# LED grow lights



## Oznog

I kinda wanna try an aeroponics setup for growing lettuce, tomatoes, spices, blah blah. Really. Not pot. I want tasty vegetables. I seldom buy lettuce because I make 2 sandwiches and throw the rest away in a week. If it's growing I'd just trim what I need and let the plant keep growing the rest of the leaves.

Just checking in on this. Is there any benefit to LEDs compared to CFL/HPS (high pressure sodium) lights? I saw something on being able to select the wavelengths the plants actually need. The installation could be versatile, I could mount the LEDs on flexible stems to arrange them as needed. Then again getting thousands of lumens in LEDs is pretty expensive. On the other hand I can get a LOT of Rebels off of Future Electronics for the hundreds (~$400) it costs for proper HPS growlights.

Does the photosynthesis/watt with LEDs actually go up above CFL/HPS results? I know LEDs are not remarkably better than CFL/HPS in terms of _lumens_/watt (and generally worse actually) but if photosynthesis only uses certain wavelengths out of the CFL/HPS output then I could see where color LEDs could produce more results per watt by producing only the wavelengths used. Less heat could be produced too, making a cooler growing environment which is better.

I tried to Google this and got a lot of pages of people selling shiat, whom I was not inclined to believe. Anyone have proper knowledge of this?


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## LukeA

Oznog said:


> Really. Not pot.



I have a friend who asked me to build a grow light for pot. I declined.

I don't have any proper knowledge, but it would seem to me that plants would like any light that isn't green.


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## Oznog

Yeah actually green is the wavelength the plants DON'T need. If they used it, it would be absorbed not reflected. It is unproductive to generate these wavelengths, it's wasted power and heat generation at the light and some of it will be turned into heat at the leaf. I know IR would just be dissipated as heat at the leaf and shortwave UV is surely damaging to the tissue not helping.

There are a bunch of charts showing there's two peak centers of usage, one in the blue range another in the red-orange. Apparently both are needed, there are descriptions of how the balance serves different biological functions and makes them grow vs flower or something but so far the pages sound like pseudoscience- trying to _sound_ scientific in the lack of any actual data or scientific understanding. Basically speaking out of their asses.

Wikipedia says photosynthesis uses only 2% of the visible spectrum then "[citation needed]". Well, if one could give it only what it needed with LEDs that could in theory make LEDs a far superior choice. But this is Wikipedia.

I'm also unsure of whether a couple of tight bell curves at the red-orange and blue ranges will actually serve all the biochemical needs. The usage graph shows SOME absorption in other wavelengths... I wonder if they're essential biochemical steps of the photosynthesis process which would fail without small amounts of these wavelengths?


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## Illum

it would be a very expensive....and very tedious experiment...

I can say with confidence though....X1, Y0, YA, and X0 luxeons kill plants in a short time [all leaves turn white, a surefire sign that chlorophyll is dying out....] luxeon Cyan doesn't work either


NASA has been using LEDs to successfully grow plants in space...supposedly they use some UV lights in combination with the visible spectrum....but due to the widespread exploitation of using the LED for illegal operations, the information that can be valuable for agriculture is now a trade secret for drugsellers


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## LukeA

Oznog said:


> Yeah actually green is the wavelength the plants DON'T need. If they used it, it would be absorbed not reflected.



I know. I said so. Plants reflect green light, they don't absorb it. They absorb other wavelengths.


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## Oznog

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

Well I'm looking at this, it's getting interesting. It's no surprise then that white LEDs would kill plants, the wavelengths feed the mid-400's area ok but supply next to nothing for the peaks in the mid-600's range.

There are two peaks to service, one at around 450nm so a Royal Blue can supply that. Royal blue produces few visible lumens/watt but that's an eye sensitivity issue. Rebels' Royal Blue are rated in mw output which shows it's around 25% efficient which is "neat". Actually the top chart's breakdown shows that chloro-b's peak... ouch, Rebel-cyan almost hits it but no its tight line at 505nm is only "close". The Relative Power Distribution graph shows that it's at 0.6 relative power at 490nm and chloro-b's peak is down from 85% to 40% at the 505 peak emission of the cyan.

On the other side there's a peak need around 670nm which is difficult to meet with LEDs. Well Rebel-red would feed chloro-B's peak but not chloro-A. That 670nm peak is longer than red LEDs come in! I looked up Cree XR-C Red and it's like 635nm. The next step up is IR LEDs and that's way TOO long.

Reading up on photosynthesis, it appears this proceeds in 2 stages (the "Z-scheme"), and I assume each of those high/low wavelength peaks corresponds to a stage thus without _both_ you have nothing. I don't know the difference the 3 photosynthesis types makes for each plant. Lettuce, tomatoes- do they need A,B, and carotenoids? How much?

The highly peaked nature of the graph IS promising. In theory if we could meet like 4 key spectral points, you could grow on a tiny fraction of the power since the process is so unresponsive to all that stuff in the middle.

Now I see why some pages suggested it as a _supplemental_ since LEDs can't provide the longwave for chloro-a. This leaves unanswered questions. Specifically, I mean this shows absorption but not need to complete the 2-step Z-scheme. Could the process need a whole lot in the shortwave stage and just a little boost in the high end that a small CFL could fit? 'Cause that's possible. Do some plants have a lot of chloro-a vs chloro-b vs carotenoids?


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## Sable

I have two habanero peppers growing under a CreeBar hosting a RebelStrip from the Shoppe.

The RebelStrip has alternating red and royal blue Rebels from Future (Thanks, Wayne!) and is driven by a 750ma Xitanium.

It's working out almost supernaturally well.


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## Oznog

Huh. And that's the "red", not "red-orange"?
One red to one blue, alternating?
How many Rebels total?
Is there any additional light involved? Room light?

We had a discussion awhile back that running Rebel red or red-orange much over 350mA is almost pointless. The higher thermal impedance of this technology combined with the high efficiency loss at elevated die temps means there will not be a lot of additional light output even though at 700mA it's at 250% power (doubled current + increased forward voltage). It makes more sense to use more Rebel devices.


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## Stillphoto

Check these out
http://www.homegrownlights.com/

I actually found them while looking for some other indoor led lights. These seem to be what you need and are pretty cheap if you get the kits and solder it yourself.


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## snarfer

Looks like there are through-hole LEDs in 660nm. For example Lumex SSL-LX30448SRC, which is available from Digikey. 

I remember reading a few years ago about a Dutch company that was using an LED system to grow produce underground. Seriously, not pot, it was in the newspaper. They had a system where the plants were put in little carts and sealed up in there. The LEDs were inside the carts, and the carts traveled slowly down a long track over a period of 4 to 6 weeks. At the end of the track the cart was opened and the produce harvested. 

Of course the produce was probably completely tasteless like everything else in the Dutch supermarket.


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## knabsol

Hi!
This has been discussed here before so you can always pick up an old thread in this if you want some more information. I´m on the process building one for trying it out. I´m using the luxeon rebels. If you want more info I can allways post some pics and data later.
Good luck!


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## Gryloc

Oznog,

Go ahead and try it out. I found that royal blue emitters and a red-orange emitters work very well at keeping plants alive. …And it was not for pot. 

I was in town a few months ago when this kid, who had a handful of picked four leaf clovers, handed me one of them. I thought that was pretty cool. So, when I got home from work, I decided to revive it because it was already limp and dead looking from the heat. So, I fashioned a mini plant holder, which consisted of a beer-cap and some looped wire soldered to it to support the tiny stem of the clover. Then I pulled out a spare royal blue rebel that I had (from a unique LED jewelry project) and a half-completed taillight project, which consisted of 3 red-orange rebels on a Cree star. I wired both in series to my CC bench power supply, and hung it about a foot over the picked clover. The red was overwhelming, so I only used one of the three r/o rebels in series with the royal blue.

So, with only 200mA of current going to both r/b and r/o Rebels at 0.3m, and a slight dribble of water in the beer cap, the clover perked right back within hours! I continued to give it water sparingly, and reduce the current down to about 20mA at night (200mA in the day). Surprisingly, this picked leaf lived for about a week before I noticed that the clover started to get “mature” (where the green darkened in the daylight, and the cells looked like they lived past their prime). Eventually, it died after a week (got limp and collapsed). I think that it lacked nutrients, or maybe the leaves just lived their longest. I am no expert on field plants, so I do not know how long to expect a few leaves to last.

I can imagine with a nice array of Rebels (r/b and r/o), your few lettuce plants will grow well. I also heard that the reds were used for the reproductive system, so I do not know if it is even required to grow plants strictly for consumption and not expect to collect seeds. It would be cool to actually be able to enjoy the tastes of food that got its power to produce food from LEDs. While you are at it, test most of your plants with the r/b and r/o LEDs, then maybe one or two with just royal blue. It would be neat to see what is required just for sakes of harvesting.

Do not forget that the royal blue and red orange LEDs make the leaves look black (normal) and lifeless. The light may be distracting if it is near where you work due to the odd colors (I got used to it). Have a white light source nearby to check daily how your plants are growing. You would need it to check to see if the tomatoes are becoming a healthy red, and if your lettuce is a nice green.

I plan to extend this experiment to grow more plants (venus fly traps and not pot). I found a light fixture at a PetsMart for reptiles that produce a large amount UV-B light. I got it but have not found the specs to see if the light peaks match that of photosynthesis. It uses two 9W 9” U shaped fluorescent bulbs. It is very small, but I hope it works as well as those coral grow lights (which I did not get because they are large linear fixtures). I may resort to making an array from what ever Rebels or Luxeon 1W or 3W emitters that I can find for cheap. The royal blue Rebels are more efficient than the old Luxeons, so I will just have to compare and buy what ever works best.

Good luck with the project. I hope you continue with the project since they Rebels are relatively cheap and easy to power (with low currents). I wonder if 12 blues and 12 reds will suffice… I guess you have to determine the actual light output of each LED color (depending on the array), and match it to the needed lux needed to grow plants. Then, you can adjust the emitter count and fixture distance to the plants accordingly. Maybe you can try using cheap optics to focus the light onto the plants (like the super cheap reflectors from KD/DX). Please post pictures with your updates. I want to see the fruits of LED light, and to see how the finished plants compare to store-bought.  That would be awesome! Thanks.

-Tony



EDIT:

BTW, this neighboring thread in the LED section may help determine how well your red and blue LEDs fill the light gap in your spectrum for photosynthesis...
"*Spectrographic analyses, pg. 3":*
https://www.candlepowerforums.com/threads/200385
I remember seeing this at the LED museum long ago, but forgot about it. It is convenient how it sort of popped back up for you due to some updates.


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## Oznog

This actually started because of a thread elsewhere about silly as-seen-on-TV products. One was the "Aerogarden", a cute countertop garden. 

Googling it shows that, except for the high priced seed kits, it *actually* works, and quite well! Grows damn fast. It is not hydroponics but aeroponics. Aeroponics leaves the roots suspended in air and mists them frequently. Aeroponics has been shown time and time again to be vastly superior to hydroponics. The initial $120-$200 price isn't all that bad but the "seed kits", well as my dad said, "that's how they git ya". Hahaha $20 for 7 seed pods of _one_ type (except for the spices where you get several types). $20 would have bought a LOT of Romaine or tomatoes at the store! Ya people have already figured out how to make baskets and support medium so they can get it growing without that stuff. It's actually a bit funky because the pod needs to support the weight of the plant entirely since the roots are in air underneath. It would simply sink through a bit of starter soil and fall over or fall through.

Well naturally the next step of planning is hacking an existing one or hacking a whole new setup. There's some stuff on the internet about DIY for sure, making it into a big Rubbermaid container, the tough part being building a reliable mister that won't clog. Then weird changes like this LED thing come up!


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## Oznog

Gryloc said:


> EDIT:
> 
> BTW, this neighboring thread in the LED section may help determine how well your red and blue LEDs fill the light gap in your spectrum for photosynthesis...
> "*Spectrographic analyses, pg. 3":*
> https://www.candlepowerforums.com/threads/200385
> I remember seeing this at the LED museum long ago, but forgot about it. It is convenient how it sort of popped back up for you due to some updates.



Huh. It looks like the older red LEDs have a lot looser wavelength distribution, AND they're a longer wavelength, into the 675nm chloro-a longside peak. Interesting but it's hardly economical to produce light with hundreds or thousands of ancient low-output LEDs. 

I'm still not sure how this works. Will it grow the same if we don't meet all 4 peaks of chloro-a and chloro-b? I saw where carotenoids are a different thing, responsible for some specific nutritional content. So leaving out the growing wavelengths for that would be bad, but it looks like the Royal Blue's gonna feed that nicely along with the chloro-a's shortside peak.


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## Oznog

Hmm. Well, Google shows widely varying recommendations of about 1000-10,000 lumens/sq ft, courtesy of the marijuana growers' dumping of info on the web. Let's throw a figure out there that the LEDs are 10x more productive per lumen and a middle-of-the-road 5,000 lm/sq ft x 2 sq ft growing area.

Btw, I would like to remind all that we ARE still talking about lettuce and tomatoes here. Really. Maybe strawberries. Surprisingly, there is no emoticon for "_not_-winking" as in "take this literally not wink-wink".

So, I need like 1000 color lumens. Well, I *can't* translate those lumens into royal blue mw. Ouch. Huh. I can make 1000 lumens with 25x 40 lumen 1W red Rebels. Again, I'd like to assert that reds should generally not be run above 350mA the returns are not really worthwhile. Well, I'm guesstimating the royal blues are more efficient and do more important work so it *may* require less but that's speculation, well, more speculative than these other speculations anyways. So I'm just gonna throw out the figure of 25x devices total, some red, some blue. Doing the Spidereye-6x boards really we're talking about 4x well-sunk Spidereyes here. 

I did see some scientific evaluations showing photosynthesis has limits. That is, once you reach the maximum illumination needed per sq in of leaf, more will not help because the process is limited by the biological capabilities of the plant. However, there will be gains in ensuring that all the leaf area gets illumination and that's a trick since some leaves shade others, etc. I guess that's where reflectors come in.

The lambertian distribution troubles me, this is hard to deal with except to cover the surrounding area with reflective foil. The Spidereye concept isn't going to work with any OTC optic to make a focusable beam. If we place it 3" from a big plant then we'll exceed the photosynthesis limit locally on ONE part of the leaf, wasting the light power, whereas further out the leaves don't get enough light. Yet if it's place 2 ft away the leaves will get even light but there will be a significant amount of uncaptured light off to the side.

Running a 2sq ft garden off 25W, that's amazing. Even if I'm off badly in my estimations, 50W would still be amazing. This is hardly a lot of power. My refrigerator to keep the lettuce I bought at the store cool uses more than that. It won't heat up the growing area, which is good because I don't keep my house really cool in the summer and lettuce likes cool growing temps or the leaves won't be crispy. At least that's what I read, I've not tried to grow it even outside.


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## tsask

NASA has made some inadvertent strides here. Minor cuts heal faster in presence of some light frequencies, blue/red?. They have also made advances growing veggies.

For anybody reading this who has other intentions, the US Govt has placed enforcement at the top of the priority list. It is possible to get more prison time for an "illicit grow operation" than violent crimes like rape, murder etc. Stick to LED grown broccholi sprouts and life will be good.


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## VanIsleDSM

tsask said:


> NASA has made some inadvertent strides here. Minor cuts heal faster in presence of some light frequencies, blue/red?. They have also made advances growing veggies.
> 
> For anybody reading this who has other intentions, the US Govt has placed enforcement at the top of the priority list. It is possible to get more prison time for an "illicit grow operation" than violent crimes like rape, murder etc. Stick to LED grown broccholi sprouts and life will be good.



Yeah.. that's because the US govt is more concerned with the tax dollars they're missing out on than people's actual safety. Everyone knows alcohol is a far more destructive substance. I imagine it would be much safer to grow a little bit though, than it would be to try and buy it. I've heard that here, 4/5 cultivation charges don't even make it to court.. but BC is known for it's leniency in that area.

I've seen a couple documented comparisons of LEDs to HPS, but none with proper high power LEDs. The HPS did better, same amount of watts, than the red/blue LEDs, but they were only 5mm guys. I think with some rebels, could be just as good as HPS or MH anyway.. it's just getting reds that are deep enough.. too bad there wasn't a high power LED between IR and RED.. that's what you'd want.

Of course the best way would be some mirror and lens system to focus daylight inside your veggie box.. and then only turn lights on if you need more daylight than you're getting at the time.


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## red_robby

I've looking into this for a little while myself, I found a pretty useful link

http://environment-center.blogspot.com/2008/07/growing-plants-with-leds.html


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## Gryloc

Really quick on light requirements:
Convert the lumen output of those figures from google to actual power output. Lumens are a solid unit (if they were measured correctly), but you would have to determine how many mW of energy of a certain color is required to create 1 lumen of humanly visible light of that color. There are lumen to radiometric power conversions somewhere I believe (I think).

So, find the spectrum of those similar to what those HID or fluorescent fixtures produce, and then find how many lumens (roughly) are produced from the certain reds and blues. Then, convert that to actual radiometric power for each, scale that number a bit for your sized veggie growing "operation" lol (serious face when laughing), and finally use those numbers to determine what is needed of the red and blue emitters.

Finally, the Royal Blue Rebels are efficient, as the Red/Oranges are about the same as they were a couple years ago, so why not use the Luxeon III R/O emitter? It is a beefier package that can handle more current, and produce around 190 lumens of red/orange from one emitter! You may need to spread that heat around a bit by using a thin copper heat spreader on the base of your existing heatsink (due to the higher W/cm^2 density), but it may save you a few bucks and make the red lighting less complex (with less parts). The Rebels may be your thorn because you may need many more of those. Did you check on the royal blue TFFC K2s? Maybe you can get more light density from one of those (like how you can by using the 3W R/O's). Just a suggestion. 

Now I got to leave my workplace before they turn off the lights on me (atleast rush-hour will be less severe... slightly)

-Tony


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## Oznog

Neat. I looked around and once again the pot growers are a useful source of info. High Times magazine found this 80W "UFO" thing here did grow plants competitively well with a 400W HID. Well they were obviously growing pot but I'm assuming that if it can grow that functionally then it'll grow lettuce well too.






I'm curious what LEDs those are. I think there's supposed to be 80x 1W emitters here. They kinda look like they could be the sq 4-pin Superflux lights. They look far too close together to be 1w Luxeon emitters or anything but I'm not sure of the actual scale of the thing. Hmmm... might be questionable if this is actually an 80W fixture, and in any case we care about lumens out (in desirable wavelengths) not watts in. So it's really important what the device's lumens/watt actually is. Does this seem a bit small and enclosed for AlInGaP whose output drops off quickly with elevated die temps? 'Cause I don't see a clear intake-outlet differentiation on those vents which might suggest there's just a fan on the board or sink stirring things around rather than flowing.

They're unfocused lambertian devices by the look of it, unless they're actually just a bunch of 5mm T1-3/4 devices. They're claiming it's "directional" which does support the T1-3/4 hypothesis. Which would be... lame for $599. But it couldn't be 1W/device at T1-3/4, could it?

Actually based on the device's thickness and LED density I might suspect they've got a PCB carrying SMD LEDs. Maybe Cree XR-C or any of the small SMD LEDs out there- they come in 1W. But that would result in extremely poor dissipation using just board traces which would smother the output efficiency of AlInGaP-based devices.


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## Oznog

Gryloc said:


> Finally, the Royal Blue Rebels are efficient, as the Red/Oranges are about the same as they were a couple years ago, so why not use the Luxeon III R/O emitter? It is a beefier package that can handle more current, and produce around 190 lumens of red/orange from one emitter! You may need to spread that heat around a bit by using a thin copper heat spreader on the base of your existing heatsink (due to the higher W/cm^2 density), but it may save you a few bucks and make the red lighting less complex (with less parts). The Rebels may be your thorn because you may need many more of those. Did you check on the royal blue TFFC K2s? Maybe you can get more light density from one of those (like how you can by using the 3W R/O's).



Naw, remember the Spidereye-x6 I came up with? That changes everything. You have a similar lumen/watt, this is true. But one 6x unit has a net thermal impedance of 1.7C/W, compared to 10C/W of the StarIII! And 240lm _when driving it at the conservative baseline 350mA level_, remember a growlight will see thousands of hours of service. And just the fact that we only have to deal with mounting ONE Star (and sinking 6W of heat). 'Cause I hate drilling and tapping the aluminum sinks.

Costwise, with Future's volume discounts, the 40 lumen Rebel types are actually _cheaper_ than the StarIII per lumen. So, it looks way more cost effective, bottom line.

I did find this plant lumen growth chart for aquarium plants. Interesting, they don't show the 500-600nm to be completely useless like the Wikipedia entry suggested. I've seen a similar diagram elsewhere. I have to speculate again on what this describes. I mean, a plant clearly reflects green! So could it be that it uses 25% of what it absorbs, but reflects 85% anyways, meaning the net utilitilization of the light is only 3.75%? I suppose if you had a mirrored room the reflected light will get a "second chance" but it is gonna be poor utilization.

The 92% red/8% blue seems to be used in the other products I've seen.

I did see things on how different wavelengths (even infrared, which is not supposed to have a part in photosynthesis) affects stem growth/height, the way a stem turns towards the light, and flowering. I dunno, it might be more pseudoscience gobbledygook. Red is supposed to promote flowing, and tomatoes need to flower to fruit. But again royal blues are POWERFUL for their cost, they used to be the lest powerful/$. At least in terms of mw of photons made. *if* they could be the powerhouse of vegetable growth then they'd be the way to go, but apparently the current makers of LED growlites either don't think so or the blues were simply too expensive in the past.

Doesn't someone here have a kid looking for a most excellent science project? Growing stuff under different wavelengths? Damn this summer vacation!


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## coolwaters

i made one but its only 7 LEDs. 3 blue, 3 red and 1 white. i tested it on my strawberry plant and it grew pretty fast.

you would need a lot more then 7 LEDs/21w. your talking about over 400w of LEDs for a good growth and good coverage.

red light promotes flowering and blue promotes overall growth.
small plants with lots of fruit = more red light.


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## Oznog

So, I wonder... lettuce doesn't flower. Just blue??

Your 400W estimate probably isn't consistent with the size I had in mind. The Aerogarden can grow lettuce effectively, that's proven, with 2x 26W CFL growlights and no significant room light supplementing it. So 52W for this small garden. May or may not constitute the maximum light the plant could use. LEDs should produce usable PAR (Photosynthetically Active Radiation) at more effective wavelengths. I'd kinda hope this would be at least 2x better per W. The 10x better theory... well, it _might_ be possible but probably fantasy. I really don't know what to expect.

I had to think about how much energy we're actually delivering to a plant.
So I found this table which shows lumen/W. Apparently they used Photopic, Scotopic numbers were impossible. So a Rebel Red-Orange-0050 50 lumens at 617 nm delivers 192mW of light. Royal Blue-0275 delivers 275mW at 455nm (no table needed, that's already rated in light energy).

So the blue is 43% more mW. Now, it's probably not relevant but shorter wavelengths are higher energy photons and thus fewer photons per mW. On that basis, I get like 5.5% more photons out of a royal blue. 

I know that photoelectric effects waste the extra energy of photons above the photoelectric threshold in solar cells. In that case the photon count of usable photons would be everything. However, since photosynthesis is a more complicated collection of various processes, I'm assuming the plant probably gets more utility out of the absorption of a high energy blue photon than a lower energy red photon.


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## VanIsleDSM

Why red/orange? Plants much prefer the deeper reds.


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## Oznog

Well, like I said, the deepest "red" I see getting masses of economically would be the 627nm red anyways. That is near (but not "on") the spike for the chloro-a's response, but chloro-b's longside peak just doesn't have a modern LED that can hit it. Too long for LEDs.

I just picked up the RO for calc by chance. Yeah, I'd actually choose the red if I was gonna do this. The red... doing "proper" interpolation (which I didn't do before), I get 195mW for the 40 lumen @ 627nm. Interesting, so it's really the same power as the 617nm red-orange, just in a less visible wavelength.


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## Gomer

http://www.thorlabs.com/thorProduct.cfm?partNumber=LED661W
670nm LEDs :-D Just need to find a high power version


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## blasterman

The theory is that longer wavelengths encourage different growth in plants because it tells the plant different things about competing vegitation. For instance, an abundance of shorter wavelengths can tell the plant there's nothing over-head in terms of tree canopy, and to grow in one direction. Not enough longer wavelengths, and it tell the plant there's a lot of competing plants growing densely around it because the setting sun's rays (more red) are being blocked. So, the plant responds by growing denser roots to get a better footing and grow taller.

I don't grow dope or anything, but am simply an avid green thumb. I use supplimental light indoors because I live in a northern state, and my current plant-champs are 5500-6000k compact fluorescents. You know, the nasty white-blue ones you see at hardware stores sold under the pre-text as 'Daylight'. They are ugly one the eyes, but plants love them. HID is inefficient because they 'spray' a very large spectrum. Brute force approach, but I reserve HID for marine aquariums.

While this seems like a cool idea to try, I don't think LED would be as efficient as CFLs. Why? For one thing, LEDs are a very specular light source that emits from a single point. Not a good thing for growing plants unless the plant is very small, or small the leaves far away. Where the LED might do a better job is if it were on a swing arm, or something where it could be moved around to illuminate different parts of the plant on a daily basis just like the sun. This is really what encourages faster plant growth.


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## Oznog

Indeed, I am envisioning having some flexible stems each with a Rebel Spidereye-6x Star and like a CPU heatsink. Could make an array of these and position them to irradiate it from a number of angles. I guess a reflective blanket around it would help too since these spill a lot of light off to the side.

I see where Marubeni makes a 670nm LED, 450mW radiated power with 2.35W in. It's a 60-chip device and surely way outta my dirt-cheap price range for this silly project.

HID is well known for being significantly more efficient for growing than CFL. Well, apparently for pot growers anyways. Legal or not, they seem to have the science down and their research is solid. But they're after large scale stuff. Nobody needs an expensive HID to light an aquarium, that sure would be a bright aquarium! A small lettuce/strawberry/tomato/spice garden might be economical to use HID depending on size. But the LED idea is more fun.

But I don't know if LEDs can realistically beat out CFL or HID. It's a fun question anyways, isn't it?


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## Oznog

Apparently these guys selling the "LED Grow UFO" didn't invent and manufacture it domestically:
http://www.manufacturer.com/business/search?isnew=all&type=SellLeads&keywords=LED+grow+lighting%2C+grow+lamp(LED+UFO)

Hmm found SOME products (panels of crazy numbers of T1-3/4, not UFO-type) are using 660nm LEDs (LEDs which I can't seem to find). Saw this:


> The LED's that are DEEP RED 660nm type are ESSENTIAL for mediatingthe Phytochrome Flowering response...anyone selling panels or lightswith JUST 625nm Orange that tells you they are perfect for flowering isnot telling you the whole truth...
> 
> 
> The 625nm Orange is an important wavelength for fast, efficient growth.
> 
> 
> Finally the 465nm Blue is ESSENTIAL for strong leafy growth and thick stem development..
> 
> 
> 
> RED 660nm LED Grow Light is ESSENTIAL for those needingto flower plants - without it you don't get a strong Phytochromeresponse.




That wasn't a "UFO" thought. Trying to figure out which wavelength the "UFO" uses is unclear, there appear to be copycats. In one place I saw "

652nm (RB mixture)". WTF... they like averaged the red and blue wavelengths or what?? Another says "645nm (RB mixture)".


Another site says "630nm" unambiguously (had another figure for blue) for the red on their UFO ... which is _really_ into the orange range. But another says 660nm for their UFO.


I Google around and see there are 650-660nm LEDs around though. Nice!


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## snarfer

> Nobody needs an expensive HID to light an aquarium, that sure would be a bright aquarium!



Nobody except, evidently, reeformadness.


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## karlthev

Sure isn't any of MY business but, a helluva lotta work and $ here for a lousy tomato or two in my opinion! Don't you have a yard you might be able to use? I used to start all of my tomatoes, peppers and eggplants first on a propogation mat and then transfer the seedlings under flourescent lamps--half "cool" and half "warm" in coloration and then, finally to the garden. Now THIS was a bit of an undertaking but, I did my own canning ("jaring") and would put up 100+ quarts of tomatoes plus many other vegetables. Getting vegetables to mature under "artificial" lighting is quite a costly proposition. Interesting but costly I'd say.....



Karl


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## knabsol

Hi Karl!
I can only speak for myself and why I am doing this project for myself. So far it´s been costly mostly standing still since I have other projects that needed more attention. But my goal is to be able to grow some sallad and spinach in my kitchen. I´m living in an apartment so there isnt much garden to speak of. Though an option would be to go to the supermarket and buy them. But I´m also doing this to learn about led controlling, pwm and so on as well as plants and how they behave under different light and if it is possible to grow under leds. So it´s mostly because I need something like this to learn about new things and maybe I can use this knowledge later on?
Well that´s only me  Later this year I will be living in a house with a small garden so who knows...maybe I will have frogs under it instead...
Cheers!


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## karlthev

Well, there's the answer! I hope you get an outside place to grow your veggies. I found no matter what light combo I used inside, the growth spurt realized when tomatoes were transplanted outdoors was amazing. Ya just can't beat the sun! Good luck on this one, some combination will work I'm sure and you'll get quite an education to boot in the process!



Karl


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## coolwaters

Oznog said:


> So, I wonder... lettuce doesn't flower. Just blue??



i guess red just makes them really fat =p and blue really tall and skinny

btw i notice people here have hundreds of really expensive flash lights that they dont really use so why you people complaining about the cost of something your going to use?
:shrug:


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## Oznog

Well, I wanted to start with aeroponics to begin with for low water, high growth, bug-free growing.

Yeah there is some irrationality to it. Even a couple hundred bucks investment would by a lot of lettuce and tomatoes. But coolwaters nailed it... most guys here spend hundreds and hundreds on a flashlight they use for a few hours and the job could easily have been done just as well with any light from Wal-Mart. I dunno, the solid state-to-food process is just fascinating here.


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## Stillphoto

Plus who knows...pesticide free organic home grown veggies might even be better for you! Plus if you were to buy similar organic varieties at the market, they would add up pretty fast.


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## coolwaters

if your spend enough money and time it can pay off.

increase plant growth to 1000% along with efficiency.
those crappy florescent growing bulbs got nothing on LEDs.


mine just isnt strong enough for a field.

mix that with hydroponics and you got your ultimate growing system.


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## saabluster

Saw this story and it reminded me of this thread. Thought it would make sense to have this info here. "Typical 10 watt package performance of up to 2 watts of radiant power sets new records for Deep Red products and enables high radiant power density for the horticulture market."


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## ericjwi

coolwaters said:


> i made one but its only 7 LEDs. 3 blue, 3 red and 1 white. i tested it on my strawberry plant and it grew pretty fast.
> 
> you would need a lot more then 7 LEDs/21w. your talking about over 400w of LEDs for a good growth and good coverage.
> 
> red light promotes flowering and blue promotes overall growth.
> small plants with lots of fruit = more red light.



I just finished a 16 CREE array that only cost about $50-60 in parts up to this point. However I do need to do something better to pull the heat off of it 

My main project is 56LEDS but thats going to not be finished for probably months and it does have deep reds. None of the currently marketed lights include deep red though and still the 100+W high power LED ones perform really really well on most plants. They seemed to have problems with cucumbers though... www.greenpinelane.com


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## Oznog

Yeah Mouser carries the LEDEngin. They're expensive though. But be sure to evaluate as mw of rated power instead of lumens. 660nm scores terribly on the lumen scale compared to red-orange even if the emitted mw was identical. The nonisolated thermal pad is not as desirable as the isolated devices. Isolated thermal pads are awesome esp for larger arrays.

LEDEngin specs 650mW for 5W in (13%) on the deep reds... IIRC the normal reds are like 20% efficient. But, well, apples to oranges. It's a different tech. If the photoactive response peak is several times higher as shown then it should be more than enough to make up for the difference in mw and be much more efficient in terms of photosynthesis per watt. Also... and I'm not clear on what the charts used for a measure- photoactive response is often evaluated in terms of response per mole of photons (einsteins) since any reaction step is always triggered by a photon on a 1:1 basis. Deep red is more photons per mw thus (if used) can cause more photoreactions. Well, 660nm vs 630nm is only 4.8% more photons per mw though. The difference in mw per lumen between 660nm and 630nm is far more significant.

I did look up some of the "UFO" and grow panel mfgs. SOME appear to use "deep reds". Others do not. This might explain some of the confusion and inconsistent reports as to whether these work or not. Seeing as they come out of China and are poorly documented, I bet even some of those sold as "deep red" might not be, and if they don't perform well people will be reporting grow LEDs as poor performers.


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## greenlight

> *Power meets efficiency
> with LumiGrow ™ LED grow lights.*
> 
> *Go Green. Save Green.*
> Indoor gardening experts select LumiGrow LED grow lights to protect plant health, save money and reduce carbon footprint.


This might be worth checking out just to see what else people are using. I talked to the owner, he says he uses 5w luxeons because he can get them for a good price and they put out a lot of light.


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## Oznog

greenlight said:


> This might be worth checking out just to see what else people are using. I talked to the owner, he says he uses 5w luxeons because he can get them for a good price and they put out a lot of light.



And that's probably an example of a mfg with a problem. Sounds like he's selecting based on visible lumens rather than PAR, which is a mistake. Granted I don't have experience trying this growing yet, then again many of these people are simply saying "it grew things" without a controlled experiment to show what grew better than something else. I believe the PAR charts are important here and that shows the value is in Deep Red.


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## ALICIA21

Oznog said:


> Yeah actually green is the wavelength the plants DON'T need. If they used it, it would be absorbed not reflected. It is unproductive to generate these wavelengths, it's wasted power and heat generation at the light and some of it will be turned into heat at the leaf. I know IR would just be dissipated as heat at the leaf and shortwave UV is surely damaging to the tissue not helping.
> 
> There are a bunch of charts showing there's two peak centers of usage, one in the blue range another in the red-orange. Apparently both are needed, there are descriptions of how the balance serves different biological functions and makes them grow vs flower or something but so far the pages sound like pseudoscience- trying to _sound_ scientific in the lack of any actual data or scientific understanding. Basically speaking out of their asses.
> 
> Wikipedia says photosynthesis uses only 2% of the visible spectrum then "[citation needed]". Well, if one could give it only what it needed with LEDs that could in theory make LEDs a far superior choice. But this is Wikipedia.
> 
> I'm also unsure of whether a couple of tight bell curves at the red-orange and blue ranges will actually serve all the biochemical needs. The usage graph shows SOME absorption in other wavelengths... I wonder if they're essential biochemical steps of the photosynthesis process which would fail without small amounts of these wavelengths?





There are a bunch of charts showing there's two peak centers of usage, one in the blue range another in the red-orange.


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## Cactus Bastard

ALICIA21 said:


> There are a bunch of charts showing there's two peak centers of usage, one in the blue range another in the red-orange.


Yes, that's what we've been talking about actually


Oznog said:


> In theory if we could meet like 4 key spectral points, you could grow on a tiny fraction of the power since the process is so unresponsive to all that stuff in the middle.


Another factor to consider (with regards to PCs at least) is that LEDs put out lighting that is actually constant . Fluorescents flicker at varying frequencies above what the human eye can detect, in order to provide what appears to us as consistent lighting. A plant does not have any complex optical system smoothing out the lights for them. They are simply absorbing the raw energy. 


ericjwi said:


> the 100+W high power LED ones perform really really well on most plants. They seemed to have problems with cucumbers though...


That concerns me a bit.. Different spectrums will affect different plants differently. Also, the whole thing about _how_ they affect things is a confusing issue as well. How some plants have adapted to associate differing lighting conditions with different forms of competition from neighboring plants.. 

Also, I strongly agree that even when using LEDs to fill in the key spikes, a smaller fluorescent tube filling in some of the other wavelengths could be very beneficial indeed.


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## Torbeam

Take a look at these

I will make an attempt next season with 10 different chilli peppers!


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## Oznog

Torbeam said:


> Take a look at these
> 
> I will make an attempt next season with 10 different chilli peppers!


]

That's the common 640-660nm red. It has the same problem as all the other "normal" reds discussed here- it misses the 680nm response peak (only hit by "deep red" devices) and I don't think it's gonna be a very good performer.


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## thegeek

This place has some 680nm emitters in relatively high power packages, they have a minimum order though. 

http://www.tech-led.com/High_Power_Illuminators.shtml

If someone were interested enough to do a group buy I would be in for a couple. I just don't have the ambition or time to run one myself.


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## Oznog

IIRC the tech-led is really expensive and seems to be an old, off-brand tech.

LEDEngin seems to be best supplier of Deep Red, Mouser carries them which makes them vastly easier to get and the price isn't too bad. The problem is the nonisolated thermal path.


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## Julius

snarfer said:


> Of course the produce was probably completely tasteless like everything else in the Dutch supermarket.


I had to register for this forum if only to respond to this bullcrap statement.
I've never been really fond of living in The Netherlands, I have not been born here and both my parents migrated out of the NL ages ago. For long periods of time I've stayed in Thailand, Cambodia, China, Malaysia, several places in Afrika, Canada, The US, The UK, Germany, France, Italy, Belgium, Jersey Island, Tenerife, Serbia-Montenegro, Russia and Norway, but never ever did I encounter better tasting Supermarket content as there is available here in The NL!

Now, of course your taste can be your taste alone, but to claim 'everything' is tasteless in Dutch supermarkets sounds to me like you either have never been in one, or didn't develop the power of taste, because truely, that claim is utterly ridiculous and false.
Here in Amsterdam I can buy practically *every* available taste that exists in the world in countless supermarkets, and all pretty near to where I live, even. In addition to that, most average Dutch supermarket food has much more taste than what you'll ever find in other countries. The chocolate and snacks alone are the best you can find worldwide.

Furthermore, the cheese available in Dutch supermarkets is the best tasting cheese one can find, by far. You won't find anything remotely close anywhere in the nations and areas I mentioned above, including the US. Even Dutch goat-cheese tastes much better than the French one, who claim to be king at that.

I've never been one to defend the country I live in, but what you state there is a pure misplaced lie. You probably assume all Dutch citizen use drugs and wear wooden shoes too, right? Kind of like the Fox News idiocracy you suffer from in the US. *[moderation: abusive comment removed. - DM51]*


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## DM51

Welcome to CPF, Julius.

We'll allow you your patriotic (but off-topic) rebuttal of snarfer's post, although you might want to note that he posted it ~18 months ago, and you've just resurrected a somewhat obsolete thread. It's sometimes worth looking at the date of these things before you reply to them.

What we can't allow, however, is the last sentence in your reply. You may attack the post, but not the poster. Please would you therefore edit your post to remove that sentence.

The thread may contrinue on condition that it returns to discussing the topic, with no further distractions...


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## blasterman

I just want to jump in an rehash my skepticism over the need for far red (>640nm) LEDs with growth lights. 

Reason for this being that the proven benefits of HPS and the orange/pink spectrum of that light source would seem to contradict the need for far red.

As for the rather heated side-bar that Julius responded to, I live in West Michigan which has a huge Dutch population and culture, and there are countless Dutch run produce stores and eateries close to my home. I wouldn't call Dutch tastes 'bland', but they do emphasize dairy/white grains over spices, etc., and this I think tends to contribute to the opinion of ethnic Dutch food as being rather blah to other tastes. A better term would be 'practical'. The Dutch owned dairy I was in last year was white wash clean and vastly more humane that the horror stories you see on the news.


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## Kevinwells

Hi,
this is Kevin from LumiGrow. I saw your posting and I thought I would talk a little about your last comment re red/orange and hid lighting.....

We released the first version of our product using 640nm peak red LED's. One year later we upgraded the LED's to 660nm LED's and the difference was night and day. 

We dramatically improved the performance of our light. some of that was just adding more LED's (we added about 40 watts of white to help users see their plants ) But the real difference was the red.

We had our light independently tested. UC Davis did the plant growth tests. They found the light performed equally to a 600 watt HPS in a greenhouse. 

We also did spectroradiometric testing and compared it with an Eye Hortilux 600 watt HPS bulb. Our light had 10% more blue and 3% more red at 660nm. 
In contrast, our original model using the 640nm led's had about 30% less red at 640nm than the HPS. (HPS lights have a high yellow orange content)

We continuously run tests in our labs. They have shown that it is not just the red, but the wavelength of the red that matters. The same light, with 660nm LED's, produces about 45% more flower buds than the 640nm peak wavelength LED's. Our test plant was Chrysanthumums, a sun loving, short day obligate plant. Our tests using lettuce, showed no real difference but lettuce is less sensitive to red...
I hope this helps clarify the subject.


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## thepaan

Plants have two photosystems (PS): I and II. They also have two major chlorophylls (chl): a and b. PSII contains mostly chl b where PSI contains mostly chl a. PSII uses light energy to free electrons from water and feeds them to PSI. When one PS is stimulated less than the other (below light saturation) then it becomes the limiting factor in photosynthesis. When PSII is the limiting factor the system is relatively stable but when PSI is the limiting factor then the electrons in PSII get backed up and eventually damage the PSII D1 protein.

To answer a question several posts up: chl a and b both have a peak in the blue and the red. Although the blue peak is usually shown as higher than the red peak, the red peak is much better at driving photosynthesis.

The difference in night and day between your 640 and 660 nm LEDs is because with the 660 you have a better balance of light between the two photosystems. Though, I would still like to see an LED grow light with two red wavelengths - one at 650 and the other between 670 and 680, with a ratio between 1:3 and 1:6 former to latter.


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## Julius

Hmm.. my measurements and research shows me that the two major frequencies (where you want the peaks to be at) are 428 nm and 664 nm, for underwater plants anyway.
The rest of the spectrum will easily be fed from simple cheap white and warm white LEDs, and aren't really much of an issue if you ask me. Most artifical plant-growth lighting situations will already have those areas from the spectrum in sufficient amounts around, I would guess..


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## Julius

I found an interesting thread:
http://www.thekrib.com/Plants/Tech/lighting.html
saying that the color of light does not have more than 10% importance (where 100% is the total lighting for freshwater aquarium tanks).


> In 1982 Philips Corp. did a lot of experiments in order to find out the effects of different light colours on aquarium plants. The following plants were used (because of their fast growth):
> Hottonia inflata
> Limnophilia sessiflora
> Ludwigia natans
> Bacopa amplexicaulis
> Hygrophilia polysperma
> Rotala macandra
> The surprising results were that the influence of colour was less than
> 10 percent!
> 
> 5) The results are applicable for all aquatic plants because all aquatic
> plants
> contain the same type of chlorophylls as the land-based plants.
> Algae contain additional chlorophylls that are not found in higher plants.
> From McCree's experiments it is obvious that these additional chlorophylls
> are responsible for the sensitivity to blue light.
> 
> Bottom line:
> ============
> 
> It does not matter what colour of light you provide for your aquarium
> plants. Choose a colour that makes it look good for you.
> If you are not interested in algae (fresh water people usually are not)
> you can additionally try to avoid the blue part of the spectrum
> (or keep it to a minimum). This also means that high light temperatures
> (>5500K or so) are better suited for a salt water aquarium.
> ---> Your mileage may vary.<---


This contradicts my personal findings quite a bit.
My experience clearly shows that, for example, the famous plant Cabomba, thrives under the blue 428 nm peak, and even searches for it. When I noticed this, I tried the same on other plants, and practically all showed similar results. They *want* the 428 nm to be there, preferably lots of it.

If anyone knows more about this, I'd be happy to know what others experience.
I wonder how these experiments by Philips from 1982 were executed. Did they use color-lense-filters, or actual colored sources of light?


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## blasterman

> I would still like to see an LED grow light with two red wavelengths - one at 650 and the other between 670 and 680


 
I just blast lost of energy at 615-625nm, (70/30 red/blue at 460nm), and have excellent growth for *everything*. Same analogy as HPS, which is a known working technology devoid of far red.

Maybe we should get loudspeakers and tell the plants on repeated loop they should respond to wavelengths we determine in the lab, not in an actual commercial greenhouse


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## Inkidu

greenhouse ------------artificial lights

Two things that have next to no relevance to each other.

That is to say I never walked into a local greenhouse with lights in it. 

The whole point is you take advantage of the sun to grow your plants.

A large commercial greenhouse that use artificial light (hps) I would assume do so for

very specific reasons. The spirit of the thread is are leds a viable solution in a small aeroponics application. 

And one main reason they could be considered for a person trying to grow a few plants

in there house is the cost and trouble of trying deal with the heat that HPS and MH produce. 

Here is another way to say it just because what ever is used to make a Mcd........ burger

works for them doesn't mean it works for me in my frying pan.

Hope this helps.


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## Inkidu

What importance if any can be given to the CRI #. (for growing)

Seems to some extent that a grower would want to simulate 

natural sunlight as much as possible. Whether that is the most 

efficient thing is another ? (colored leds) I have been eyeballin 

http://www.tech-led.com/data/SMB660N-1100-01.pdf

They also mention a 680nm but the radiant power falls off 

and the power put into is quite a bit different compared to the 660nm

version. Efficiency is always a concern for me. 

http://www.tech-led.com/data/SMB680-1100-I.pdf

Anyone order from this company? 

Thinking of, to save money, mounting them on top of a small piece 

of copper or al with insulating epoxy. Just big enough for the heatsink

portion of the led. I am fairly new to this but isn't this how some flashlight

leds are mounted i.e the heatsink pad is epoxied and the overhanging leads

are connected? 

Would I want a ceramic pad between the led and heatsink both options

are available from this company i.e. the I suffix is added? 

I am far from an expert so any help would be appreciated.


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## kaichu dento

Inkidu said:


> greenhouse ------------artificial lights
> Two things that have next to no relevance to each other.
> That is to say I never walked into a local greenhouse with lights in it.
> The whole point is you take advantage of the sun to grow your plants.
> A large commercial greenhouse that use artificial light (hps) I would assume do so for
> very specific reasons. The spirit of the thread is are leds a viable solution in a small aeroponics application.
> And one main reason they could be considered for a person trying to grow a few plants
> in there house is the cost and trouble of trying deal with the heat that HPS and MH produce.
> Here is another way to say it just because what ever is used to make a Mcd........ burger
> works for them doesn't mean it works for me in my frying pan.


First, welcome to CPF! 

The reasons for using lights in a commercial greenhouse, or any greenhouse for that matter, is to maximize growth on cloudy days, to extend the growing season and assure the plants are getting the light they need early and late in the day. 

For growing indoors without the benefit of a greenhouse makes it even more important though!


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## Inkidu

Thanks for the greetings.

"For growing indoors without the benefit of a greenhouse makes it even more important though!" You are joking with me right?

So I need lights indoors.

How does anyone use LED as an indoor grow light? 

I don't know it this helps Oznog but I am trying to figure out the same thing

as far as if colored led can have benefits as far as being more efficient than

white light. Personally I am leaning towards a high power mixture.

I am trying to use a combination of warm white led and deep red led.

My present application is of all things to grow algae as a filtration method 

for a fish tank. As a general statement I am sure that input would help for 

any type of plant that you are trying to grow under led lights.

My particular application has been shown to do well 

with light that emphasizes the red spectrum.

I am presently building a setup with ledengin 660nm and Marubeni 680 nm

with cree warm white xp-g and xp-e 470-480 blues (the blues fill in where

the warm white cree spectrum falls off)

I personally believe, that while it might be difficult to use generalities about

what led lights are effective, a productive discussion can be made about

what LED work 1st hand for anyone trying to use a LED indoors. 

Hope this helps and would appreciate a productive discussion on what

LED work to grow plants indoors.

Thanks for any help.


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## blasterman

> My present application is of all things to grow algae as a filtration method for a fish tank


 
Take it from 20 years of reef tank experience - all your need is lots of blue light and sufficient nitrate / phosphate.

Long red wavelengths have been proven inconsequential for underwater growth because the spectrum is absorbed so rapidly by water molecules. A 6500k CFL, or 10watts of any blue LED grows any type of algae or cyanobacter you want to the capacity of your nutrient levels. 

There are lots of people who have severe nuisance algae problems in salt water tanks running 14-20k halides, and those type of bulbs have virtually zero spectrum beyond yellow. So much for needing 660-670nm LEDs.

When the weather starts getting warmer I'm going to test and see how much wattage in terms of red LEDs it takes for demanding fruiting plants. I've done my own metering tests with metal halide and concluded that LED has about a 2:1 advantage over metal halide in the blue range, but orange-red is still open to debate.


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## Inkidu

Thanks for the reply.

These are some of my first hand observations. 

I have over the last 2 days turned off my 660 nm deep reds, which just 

leaves my ledengin warm whites and an assortment of royal blue and blue 

rebels lighting the filtration setup. Without going into many particulars

an algae scrubber(my filtration setup) is essential an area that is optimized to 

grow algae i.e. the right water flow and light. 

So far decent growth on my screen, which is used as a place for the algae to 

grow. That said I was running 10 watt deep reds and I believe it was just to 

powerful/ to much light. I was getting some patchy growth in some areas. 

The screen is 0 to only a few mm under the water so 

while there is certainly more red absorbed by water than blue because of 

the depth that absorption is negligible. It is important to understand that

an algae scrubber needs to be able to grow a lot of algae to be effective.

So you can remove and regrow as much algae as possible. This is how 

the waste is removed. This also enables a lot of feedings. 

The lights for the algae scrubber are on for most of the day. 

So my intentions with going with colored led and relative to this thread 

is to grow efficiently and quickly plant/algae growth. 

Trying different setups to see 1st hand what works. 

Thanks for any help.

Side note/assumption

As much as I like to experiment with colored led for growth I am leaning 

toward the idea that just getting the newest most efficient led might make 

sense more. The manufactures I would assume are more concerned with 

making the best white (blue) light than any red colored light. 

I have been using warm white led, which do emphasize the red spectrum.


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## blasterman

> The manufactures I would assume are more concerned with making the best white


 
Yep, that's why I decided to punt and start working with the 20watt Satistronics. Neither Cree nor Bridgelux seem interested in state of the art 'blues'. 

I strongly encourage testing, testing and more testing. However, I'm still tellin ya' that a handful of generic 3-watt blue LEDs will grow the most algae at the least energy penalty. I'm also increasingly finding that white light doesn't do much at all.


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## Inkidu

Thanks for the reply.

On the other section of my algae scrubber I have

a 10 watt warm white and 10 watt red led of the type you refer.

I got them off ebay. 

Also on the same 6" by 10" heatsink I have 5 rebel cool whites

and 1 rebel red. I get better growth from the warm white ledengin,

rebel royal blue and blue, and deep red heat sink side. 

That said I have (2) 18 watt meanwell drivers on the first setup mentioned 

and have (1) 60 watt, (1) 30 watt, and (1) 18 watt driver on the later.

Obviously more power. It has been fun testing to see what works and

doesn't but it hasn't been cheap.

I am curious to see how the (8) xp-g warm white and (8) xp-e 470 blues

will do. (waiting for the (10) 680 nm marubeni) backorder

I might also add (8) 660 nm to that new revision. But I will go with

the 5 watt versions this time and spread this revision

over the entire length that currently is covered by the first two

setups I have now. 

I will need to wait for a few more days to get an accurate comparison 

on how well the blue, royal blue, and warm white setup does with out the 

deep reds. 

Thanks for any help.


----------

