# Anyone using LED grow light?



## daniella3d (Aug 30, 2014)

Hi, I am sure this has been asked before but the search result does not give me anything for LED grow light so...

Does anyone here use these LED grow light? how many hours per day? and what is the watt and distance from the plant you are using?

Currently I have a 180W UFO grow light for my Philippinenses and my Sanderianum, about 14" distance, 12 hours per day (hours of light at their natural location in Borneo year around). This past winter I did not have any paph and I used this ligth for my nepenthes and they did extremely well under this light. My mirabilis became all red, produced lots of pitches and did one flower spike. So I was not too afraid to use it for my paphs.

Should I increase the duration to get my plant to flower? for now the foliage is a medium to light shade of green, not dark green. What is your own experience with this type of light?


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## naoki (Aug 30, 2014)

I use several kinds of LEDs, and I place my 90W 5-band UFO (which is actually around 67W consumption) further than 14" (I think around 2' to the top of the leaves). But the beam angles are different from one model to another (mine has really narrow angle, so small coverage). Also the variation in efficiency among models are dramatically different (mine is an older generation which uses so-called 1W diodes, I believe). So it's not easy to say what is the good distance for your model. 

I just went to measure the intensity of my 90W UFO. At 12", mine is giving about 1/4 of the full sun (a bit technical, but the photosynthetically active radiation, PAR, of 550 micromole/m^2/s). If you double the distance, the intensity goes down by 1/4, so at 2', I'm giving about 140 micromole/m^2/s, which is pretty good for Paphs. This is equivalent to 700 foot-candle (fc) of sun light. It seems to be lower than what is recommended, but the recommendation is usually for the peak intensity (i.e. at noon of natural light). With the continuous light of 700 fc, you are giving similar cumulative amount as 1000-1400 fc PEAK light under greenhouse.

Without PAR meter, it is difficult to know the appropriate distance. But if they are growing well without leaf burn, it is probably good. I personally would start from further away, and then gradually make it closer.

How many sqft of area is your 180W covering now? I would guess the height which will cover about 3x3' is probably good for Paphs. I'm assuming that your 180W model is about 120W actual consumption, which can cover about 12 sqft or less (for Paph type light). 10W per sqft. could be a bit low end even for Paph (here I'm talking about the actual watt, and what is advertised with LED is usually NOT the actual energy consumption).

I use 13-14h/day.


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## TyroneGenade (Aug 30, 2014)

Ray, of www.firstrays.com, sells a nice screw in LED that seems to work well. 

Regarding PAR readings you can take a good guess using a Lux meter providing you are using a cool, natural or warm white LED. On average you get about 0.013 PAR/lumen. If you have blackberry or the like, you can download a luxmeter app and get a reasonably measure of the lux. Using the 0.013 conversion factor you can guestimate the PPFD (photosynthetic flux density: microE/m2/2).


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## daniella3d (Aug 30, 2014)

thanks for the info!

I am using a 180 watt 8 bands model based on 3 watt diodes. The lens are 120 degree so they spread wider and less concentrate than a usual 60 degree lens.

I just bought a light meter and should receive it in few weeks but I was wondering if the measurement from these meters is right when measuring such narrow bandwidth of light. It will measure in lux or foot candle, but not in PAR.

Glad to know that your 1 watt based model does well at 2 feet height. Meaning probably I should rise my light to 2 feet instead of the 18" I am using. My terrarium is 3' x 2' and for now only half the LED are working because one of the two controller need to be replaced. I guess once I replace it and all the LED are working I will have to rise the lamp for sure. The foliage is getting lighter not darker.




naoki said:


> I use several kinds of LEDs, and I place my 90W 5-band UFO (which is actually around 67W consumption) further than 14" (I think around 2' to the top of the leaves). But the beam angles are different from one model to another (mine has really narrow angle, so small coverage). Also the variation in efficiency among models are dramatically different (mine is an older generation which uses so-called 1W diodes, I believe). So it's not easy to say what is the good distance for your model.
> 
> I just went to measure the intensity of my 90W UFO. At 12", mine is giving about 1/4 of the full sun (a bit technical, but the photosynthetically active radiation, PAR, of 550 micromole/m^2/s). If you double the distance, the intensity goes down by 1/4, so at 2', I'm giving about 140 micromole/m^2/s, which is pretty good for Paphs. This is equivalent to 700 foot-candle (fc) of sun light. It seems to be lower than what is recommended, but the recommendation is usually for the peak intensity (i.e. at noon of natural light). With the continuous light of 700 fc, you are giving similar cumulative amount as 1000-1400 fc PEAK light under greenhouse.
> 
> ...


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## daniella3d (Aug 30, 2014)

I need to buy another of these lights for my new phrag, so that they have more light in winter. I want a 3w based led light with 8 or 8 bands, not something white. I don't ming a purple light if it's better for the plants.

I have an Iphone, so not sure this application is available but I will check it out. thanks a lot!




TyroneGenade said:


> Rick, of www.firstrays.com, sells a nice screw in LED that seems to work well.
> 
> Regarding PAR readings you can take a good guess using a Lux meter providing you are using a cool, natural or warm white LED. On average you get about 0.013 PAR/lumen. If you have blackberry or the like, you can download a luxmeter app and get a reasonably measure of the lux. Using the 0.013 conversion factor you can guestimate the PPFD (photosynthetic flux density: microE/m2/2).


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## Silvan (Aug 30, 2014)

I have a few of these : http://www.ebay.ca/itm/140W-LED-Gro...?pt=US_Hydroponics&hash=item19e9ff1638&_uhb=1

I call it the fake 240 watts since it's 80 x 3watts led, but depending on the colour it never uses the full 3watts capacity of the led...

I really love it. I keep my plants at a minimum of 3 feet under the fixture and
it's quite enough. I've been playing with length of time and I find that it's
the same as if you would grow under normal fluos (12-15hours).


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## Silvan (Aug 30, 2014)

But it's a real pain for the eyes...


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## Silvan (Aug 30, 2014)

My kovachii 'Jewel' last december before going under Led (Used to be grown 2feet under a fixture of 4x4f. T5HO 6500k) :






same plant picture taken today :







I'm all about results!


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## TyroneGenade (Aug 30, 2014)

Hello,

I agree, those lights look ugly.

If you know the exact band widths of the 8 band lights you can go visit http://www.1023world.net/diy/spectra/ It will give you the uE/m2/s and Lux values for each LED. If you know the number of LEDs and the ratio of the different band widths you can work out an average Lux:uE/m2/s ratio you can use to work out what your uE/m2/s is based on a Lux reading.

If you are getting a quantum meter then you are going to measure in uE/m2/s in any case but the Lux meters are measuring of a spectrum from 400 to 700 nm but it peaks between 500 and 600 nm. The Lux values on the website take into account the relative effectiveness of the lights of 400-500 and 600-700 nm at registering on the lux meter.


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## Silvan (Aug 30, 2014)

Thanks Tyrone, that's a very useful link!

I also have one of these : http://www.ebay.ca/itm/98bulbs-3W-c...LH_DefaultDomain_0&hash=item1e817b3431&_uhb=1

it's less agressive for the eyes. But I've only been growing under this one for about three months so I can't say if my plants likes it or not. If you scroll down on the page it gives you the wavelength and power consumption for each color and
some very interesting infos.


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## Erythrone (Aug 30, 2014)

Silvan, your Kovachii is spiking???


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## Silvan (Aug 30, 2014)

For my seedlings of phragmipediums I use this one :

http://www.ebay.ca/itm/Grow-LED-Lig...?pt=US_Hydroponics&hash=item3a7d1ef81c&_uhb=1

Right now I'm only using half of it's strength. 











nice colour of leaf :





...man, this post is making me realize that I have a lot of plants.. :rollhappy:


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## Silvan (Aug 30, 2014)

Erythrone said:


> Silvan, your Kovachii is spiking???



Yup. Two of my kovachiis are spiking. 'Jewel' and 'Laura x Ana'.
One growing under led in rock wool/diatomite and the second one
under T5HO in a bark mix..


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## daniella3d (Aug 30, 2014)

This light is quite blue, so it will favor the growth but not flowering?

I use to have a reef aquarium and this is the type of LED light to use for corals, a lot of blue.

Why did you choose that one instead of those with more red?

I like the 150 watt light in your link. I might get that one.

I don't really care about the color output, and I don't mind looking at my plants in purple. I want the best for the plants.




Silvan said:


> Thanks Tyrone, that's a very useful link!
> 
> I also have one of these : http://www.ebay.ca/itm/98bulbs-3W-c...LH_DefaultDomain_0&hash=item1e817b3431&_uhb=1
> 
> ...


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## Silvan (Aug 30, 2014)

the shipping cost for the one from the states was (is) verrrry expensive and it doesn't take in account that you'll have to pay for customs (about 25$ CAD).
But it's a good light.

I bought the one for aquarium because it had more blue and white as the leds usually have a lot of reds (3:1) and I wanted to try something with the reverse ratio because I wanted a more luscious foliage  And when I started using led I burned a lot of plants with the ones that had more red in them (and more wattage).
Now that I figured out the distance I don't have that problem anymore.
You can flower some phragmipediums under cool whites (T12/T8). They don't all need intense lights. Under this fixture I have a lindleyanum in bloom, angreacum lemforde. There's also a longifolium, mem. Jack Stoddart, Hanne Popow,
Jerry Lee Fischer and Hanne Popow x Lutz Rollke that are spiking. I think it's more about the quality of light than the intensity when using Led lights.


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## Bjorn (Aug 31, 2014)

Silvan said:


> Yup. Two of my kovachiis are spiking. 'Jewel' and 'Laura x Ana'.
> One growing under led in rock wool/diatomite and the second one
> under T5HO in a bark mix..



I am highly impressed, what about temperatures?


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## naoki (Aug 31, 2014)

That seems to be a really quick recovery of P. kovachii! It looks like a pretty compact clone?

Daniella, if you are a little bit handy, Cree CXA-3070 is a great deal (cheap initial cost, high efficiency, easy to DIY). It uses newer COB (chip-on-board) technology. I'm not sure what you mean by best, but if you mean the most growth (most PAR) per given electricity cost,  Build My LED is pretty high up there (fairly expensive initial cost, though). This paper has tested several LED fixtures, and BML stuff is near the top. I don't know how well CXA-3070 compares to these top-dogs, but from my testing against cheaper ebay COB LEDs, I was pretty impressed.

Silvan's 140W is probably the one made by a big chinese maker, Bysen (I think it's Helios Series). I think a few of diodes (not all) are Cree. It looks like that it has nice homogeneous light spread, and it's looking pretty nice!

With regard to the half-broken UFO, it could be caused by only a few open-circuited diodes (instead of the driver). Since many of diodes are serially connected, if one diode breaks open, quite a few diodes don't light up. I have cheap LED fixtures, which I have to keep replacing the diodes every couple months.

With red vs blue spectrum for flowering vs vegetative growth, it is too much of generalization. It is true for some plants whose flowering is determined by day/night length (photo-periodic plants), there isn't much evidence for red vs blue influencing the flowering of most orchids. I agree with Silvan that orchids will flower under blue-ish light.

The other more general effect of light spectrum is the shape of plants. I personally think that the reef-type LEDs may not be most efficient for orchids (but I may wrong because blue LED is usually more efficient in terms of producing photons per watt than red ones). But it may make the plant to be more compact. This effect seems to be fairly common in plants, but orchids may respond differently (I haven't seen any experiments to test the effect of blue light, cryptochrome-related photomorphogenesis, in orchids). Silvan, do you happen to notice that orchids under the reef light is more compact than the red dominated light?


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## Linus_Cello (Aug 31, 2014)

wow, such blue light... where's the tridacna?


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## daniella3d (Aug 31, 2014)

So where do you buy your led kit? I would not mind building my own kit if it was more affordable that way. What I meant by what's best for the plants is I want the best light spectrum for the plant growth, never mind how it look to my eyes, I don't care about that.

Some people go with the white light because they can't stand the purple color, but it's not as efficient for the plants. I may be wrong but I think my sanderianum might grow faster under a light that provide lots of photosynthesis instead of a light that provide just half of it or so. This plant is such slow growing that I want to do what ever I can to help it get there faster and better. So far my Philippinense are growing like mad under the LED.

As for my light that has half of its light out, it's the controller for sure, because each half is controller by its own controller and I tested it and the half that is out will light up if I exchange the bad controller with the good one. These little controller are 8$ free shipping, so not so bad to repair. I have that led light for a little more than a year.

I am looking forward to hear about what will happen with the plants under the blue light. It works great for corals, never tought about using it for plants but....I know that with a reef aquarium growing under a blue light discourage the algae growth, whereas using a red light can create a real problem with algae but many people still use some red light because they also have marine aquatic plants. Those plants usually grow much better with the red light and not so much with the blue. Just a thought.





naoki said:


> With regard to the half-broken UFO, it could be caused by only a few open-circuited diodes (instead of the driver). Since many of diodes are serially connected, if one diode breaks open, quite a few diodes don't light up. I have cheap LED fixtures, which I have to keep replacing the diodes every couple months.
> 
> With red vs blue spectrum for flowering vs vegetative growth, it is too much of generalization. It is true for some plants whose flowering is determined by day/night length (photo-periodic plants), there isn't much evidence for red vs blue influencing the flowering of most orchids. I agree with Silvan that orchids will flower under blue-ish light.
> 
> The other more general effect of light spectrum is the shape of plants. I personally think that the reef-type LEDs may not be most efficient for orchids (but I may wrong because blue LED is usually more efficient in terms of producing photons per watt than red ones). But it may make the plant to be more compact. This effect seems to be fairly common in plants, but orchids may respond differently (I haven't seen any experiments to test the effect of blue light, cryptochrome-related photomorphogenesis, in orchids). Silvan, do you happen to notice that orchids under the reef light is more compact than the red dominated light?


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## Erythrone (Aug 31, 2014)

Silvan said:


> Yup. Two of my kovachiis are spiking. 'Jewel' and 'Laura x Ana'.
> One growing under led in rock wool/diatomite and the second one
> under T5HO in a bark mix..



I just realize you were writing about PK hybridisation for this reason...
oke:oke: As we say here "Pas vite, la fille"


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## Silvan (Aug 31, 2014)

Bjorn said:


> I am highly impressed, what about temperatures?



I'm also impressed..lol But both my plants are old. They just didn't regress 
this summer. I bought the 'Jewel' in March 2011 from the botanical garden
that was grown from a flask imported in 2006. So this plant is around 8 years old.
I got my 'Laura'x'Ana' around five years ago as a medium seedling. Even if
the flower stem doesn't develop or abort, at least I know that they are mature
enough to flower. 
It's 25 celsius (80F) right now in my basement. Too darn hot!


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## Silvan (Aug 31, 2014)

Erythrone said:


> I just realize you were writing about PK hybridisation for this reason...
> oke:oke: As we say here "Pas vite, la fille"



oke: lol
If I don't find anything to pollinate my kovachiis with, I think that I'll
make a sib.


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## daniella3d (Aug 31, 2014)

The MOntreal botanical garden? how do you buy that from them? I have been often to their store and never saw this type of orchid, last time I went there they did not even had a paph in display in their green house?



Silvan said:


> this summer. I bought the 'Jewel' in March 2011 from the botanical garden
> that was grown from a flask imported in 2006. So this plant is around 8 years old.
> I got my 'Laura'x'Ana' around five years ago as a medium seedling. Even if
> the flower stem doesn't develop or abort, at least I know that they are mature
> ...


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## Silvan (Aug 31, 2014)

Here's a picture of the growth of my Fritz Schomburg that was grown under
my fixture of T5HO and the new one grown under my 140w Led (red). I don't know
if the size is because of the led or that since it had flowered it's getting more
of a normal mature size plant ?












As for the reef light it's still too soon to know. But right now I find my plants to be a bit pale green. But it's a higher wattage system so
it may be because of that...


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## Silvan (Aug 31, 2014)

daniella3d said:


> The MOntreal botanical garden? how do you buy that from them? I have been often to their store and never saw this type of orchid, last time I went there they did not even had a paph in display in their green house?



I got this kovachii because I was a member of the orchidophiles de Montreal (french version of the orchid society). Sometimes they sell orchids during their
show that is held in the month of May (rencontre horticole du JBM). I got my
Saltimbanco and Andean Tears from that show


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## Silvan (Aug 31, 2014)

Another thing that scares me about those Led fixtures is that if one of the diodes burns out how will I be able to change it if I don't know the right color and will I 
have to buy an entire new system in a few years ? I think that I'll have to really
look into Naoki's on making those lights ourselves.. lol


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## Silvan (Aug 31, 2014)

daniella3d said:


> The MOntreal botanical garden? how do you buy that from them? I have been often to their store and never saw this type of orchid, last time I went there they did not even had a paph in display in their green house?



Did you know that you can preorder orchids from sellers for the next show ?


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## daniella3d (Aug 31, 2014)

No, I have no knowledge of this society but I surely want to be a member now and I surely want to attend that show in May. And...I surely want to pre-order some nice ones. How do you pre-order? just become a member?

With my UFO led lamp, so far I replaced one controller that quit, and it was very easy to replace, just unscrew, unplug the old controller and replug the new one. I never had a led go bad so far so not sure how it goes if one fail. I have read from some of these sellers on ebay that they have such system that if one led goes bad then no others are affected.




Silvan said:


> Did you know that you can preorder orchids from sellers for the next show ?


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## Silvan (Aug 31, 2014)

You can't preorder from the botanical garden. 
What I meant was that for the next show like ECOS orchidfête 2014 they usually list the vendors that will be attending this particular show and you can preorder from them. Sam from orchidinnusa won't be attending but you can send him an
email for an updated list of his plants as he's coming to Canada in september. Orchids Limited is coming to Canada in October but it's too late for plants listed in appendix 1. And for phragmipediums, Peruflora ([email protected].net) is also coming in October. You can send them an email to get their curent lists.


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## Silvan (Aug 31, 2014)

the french orchid society is called : Orchidophiles de Montreal : http://orchidophilesmontreal.ca


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## daniella3d (Aug 31, 2014)

Ok thanks for the link, I sent them a message to become a member.

Will get in touch with the people in your other links as well to get what they have available. Are the society meeting interesting? I see it's third wednesday of each month, so I may attend the next one.



Silvan said:


> the french orchid society is called : Orchidophiles de Montreal : http://orchidophilesmontreal.ca


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## daniella3d (Aug 31, 2014)

Ok all done! thank you sooooo much!!! :clap:



Silvan said:


> You can't preorder from the botanical garden.
> What I meant was that for the next show like ECOS orchidfête 2014 they usually list the vendors that will be attending this particular show and you can preorder from them. Sam from orchidinnusa won't be attending but you can send him an
> email for an updated list of his plants as he's coming to Canada in september. Orchids Limited is coming to Canada in October but it's too late for plants listed in appendix 1. And for phragmipediums, Peruflora ([email protected]) is also coming in October. You can send them an email to get their curent lists.


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## Silvan (Aug 31, 2014)

If you are overwhelmed by the quantity of paphs that Sam has, get at least a rothschildianum. I waited way too long to get one. 

The september meeting is the first one of the season, so usually it's the more crowded. It's fun, even when you don't know anyone at first.


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## daniella3d (Aug 31, 2014)

I will go to that meeting if I can. This is the one I would like, it look a lot like the one you posted in your other thread, same color pattern, so beautiful!






Phragmipedium (kovachii x wallisii) from Peruflora
I will try to get it from them.




Silvan said:


> If you are overwhelmed by the quantity of paphs that Sam has, get at least a rothschildianum. I waited way too long to get one.
> 
> The september meeting is the first one of the season, so usually it's the more crowded. It's fun, even when you don't know anyone at first.


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## Silvan (Aug 31, 2014)

I only know two people that were successful flowering the Andean Tears... 
and I'm not one of them, ... But it's still worth the try. Amazing and huge flowers.
Peruflora has it listed for 30-35 dollars (to bloom in two years ...so I guess it means large seedling).


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## daniella3d (Aug 31, 2014)

That's a reasonable price to try it. I would not try it if it cost 300$ but 30 to 35 is not much to lose.

Well, I have not bloom a single paph or phrag yet. I only have one blooming now and I just bought it that way...so first time will be exciting! if it ever happen 



Silvan said:


> I only know two people that were successful flowering the Andean Tears...
> and I'm not one of them, ... But it's still worth the try. Amazing and huge flowers.
> Peruflora has it listed for 30-35 dollars (to bloom in two years ...so I guess it means large seedling).


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## naoki (Sep 1, 2014)

daniella3d said:


> So where do you buy your led kit? I would not mind building my own kit if it was more affordable that way. What I meant by what's best for the plants is I want the best light spectrum for the plant growth, never mind how it look to my eyes, I don't care about that.



There isn't a kit, but the only special components you need are the LED and driver (and possibly thermal adhesive or LED holder). The rest (CPU heatsink, thermal paste, and 5-12V DC wallwart) can be found for cheap or free.

I got my cxa3070 from digi-key (US$40 + $ 3 or so for shipping). I think there is Canadian digikey (or Mouser). Then the driver is a generic ebay driver from China. Here is an example. You can search "50W LED waterproof driver", and find a cheap one (around $10-15). The efficiency of drivers differs a bit, but even the cheap ones are fairly decent (get around 89% AC to DC conversion efficiency).

It is better if you can drill and tap the heatsink to attache the LED, but if it is too much of trouble, iit is really easy to glue them with thermal adhesive. Running at 50W, I can place it about 3' above the plants, and I get about 100-140 micromole/m^2/s (good amount for Paphs). One CXA3070 covers about 2x2' area.

It is a white LED. The white LEDs used to be less efficient than monochromatic ones (you lose light due to the need to use phosphor coating). But due to the large market for white LEDs, the white technology seems to be improving faster than monochromatic LEDs.


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## NYEric (Sep 1, 2014)

Silvan said:


>



Is this what it really looks like?! OMG! No wonder you're smiling! electric Kool-aid!


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## daniella3d (Sep 1, 2014)

Not as much as it look in this photo though, it does have a purple tint. I don't mind it because it's every bit of energy that my plants can actualy use. It's possible to add a regular white light in there to help but it's wasted energy for our own eyes 





NYEric said:


> Is this what it really looks like?! OMG! No wonder you're smiling! electric Kool-aid!


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## TyroneGenade (Sep 1, 2014)

naoki said:


> It is better if you can drill and tap the heatsink to attache the LED, but if it is too much of trouble, iit is really easy to glue them with thermal adhesive.



Great! Thanks. I'm having trouble with my LED strips coming loose (stupid 3M tape) and this looks like the fix I need.


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## ALToronto (Sep 1, 2014)

daniella3d said:


> Not as much as it look in this photo though, it does have a purple tint. I don't mind it because it's every bit of energy that my plants can actualy use. It's possible to add a regular white light in there to help but it's wasted energy for our own eyes



That's not really true. Plants do benefit from a broader spectrum. The UFO lights were developed for large scale cannabis growers, who grow the plants as annuals. They're concerned only with the year's harvest, not the longterm health of each plant. So just like with fertilizers, we cannot imitate the regimes of commercial growers, who need to bring their plants up to blooming size as quickly as possible.

So even though you are likely to see a short-term benefit from the red and blue lights, I wouldn't want to keep them lit exclusively this way for 5 years or longer. My best growing plants are in a south-facing window. My second best growing plants are lit with a combination of 5000K and 3000K 5W LED's.


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## daniella3d (Sep 1, 2014)

Any info on what you are saying? where did you get that? Are you telling me that people cannot grow orchids on the long term with artificial light?

The UFO light I am using has blue and red but also other wave like IR, UV and some green, it's not just blue and red. Also it is supplemental light because my plants are located right beside a ouest facing window so they do get natural sunlight, few hours per day, shaded with a curtain.

So what are you going to do with your plants under LED? how long do you have them growing with LED?



ALToronto said:


> That's not really true. Plants do benefit from a broader spectrum. The UFO lights were developed for large scale cannabis growers, who grow the plants as annuals. They're concerned only with the year's harvest, not the longterm health of each plant. So just like with fertilizers, we cannot imitate the regimes of commercial growers, who need to bring their plants up to blooming size as quickly as possible.
> 
> So even though you are likely to see a short-term benefit from the red and blue lights, I wouldn't want to keep them lit exclusively this way for 5 years or longer. My best growing plants are in a south-facing window. My second best growing plants are lit with a combination of 5000K and 3000K 5W LED's.


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## daniella3d (Sep 1, 2014)

I bought 2 andean tears they had on their list, plus one china dragon. Can't wait 

The Andean Tears are seedlings but at least they are not too expensive to try. The China dragon is BS and 70$.

I will pick them up at the show in October. How does it go when you order for a show, do you pay up front or do you pay when you pick them up at the show?



Silvan said:


> I only know two people that were successful flowering the Andean Tears...
> and I'm not one of them, ... But it's still worth the try. Amazing and huge flowers.
> Peruflora has it listed for 30-35 dollars (to bloom in two years ...so I guess it means large seedling).


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## BLReed (Sep 1, 2014)

You might want to consider these. My understanding is that they replace T5 and T8 in fixtures with an electronic ballast. Not magnetic ballast.

http://www.hortamericas.com/catalog/horticultural-lighting-led-lights/GreenPower-TLED-DRW-18W.html

Here one Link to a YouTube video

http://www.youtube.com/watch?v=L_Ya9wDMdUA

and another

http://www.youtube.com/watch?v=u8-FKHAVsnA


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## daniella3d (Sep 1, 2014)

Strange, they write ''Call for price'' There is no info on how many led there are in their tubes, could be just 1 watt diodes? I see 30 watts or so per tube.

No clue what is the price on those and you still need to have a T5 fixture which I don't have and that can be expensive.

I might just go with the DIY LED kit.



BLReed said:


> You might want to consider these. My understanding is that they replace T5 and T8 in fixtures with an electronic ballast. Not magnetic ballast.
> 
> http://www.hortamericas.com/catalog/horticultural-lighting-led-lights/GreenPower-TLED-DRW-18W.html
> 
> ...


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## Bjorn (Sep 2, 2014)

Its a common misconception that plants do not need green light. They do but do not utilise it to the same degree as the red and blue. That is why they appear green. You might benefit from looking at this site
http://www.heliospectra.com/
and even better to look into this paper
http://www.heliospectra.com/sites/default/files/general/What light do plants need_5.pdf
Heliospectra is a company that specialises into LED Equipment for research, so their equipment is beyond (financial) reach of most of us..


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## daniella3d (Sep 2, 2014)

Interesting paper. But there are some green light in my UFO lamp, and some IR, it's not only 2 bands, one is 8 bands full spectrum and the other is 10 bands full spectrum. It's very much geared for plant photosynthesis, not human benifit, so I don't see why it would have any long term negative impact in the plants.

I keep reading conflicting info about this green spectrum...here is a thread you migth want to look at:

http://www.slippertalk.com/forum/showthread.php?t=31426

http://pcp.oxfordjournals.org/content/43/6/639.long



Bjorn said:


> Its a common misconception that plants do not need green light. They do but do not utilise it to the same degree as the red and blue. That is why they appear green. You might benefit from looking at this site
> http://www.heliospectra.com/
> and even better to look into this paper
> http://www.heliospectra.com/sites/default/files/general/What light do plants need_5.pdf
> Heliospectra is a company that specialises into LED Equipment for research, so their equipment is beyond (financial) reach of most of us..


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## ALToronto (Sep 2, 2014)

daniella3d said:


> Any info on what you are saying? where did you get that? Are you telling me that people cannot grow orchids on the long term with artificial light?
> 
> The UFO light I am using has blue and red but also other wave like IR, UV and some green, it's not just blue and red. Also it is supplemental light because my plants are located right beside a ouest facing window so they do get natural sunlight, few hours per day, shaded with a curtain.
> 
> So what are you going to do with your plants under LED? how long do you have them growing with LED?



Daniella, the LED's I use are broad spectrum white light. 5000K is closest to pure white, 3000K is a warmer white with more red. So the combination of these lights gives a very good approximation of sunlight.

I was talking about the red/blue UFO lights when I said that I wouldn't want to grow plants under them longterm. They're ok as supplementary lights. But now that LED technology has improved so much for broad spectrum white lights, I would not consider the UFOs even for occasional supplementation.


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## Bjorn (Sep 2, 2014)

daniella3d said:


> Interesting paper. But there are some green light in my UFO lamp, and some IR, it's not only 2 bands, one is 8 bands full spectrum and the other is 10 bands full spectrum. It's very much geared for plant photosynthesis, not human benifit, so I don't see why it would have any long term negative impact in the plants.
> 
> I keep reading conflicting info about this green spectrum...here is a thread you migth want to look at:
> 
> ...



It is probably possible to grow without green light, but personally I have always believed that making the conditions as close to nature gives best results. And so far.....the sun is not yet red:evil:
For many species I believe I have good results


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## naoki (Sep 2, 2014)

I think Alla's initial statement is an overstatement (e.g. analogy to fertilizer). If you look at the fluorescent light, many of them (cheaper ones) have really narrow spectra (major 3 peaks because of phosphor emission peaks). Many people have been using it for a long time. It is true that we are still discovering the basic plant physiology. Currently, we know that plants have sensors to detect red/far red, blue, and UV. And it's likely that more "eyes" of plants will be discovered in the future.

There are two aspects about how light quality (spectra) influences plants. First, these light sensors are used to "see" the environmental change, and plants use these cues to change their morphology and life cycle (examples: photomorphogenesis such as etiolation and photoperiodism such as timing of flower, which isn't so relevant to many orchids).

Then the other part is photosynthesis. Plants can grow only with red light (or blue light). Initially red light was used, but then blue light was added to reduce the etiolation. Then other different wavelengths are added, and people are trying to optimize the horticultural light. A part of the goal is the highest photosynthetic reaction per given electric energy, but the other goal is to control the growth pattern (photomorphogenesis part). As Bjorn pointed out, it was recently shown that green light can have significant effect of photosynthetic rate under "strong" light. It is hypothesized that when the cells near the surface is receiving more light than the system can handle, additional green light can penetrate deeper into the lower layers of cells, and drive photosynthesis at the deeper level. It is not known if this is the case for lower light plants like orchids. People are optimizing horticultural light, but I think that it is unlikely that a single spectrum is best for both corns and orchids.

Bjorn, something closer to sun is probably a safe bet, but with artificial light, I think that there might be an electronically more efficient spectra (no data).

With regard to the stomatal control by blue/green light (the older thread), it doesn't mean that the green light will slow down the photosynthesis rate, though (at least, I haven't seen that part of the data). The stomata of Paphs are unique among plants, so there are quite a few interesting studies of Paph stomata.


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## daniella3d (Sep 2, 2014)

Ok but is there a study saying that those bleu and red UFO light are bad long term? what makes you say that it's not good to use them long term? they do have green, IR and a few other bandwidth, and you can even add UV (I did not). Nowaday these lights are not only red and blue, they have come a long way. And they are not 1 watt diodes anylonger, at least the good ones. I use a 180 watt with 3 watt diodes. So maybe the initial only blue and red might not be good long term, but I don't think this apply to the new full spectrum LED.

As for using the 5000k light, is it really better for the plants? I would really like to see the study comparing this and showing the effects long term. Is it aviable?




ALToronto said:


> Daniella, the LED's I use are broad spectrum white light. 5000K is closest to pure white, 3000K is a warmer white with more red. So the combination of these lights gives a very good approximation of sunlight.
> 
> I was talking about the red/blue UFO lights when I said that I wouldn't want to grow plants under them longterm. They're ok as supplementary lights. But now that LED technology has improved so much for broad spectrum white lights, I would not consider the UFOs even for occasional supplementation.


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## Silvan (Sep 2, 2014)

I was wondering what does COB (?chip on board?) means ? 
And is (example) a 100w COB is more "intense" than a regular 100w LED ?


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## naoki (Sep 3, 2014)

Daniella, here is a somewhat related poster: http://cpl.usu.edu/files/publications/poster/pub__2576523.pdf
Even though it is using lettuce, there are several interesting aspects. However, it doesn't talk about the long-term effect, which you are asking about (it's unlikely that red+blue is detrimental/harmful in a long term).

Silvan, yes, COB is "chip-on-board". I don't pretend that I understand why it is better. I have read a couple things, but my understanding is that it can manage the heat better (heat is bad for efficiency). A couple related links:

http://www.digikey.ca/en/articles/t...duce-cost-and-save-energy-in-lighting-designs
http://www.cob-led.com/COB-LED-Advantage-Chip-on-board.html

It is difficult to say 100W COB is more intense than non COB. There are lots of variations in LED efficiency. Higher efficiency of COB is probably true if you compare COB against older generations of non-COB (like so-called 1W or 3W LEDs). However, it may not be the case with the newer non-COB. With non-COB LED, I think Cree XM-L2 has one of the highest efficiency (white LED). It is rated at 10W max. I haven't done the comparison for a while, but if you compare 10x XM-L2 vs 1x CXA3070 (rated at 117W max), I think XM-L2 gives slightly more output for a given energy consumption. However, XM-L2 was at least 2-3x more expensive, I believe.

A brief reminder of the "watt" ratings of LEDs:
When people says 3W LED, it CAN handle up to 3W. But most of the time, we drive them at much lower current (e.g. to consume 2W) for the increased efficiency. This is a part of the reasons I'm running CXA3070 at 50W. To cover 8 sq.ft., I could get 2x CXA3070 at 50W or 1x CXA3070 at 100W (initially cheaper, but you aren't getting as much light as 2x 50W). So it's a balance between long-term vs short-term (initial) cost.

The other reason I like COB for DIY is the ease of assembly. Instead of attaching 10-30 diodes, you can put 1 chip. However, there is a counter-side. COB becomes more of a "point-source" light. This means that the lower leaves can be shadowed by upper leaves. When you have a bigger LED panels like yours, more light can reach to the lower leaves.

Sorry for a long reply, but please keep us updated with how aquarium (bluish) light will do with orchids!


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## naoki (Sep 3, 2014)

I was wrong that XM-L2 is slightly more efficient.

It might be a bit tricky to understand how to use this tool, but this is a interesting tool to compare different Cree LEDs.

http://pct.cree.com/dt/index.html

To get the same efficiency of CXA3070 at 50W, you need to run XM-L2 at very low current, and you need 43 of them to get equivalent amount of light (so $40 of CXA3070 vs $250 of XM-L2). Alternatively if you compare the light output of 1x 50W CXA3070 vs 10x 5W XM-L2, you can get 33% more light from CXA3070.

The tool reports only lumen and not PAR (PPF), so we can't compare white LEDs vs monochromatic LEDs (e.g. red, blue).

So to Silvan's question, yes, COBs (at least high-end) seem to be more intense (most of the time). But not all COBs are created equal. My testing, which I posted here previously, showed that ebay Chinese COBs have much lower efficiency, and not worth getting them.

Then Cree has so many different LEDs, and really confusing. Here is an explanation of different product line (COB is not included):
http://flashlightwiki.com/Cree


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## ALToronto (Sep 4, 2014)

daniella3d said:


> Ok but is there a study saying that those bleu and red UFO light are bad long term? what makes you say that it's not good to use them long term? they do have green, IR and a few other bandwidth, and you can even add UV (I did not). Nowaday these lights are not only red and blue, they have come a long way. And they are not 1 watt diodes anylonger, at least the good ones. I use a 180 watt with 3 watt diodes. So maybe the initial only blue and red might not be good long term, but I don't think this apply to the new full spectrum LED.
> 
> As for using the 5000k light, is it really better for the plants? I would really like to see the study comparing this and showing the effects long term. Is it aviable?



We're on the bleeding edge here with lighting plants that need to stay healthy longterm. Any studies available are for crop plants, which are grown as annuals. Even if someone wanted to fund a study of the longterm effects of artificial lights on perennial decorative plants, there wouldn't be enough data available right now, because the top of the line LED's we're using haven't been around all that long. So we don't even know how well the lights themselves will perform longterm.

We're all running our own little experiments, whether we realize it or not.

Naoki, when I bought my LED's (COBs from China; not Cree but seem to be quite good), I asked for spectral graphs of the light output of each temperature, and there was enough flux across the spectrum to make them fairly broad spectrum, rather than trimodal. Yes, they did have distinct peaks at certain wavelengths, but the peaks were not very sharp. The plants seem to like them - I'm getting very good growth on my Catts, and the anthuriums in the s/h catch basin will have to go soon - they're getting so tall, they're shading the orchids on the lowest part of the wall. And this is since April.

My earlier living wall, lit with Ray's rectangular LED lights (which are much more blue than my 5000/3000 K mix), has great vegetative growth, but no flowers. Maybe it's the lights, maybe it's the fertilizers. Maybe it's not enough light. This one's just over 1 year old.


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## daniella3d (Sep 4, 2014)

So I would be better of going with cool white and neutral white CREE led and build my own kit, rather than buy a 8 bands UFO lamp. I am looking at www.rapidled.com and they have pretty much everything. I just with there was something already build for not so expensive.

They do have full fixtures for growing but they are limited to either cool white or neutral white, not a combinaison of both and they are expensive. Not in my budget. Maybe PAR 38 buld would work, not sure?


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## Silvan (Sep 4, 2014)

really cool website Daniella. They have everything. Even T-Shirts! lol
One very cool product they have is the housing for DIY projects for $70. 
Not having the casing was what stopped me from trying. I'm no electrician. 



naoki said:


> please keep us updated with how aquarium (bluish) light will do with orchids!



I will! Right now I find the leaves of my plants to be a bit too light green. It could be that the days are too long, the wattage is too high or that in overall
my plants are starting to be fed up with summer temps. But they are growing. I have to add that I mostly grow phragmipedium under this particular fixture.
I might add some paphs in the near future. But my paphs are really doing great under the 140w. LED fixture. So I might have to buy new plants to try it out..lol

Doing a bit of research I found the disposition of the colors on my 140w system. I really have to print that page.. 
http://www.aliexpress.com/store/pro...amp-Free-Drop-Shipping/224261_1696100481.html

Like Naoki said. The Cree led seems to only be in the center on the module :
http://www.aliexpress.com/item/Heli...pcs-High-Power-Led-Plant-Grow/1793675362.html


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## daniella3d (Sep 4, 2014)

Yes cool site, mostly oriented to reef aquarium, that's how to got to know it, but they do have led for plants as well and the case can be used for plants as well.

I am thinking maybe mixing some warm and cool white and put them on their oxyn case. Sounds like fun project to do with 5 w led.




Silvan said:


> really cool website Daniella. They have everything. Even T-Shirts! lol
> One very cool product they have is the housing for DIY projects for $70.
> Not having the casing was what stopped me from trying. I'm no electrician.
> 
> ...


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## naoki (Sep 4, 2014)

Alla, it's great to hear your plants are getting good growth! I was talking about florescent light which has sharp emission peaks. You are correct, the white LEDs have wider spectra with 2 major peaks (unless it is RGB style white LED). The white LED is basically blue LED, and blue lights excite the phosphor coating to create green and red light (so it looks white).

Daniella, I've never bought from them, but RapidLED could be convenient because they have lots of stuff. But the price is usually quite a bit higher. Are you talking about Bloom Onyx (the prebuilt one)? It looks interesting. After looking the spectra of different color temp LEDs, warmer one seems to match better with photosynthesis (warm white, 2700-3000K). That's what I usually use. But some grow light company uses 4000K. In theory, you need to have more phosphor for warmer color, so number of photons could be lower in warm white (due to some loss from phosphor). However, if you look at the efficiency of photosynthesis (called action spectrum), red light is more efficient than blue light. So it is difficult to say which one (warm vs cool white) is better.

When I measured PAR of chinese 100W LEDs, cool white and warm white had similar PAR (I don't have the number at this moment). So the loss due to phosphor is probably not big, and warm white with more red could be a bit more efficient.

Similarly, you don't want to use higher CRI white LEDs (thick coating and reduced overall output).

Silvan, but the page said the other diodes are Bridgelux (they make good LEDs). I didn't know Bysen-type grow light was using Bridelux for the other diodes.


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## Ray (Sep 5, 2014)

Naoki - when I was developing the chip mix for my 13W lamps, I compared spectra of warm and cold white chips - the "warm" ones did not have "more" red, they had less blue.


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## daniella3d (Sep 5, 2014)

Interesting. So should we go with the cool white since it could be more complete? with the same amount of red but more blue, can we assume it is better and more complete lighting for the plants? And was it the same bandwidth of red?



Ray said:


> Naoki - when I was developing the chip mix for my 13W lamps, I compared spectra of warm and cold white chips - the "warm" ones did not have "more" red, they had less blue.


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## ALToronto (Sep 5, 2014)

I guess different manufacturers have different spectral profiles. My warm white LED's definitely have much greater flux density above 600 nm than the cooler white diodes. All are Bridgelux. Naoki, have you done any comparison to Cree?

When I bought my lights, I also ordered a few 1W red (660 nm) LED's. I was planning to place them among the white ones, just 2 or 4 among 14, but haven't done so yet. The driver for white LED's is at full capacity with the 70W total power, so would I need another driver to add just the 2 or 4 extra watts? The 14 LED's are wired in series pairs, seven parallel branches to match the voltage and current output of the driver.


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## naoki (Sep 5, 2014)

Ray, you are right, that is a more accurate way. But doesn't warm white usually have a wider red peak, so if you compare the cumulative (not the peak height) amount of light in red region, warm white can have more red light? Lots of spectra plots for LEDs are relative to the peak intensity, so it's difficult to make the direct comparison. I think some people has compared theoretical PAR from the spec sheets.

But it sounded too tedious to do the calculation, so I just measured. People say that phosphor technology has been changing quite a bit. So we might not be able to say which one has more PAR in GENERAL. So it would be interesting to see if you can compare PAR of cool vs warm white of yours (I think you got the meter). My comparison of ebay COB didn't show much difference (I was expecting warm white to have less PAR for the reason you mentioned), but it is possible that my meter needs calibration (it has been shown that the spectral sensitivity of Li-Cor sensor, which I have, can shift with age). If they give similar amount of PAR, I would go with warm white. But the difference is pretty small, so either one works in practice.

Daniella, if it is exactly same amount of red, and CW has more blue, yes, I would say that CW is better (in terms of photosynthesis).

Alla, I don't have any Bridglux. Vero series (their COB) is supposed to be pretty good (slightly less efficient than Cree CXA). I don't know well about the complex wiring (and you know better about it), and I thought that most of people use only serial circuit. With the parallel circuit like yours, if a couple diodes go open, doesn't it cause overdriving the rest and fry them? Also, I've heard "matching" diodes could be tricky for the parallel circuit (i.e. some branches get more current than other branches).


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## naoki (Sep 6, 2014)

Just for number geeks: here are the numbers comparing the 100W ebay Chinese COB Warm White (WW) vs Cool White (CW). I drove them with the same 50W ebay constant current driver (1.5A, YM-361500A, waterproof), and measurements were taken at 1'. No reflector was used. The setup was explained here previously.


```
fc1 fc2  PPFD W    PPFD/W
WW 730 1120  180 46   3.9
CW 630 1293  180 45.4 4.0
```

Explanation of columns

fc1: foot-candle measured by Gossen Ultra-Pro calibrated recently.
fc2: foot-candle measured by Dr.Meter LX1330B, which is recently bought.
PPFD: micro-mole/m^2/s, Photosynthetic Photon Flux Density (more relevant for plants than fc), measured with old Li-Cor which probably needs calibration.
W: consumed Wattage by LED (includes loss due to AC-DC conversion of the driver, efficiency of this driver was 89-90%, but exclude the energy used by the CPU fan)

A couple observations:

CW is slightly more efficient than WW by 2.6% (4/3.9=1.026). But once you incorporate the fact that red light is slightly more efficient for photosynthesis than blue light, WW should be giving slightly more energy (Yield Photon Flux Density; YPFD).

But overall, the difference is minimal. But I just tested one unit of each, and the response could be different for other brands and technology.

Gossen is a slightly older, high-end meter for photography/filming. The spectral response of this meter is slightly shifted (more red sensitivity), and it seem to deviate from the CIE luminosity function. Well, most of the affordable light meters deviates quite a bit from the ideal response function. So this is just an illustration of some limitation of consumer-level light meters.


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## daniella3d (Sep 6, 2014)

Hard to get the right idea from comparing these meters though, since your older meter gives a higher value for the WW and it is the opposite with the new meter. I have the meter LX-1330B and I just received it but it's defective, does not turn OFF and the power button put the value in LUX when pressed instead of powering off or on. To turn it OFF I have to remove the battery! and I have to press the lux button many times to have it switched and staying on FC. They seem to be very very cheaply made, so is it possible that your older meter gives a more accurate reading? 



naoki said:


> Just for number geeks: here are the numbers comparing the 100W ebay Chinese COB Warm White (WW) vs Cool White (CW). I drove them with the same 50W ebay constant current driver (1.5A, YM-361500A, waterproof), and measurements were taken at 1'. No reflector was used. The setup was explained here previously.
> 
> 
> ```
> ...


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## naoki (Sep 6, 2014)

Sorry that your LX-1330B had issues. Hopefully, they sent you a replacement. The sensitivity spectrum listed in the user manual seems to be pretty good, but I don't know if the response is real or not. I don't have a reference lux meter to compare them against. But fc is just for human eyes, and isn't as important as PPFD for plants. This is especially true if you are talking about artificial lighting.


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## Silvan (Sep 10, 2014)

This is getting so complex..lol But I'm the type of person who needs to do and see for myself to fully understand..  
Aren't you a bit afraid of short circuit when doing the wiring? Looking at some DIY 
I've noticed that you even have to install the power plug. That kinda scares me
a lot...
Anyway, I'm writing 'cause I was at my hydro store last week-end and they had a super nice Led fixture using the new white lights technology. The seller told me
it was very expensive and I didn't ask how much because anyway it was 390watts
and I would need to put it at least 6feet above the foliage and I don't have that kinda height. But there was something off about it and I couldn't put my finger on what it was until I made some research on the net... it uses a passive cooling system. It doesn't have fans! 
Wouldn't the diodes overheat and burn very fast ? Just wanted your opinion on that.
Here's a link of the product http://www.ledsource.com/wp-content/uploads/2013/10/LightingScienceGroup_VividGroLEDGrowLight.pdf 
and you can find some additional info on the supplier website https://www.lsgc.com/products/fixtures/vgrohb/


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## NYEric (Sep 10, 2014)

Lighting nerds! oke:


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## TyroneGenade (Sep 10, 2014)

Get the warm white. I was chatting with a plant physiologist a while back and he said the plants grow best under the warm white LEDs.

With the CW and WW LEDs the blue peak doesn't shift or change in intensity. The yellow peak of the CW simply shifts towards the red.

Plant action spectrums indicate that it is red light that terrestrial plants want. You may have seen the Elodea/Anacharis action spectrum up on webpages but that spectrum is not typical of terrestrial plants. 

(Just in case, if anyone has a reference for that Elodea spectrum I would love to know it... I have traced as far back as a textbook that used the image unreferenced and the publisher had no idea where the spectra came from.)


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## naoki (Sep 10, 2014)

Silvan said:


> This is getting so complex..lol But I'm the type of person who needs to do and see for myself to fully understand..
> Aren't you a bit afraid of short circuit when doing the wiring? Looking at some DIY
> I've noticed that you even have to install the power plug. That kinda scares me
> a lot...



Silvan, I don't think short circuit is an issue. When wiring, you shouldn't have anything plugged-in! oke:

I use solder, then liquid tape and rubber self-sealing tape. The rubber style tape is much better than the vinyl electrical tape. I used something similar for repairing wiring harness in the engine compartment (of an old car) about 20 years ago, and it hasn't failed.

If you are worried about the LED terminal is exposed (the place where you attach + and - wires to the LED), you can paint it with the liquid tape. Then nothing is exposed to cause short circuit.

The LSG LED fixture you saw is one of the most efficient models according to this test. The test confirmed that the claimed output is true. You get 1.64 micromoles/J (larger number means more photosynthetically relevant light produced for a given amount of electrical energy consumption), the efficiency of fluorescent light is 0.84 micormoles/J, and the top HPS is around 1.7 micromoles/J. The article says the price is around $1200.

But you are right, it might be a bit too much for our purpose. It is better to have more fixtures with less power (so you can get more even light, and more illumination to the lower leaves).

Passive cooling is nice because it doesn't make noise. But it is much more expensive since you need huge heatsinks and you need to use lower current (meaning you need lots of LEDs). I think if it is well designed, it shouldn't burn out.

One disadvantage of active cooling is that, fans can break down, and LEDs can overheat. Some of them may have overheating protection, but mine doesn't. The other issue with active cooling is that it may be more difficult to get water proof certificate (i.e. in a large commercial greenhouse, they may require these certificate).

Some people use CXA3070 with passive cooling. But it is too expensive for me. 

Tyrone, if you are looking for the action spectra of photosynthesis for land plants (I don't know where Elodea figure is from), you can check

Inada, K. 1976. Action spectra for photosynthesis in higher plants. Plant & Cell Physiology 17: 355-365

McCree, K. J. 1971/1972. The action spectrum, absorptance and quantum yield of photosynthesis in crop plants. Agricultural Meteorology, 9:191-216

I think you are in an academic institution, so you can get them there. But if you can't get them, you can email me.

Some basic textbooks seem to have a bit sketchy figure about the action spectra (or confused it with absorption spectra).


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## daniella3d (Sep 10, 2014)

Would it not be better to mix both? Like 3 WW for one CW? to get some blue as well. I have read that without the blue the red will make the plant elongated?



TyroneGenade said:


> Get the warm white. I was chatting with a plant physiologist a while back and he said the plants grow best under the warm white LEDs.
> 
> With the CW and WW LEDs the blue peak doesn't shift or change in intensity. The yellow peak of the CW simply shifts towards the red.
> 
> ...


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## TyroneGenade (Sep 11, 2014)

Hello,

See below:




from http://www.digikey.com/en/articles/...ining-the-color-characteristics-of-white-leds

This is pretty typical. As you move from CW to WW the red peak shifts and grows. There is some expense of the blue light but this isn't very consequential. Plants need some 430 nm light to stimulate growth but this effect isn't cumulative. You only need to add enough and the plant will grow. A friend bought some cheap CW LEDs that didn't have a peak close to 430 nm at all... The plants stayed green but never grew. We took a look at plant growing lamps and figured on a 1:9 ratio of blue to red being the minimum so he fitted enough 430 nm LEDs to meet this criteria and all of a sudden the plants started to grow.

You only need a little violet/blue light and the WW seem to provide it.

My only concern is the we grow shade plants and they may be adapted to more blue light than full-sun plants. Blue transmit well through the forest canopy compared to red... I refer you to this thread: http://www.slippertalk.com/forum/showthread.php?t=32896&highlight=Fluora

The spectrum of the Fluora is interesting as it has a lot of Blue and Red light.




Here is a daylight:




Cool white:




Warm white:





All have the 430-440 nm peak and then varying amount of red. The violet light is needed to stimulate the opening of stomata.

Sadly, I was hoping someone would know where the Elodea action spectrum came from... Oh well.


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