength where blue light is maxed out on absorbtion would be the place to be as phytochromes are no affected by that wavelength.

I think the chryptochromes are what we want to be affecting not fooling! It seems the phytochromes are what we want to sneak by... If I got this right...

Cryptochromes are known to possess two chromophores: pterin (in the form of 5,10-methenyltetrahydrofolic acid (MTHF)) and flavin (in the form of FAD).[16] Both may absorb a photon, and in Arabidopsis, pterin appears to absorb at a wavelength of 380 nm and flavin at 450 nm. Past studies have supported a model by which energy captured by pterin is transferred to flavin.[17] Under this model of phototransduction, FAD would then be reduced to FADH, which probably mediates the phosphorylation of a certain domain in cryptochrome. This could then trigger a signal transduction chain, possibly affecting gene regulation in the cell nucleus.

Right in that max blue absorbtion range appear to be where its at.

Here is the research data that growblu has done as far as wavelength and spectrum data so far

https://growblu.com/research-and-development/spectrum-research

I just noticed all of those today LOL so I am happy to have found it myself. It has veg and flower spectrum data among other data on there. Most I haven't looked at yet BUT others might find it interesting as well.

After rethinking everything I have been reading my hypothesis is



That spot would give let chlorophyll a + b photosynthesize light at a fairly descent % compared to normal "daytime light". If pfr and pr regulation is what is controlling flowering

Pr = red absorbing /660 nm
Pfr= far red absorbing/ 730 nm

Pfr reverts to Pr in darkness.

and the balance between the two is what regulates flowering then we would be specifically in the 380-450 range with the night light not interfering with normal pr/pfr cycle/balance.

Hypothetically.

We are really fucking with natural order now. hehe. The end results may depend on the plants response to all the extra energy. Since it is in flowering will a portion of the extra energy go into calyx production etc. or all of it into stem and leaf? If so would the extra leaf and better circulation then maybe produce more calyx or thc production? Lots of questions there too. Hopefully we learn more soon.

everything looks perfect on paper though tony

and then comes the test data

sweeeeet

I think a blue at night test would be perfect for a ufo sized panel, maybe a micro grow that has a 12/12 flip between red and blue.

Now the question is, which strains or sativa/indica leaning plants LIKE to have certain blues on at night and also if certain plants like certain blues or many different wavelengths could be played with during the night cycle.

Tony you could always do a diy micro panel testing your "BAM" theory and let us know how it grows for you. I have to research what blues I have in my panels before I get into this test myself and am excited to see what others come up with as well.

What would be sweet is that the growth is just so amazing due to the double light schedule the damn plants grow stretch marks LOL

It's probably true that the whole "green light" thing existed before LED lights had the ability to emit bright, very specific wavelength light. I have been working on a freeware program called Lightput that would allow you to do all types of fun plant light experiments using a DIY LED array and a DMX controlled LED driver, and a power efficient computer with a backup battery like a netbook would be ideal. I would do it myself but I'm far too busy with Lightput and other things already

The Light sequencer only has 12 steps, but each step can be set for over 2 hours, so set the beat time to 2 hours (7200000 milliseconds) and set your night time to blue only (12 hour night that would be 6 steps, 6 hour night 3 steps, etc.) you could really elaborate on the experiment using Lightput, by for example, having the level of blue light slowly fade to a dim light before the white and red lights come back or the other way around. Probably best to keep it simple at first though.

In the future I plan on making a 24-hour timer mode that will work even better for this.

check it out here

http://www.lightput.com

I think a side by side if possible would be best. You could readily see differences.

If you had 2 DMX controlled Lights and you could set one light to channels 1-4, and the other light channels 5-8 or something, you could have your whole Lighting setup being controlled like that for an easy way to do a side by side comparison. Then if it works you could use that setup to side by side other ideas like sneaking some green and cyan in throughout the night maybe? Thats starting to sound really expensive though.

edit: you'd need a dmx splitter too, there are DIY kits like the lynx splitter that are kind of hard to get, i found a cheap already assembled DMX splitter on Amazon for $35 though, some people want way way too much for DMX signal splitters, like $500 and up! Maybe I'll look into support for multiple USB RS-485 devices in Lightput as a way to split the signal. Theres a small chance it already works that way, I only have one usb rs-485 device to test with so I don't know. There's an even better chance it would be really easy to change it if it doesn't work to send the same signal down all connected rs-485 devices instead of one, the FTDI programming interface has tons of features. Plus assuming many "DMX splitter/ amplifiers" are like the Lynx splitter design, they are basically just a bunch of rs-485 chips sending the same signal down different lines anyway, so this would esentially make your computer the DMX splitter.

I just ordered a second FTDI RS-485 device and a Raspberry Pi, Getting multiple RS-485 devices to send the same signal and work on a Raspberry Pi would allow someone to have high control over the lighting in 2 rooms, controlled by a computer that only uses about 6 watts!

Hopefully I'll get that running soon, anyone got some lights and room to test this with? I wonder if theres ways to control flower stretching using amounts of blue and or green light.

EldoLED makes great drivers for this kind of setup that are very efficient and support up to 55V on a Line of LED's, which allows you to string over 12 LED's not in parallel, meaning you could run at least 24 LED's in parallel off one DMX control circuit, the powerdrive 562 has 3 control circuits. They are about $100 for the AC powered version and are very reasonably priced considering that a single constant current driver often costs around $30, this is 3 of them in one, all three of them support more LED's than many $30 drivers, and they are controlled through DMX communication. The only downside to these is if you want to program the driver yourself you have to buy a "tool box" for almost $200, but most drivers arent even programmable.

The driver is default set to run at 350mA but you can change the output of each channel individually if you had a toolbox or one of their more expensive drivers with the control panel built in, up to 1,050mA. You can also edit the default lighting when the driver is not receiving a DMX signal, which it would be usefull to set the driver to retain the last set of DMX info in the event of a dropout to prevent unwanted light changes. As far as I know, these drivers are also self-terminating, which means it should be easy to reduce or hopefully totally avoid unwanted light changes with these drivers.

what you'd need to do these tests if you had to buy and assemble everything:

2 x POWERdrive AC, 50W, DMX, 3 control channels, 3 output, constant current, $105 each (shop.eldoled.com)

2 x MakersLED 24" heatsinks (not entirely necissary, but very nice equipment) $100 each (ledgroupbuy.com)
(alternatively you could just get at least 1/8" metal sheets, maybe with some heatsinks mounted to it, and either drill holes to mount the leds or use 2 part thermal compuond to cement the LED's to the metal, but this is not recommended, especially if using LED's powered above 350mA)

LED's (12 for each light)
24 x Royal Blue (ledgroupbuy.com has CREE XT-E Royal Blue for $3.25 each, 2100mW version which is very good)
24 x Red (ledgroupbuy.com has CREE XT-E Red for $3.50 each)
24 x Warm White (ledgroupbuy has cree xm-l LED's for 6.50 each)

2x FTDI based USB RS-485 devices for communication, about $30 each on amazon

...so that's about $788 so far without the shipping, you'd also need small odds and ends like thermal compound (the one part stuff if using the MakersLED fixture) power adapter for the fans included with the MakersLED fixture if you need to use them, mounting hardware, etc. (one downside to the makersLED fixture, that thing is heavy) Not to mention all the grow tents, etc you might need for this.

anybody with room in their house for this want to try to get funding for this on kickstarter? perhaps you could be testing this on tomatoes, the data would still be interesting and then you could use it for weed eventually.

Thats just an example of a test too, it would be great to use a 4 channel Driver and use red and far red, using far red only an hour or 2 before lights out to test that whole thing. Or perhaps have the far red slowly increase throughout the day until the last hour.

I will also prioritize the 24-hour timer mode to have better control, right now if you use the light sequencer it automatically fades between 2 beats, so if you have 2 beats, one that is full on light, and the next one is full off, it wont actually get to full off untill the end of that 2nd 2-hour beat. alternatively you could put it on blink mode that would abruptly change from full on to off at the time of that beat change. Something in between, like a 5 minute slow fade on the first 5 minutes of the two hour beat might be good, but the 2 hour slow fade might be good too, but blurring the line between day and night.

double post of excitement, my bad (delete this)

Nice analysis Tony.

In the examination of what's the proper light for this, it seems there are two main factors.

1. The night time light source must not generate any photons with a wavelength of 660nm. This is an absolute, and probably eliminates all light sources except LED.

2. Ideally the light wavelengths used at night time should maximize light absorption by chlorophyll to maximize sugar production. Whether the relative proportion of light wavelengths maximizes photon absorption by either chlorophyll a or chlorophyll b, it is uncertain as to the effect of this relationship on flowering. Sugar is sugar though.

Actinic tubes emit only wavelength at 420-430nm. A bit easier to source, and cheaper at the moment as well, perhaps. Be careful which actinics you use, though, as some do have phosphors in the mix that produce some push toward the middle and red end of the spectrum.

Here's a good one, IMO.
http://www.marinedepot.com/D_D_Gies...ting_Systems-GL2131-FILTBUT5HO-GL2135-vi.html

Kickstarter, that is an interesting concept, fund my experimental grow room!

I reckon we could get some analysis from starting at 380nm or so where a +b equalize and working our way up in side by side or recurring tests.

LEDgroupbuy.com also has these true violet LEDs rated to emit 390-430nm light, they are bridgelux LED's though which are generally not as efficient as Cree's or Philips' LEDs... so many red-less possibilities...