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Hello

Many say that the lamps with LED blue and red are the best, ask them if they can explain why supporters larger homes lighting are integrating other colors including white, which is the color that seems to not work for you?

It seems to me that the theory is only partly true, as is often the case there is no better or worse, because our knowledge is not complete.

the my thirst for knowledge is infinite :)

Prompt

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Hello everyone, sorry for my english :) I open this topic to share my experiments with LEDs. I made a long study of white LEDs, I discovered that their light is better than the common fluorescent la

blue and red are a hoax to spend lots of money to people, plants need to grow well many more colors, blue and red are the basic colors only for chlorophyll type A. The sun radiates light is color whi

I have been reading this thread with some interest as I have used LED's for a few years now. The Technology is moving quite rapidly and is difficult to keep up but is certainly improving. I currentl

The following are my creations, the 100-watt ceiling led, this is a very powerful ceiling, suitable for one square meter terrariums.

up view with components and electric wiring

gallery_8021_663_24993.jpg

down view whith led lens

gallery_8021_663_128400.jpg

All the discussion about wavelengths has distracted from one thing and that is the design of your panel, which looks very impressive :thumbsup:

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Hello Dicon,

With regard to the lumen in fact you're right, you can not use the lumens for plants. As regards the efficiency meant that overall, in the white LED wavelengths are varied and summing these lengths theoretically the efficiency as well for plants, increases.Suming the wavelengths is not a benefit surely?as it is firstly a dilution of the best or desired wavelength that is being added back together, (sounds ok) but as the "off target" wavelengths are of Zero use to the chlorophyll they lose any benefit and cannot be added back so are a drop in efficiency.

The plants grow quite well even if they do not receive the peaks of chlorophyll, the fact is demonstrated by those who cultivate with MH and HPS lamps, the majority of these specialized lamps, have peaks on the yellow-orange and yet at the time are the most spread in the workplace. The tubular fluorescent lamps and cfl, are efficient only on the blue band of red is close to zero and the highest peak is green. I think this means that plants have receptors that convert many other colors outside of the peak of chlorophyll.

In monochromatic LEDs but also in white is used for testing a specific costant current, it is evident that the variation of the current may lead to a shift of the emission peak. I also remember that more power equals more power dissipated into heat.As each emitter requires a different voltage, running at constant current is essential, this means that in a properly constructed lamp, th use of say 100 x 3watt chips run correctly (to ensure long life) consumes somewhat les than 300watts.

I do not know if you've had time to read the interesting test lik: http://streetlightin...PIE6337-17.pdf.

Previously not think I explained myself.

I state that I'm talking about self-made lamps, what I meant is that the manufacturers of LEDs, indicate a peak at a certain current, the link shows that the peak can be postponed according to the input current, this means that if an LED 350ma to have a peak at 660 nm, feeding it to 700ma peak could slip up to 10 nm. Then a led grow from 660 to 670nm can pass going well beyond the peak of the Clorophilla.

Also in the link, it shows how the white LED is the most efficient LEDs with PWM current, and still is more efficient in the red with no constant current pwm.

Not use a lux meter but a spectrum analyzer.

Prompt

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I state that I'm talking about self-made lamps, what I meant is that the manufacturers of LEDs, indicate a peak at a certain current, the link shows that the peak can be postponed according to the input current, this means that if an LED 350ma to have a peak at 630 nm, feeding it to 700ma peak could slip up to 10 nm. Then a led grow from 630 to 640nm can pass going well beyond the peak of the Clorophilla.

The peak for chlorophyll a is somewhere near 660nm, that's why commercial grow lights contain this wavelength.

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The peak for chlorophyll a is somewhere near 660nm, that's why commercial grow lights contain this wavelength.

Yes what you say is right and it is known to all, unfortunately I can not explain.

My reference was not to light commercial, however you should always see if their characteristics correspond to the truth.

I wanted to raise the point, especially on home-made lamps. If the LEDs are driven outside of the typical characteristics, the values may vary, ​​including the wavelength , for example an LED declared at 630nm at 300ma, if supplied at 700ma the wavelength may vary 640nm and exit out of the peak of Clorophilla.

Prompt

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there are some great facts coming out of this discussion, really interesting..

those Philips lights look useful as pre-made, anyone tried them? The bulb-style looks convenient.

Cannot find any information on what the 3 different blends of LED colours are supposed to favour plants-wise, anyone know?

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those Philips lights look useful as pre-made, anyone tried them? The bulb-style looks convenient.

Cannot find any information on what the 3 different blends of LED colours are supposed to favour plants-wise, anyone know?

I have the Philips Greenpower LED Flowering Lamp Deep Red/White/Far Red. I've not really had it long enough to say how well it performs, but the Cephalotus I had under it took on good colouration on juvenile pitchers. I'm currently reorganising stuff, so it's not in use right now.

You might find this interesting: The Effect of Red and Far Red Light on Flowering

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This article describes how to couple the IR (far-red) to a white light.

As you can see we still have to find out a lot in the plant world, and more!

http://ag.arizona.ed...se Lighting.pdf

Karl had already mentioned these wavelengths.

These LEDs will be my next investigation.

Prompt

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  • 2 weeks later...

Hi everyone,

I won't enter into much details since there was enough discussion, but, as a former researcher in light perception in plants, I can confirm that the peaks of absorption of the chlorophyll are of course important since planta will take most of their energy to grow at these wavelengths (even though the other wavelengths, despite being less effective, will also provide some energy). However, what is important is that other photoreceptors (cryptochromes, phytochromes, etc) are activated by other wavelengths. These photoreceptors do not transform light into energy for the plant but rather provide the plant with signals about its situation (season, shaded area or in direct sun, etc). The plant uses these signals to "decide" if it should grow quickly or not, if it should accumulate pigments to protects it against damages caused by direct sun light, etc.

The tricky thing is the following: every plant is different. In the lab, people are mostly using "model plants", like Arabidopsis thaliana. And you have to know that the published PAR spectra are mostly the ones of these models plants.

As you can imagine, carnivorous plants are quite special! I did not see the action spectrum of Heliamphoras, for example, but I am quite sure that it differs greatly from the one of Arabidopsis, based on where these plants live.

My main message is: don't count too much on the theory about photosynthesis!

We should try and learn from the experience of others, depending on each main type of plant.

Personally, I'm using this light for my lowland terrarium:

http://www.gothamhyd...w-light-ho.html

It looks mainly white, so no disco-type ambiance, but it has some other specific wavelenghts. I'm quite happy about the results, except that it's quite noisy! Like for most of the commercial LEDs, fans are pretty powerful, which is great for getting rid of the heat inside the lamp, but a bit annoying in my living room...

Here is my Heliamphora cilita, about 60cm from the lamp (picture was taken only with sun light, not the LED). It also receives some indirect sun light. This plant may not be completely red, but enough to say that it receives enough light to grow correctly.

heliam10.jpg

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Hello Vincent, are in tune with your reasoning.

Considers that the warm white LED, used in my custom ceiling, covers by only three lengths for your lamp Red: 630, 660nm, 730nm.

That said, I'm happy with my ceiling, currently below are Nepenthes Highland, some sundew, and seedling of N. Ampullaria born in September, for the moment everything is going as it should.

I just had to adjust the brightness down, I was left with 11,000 lux to 9000 lux now. With the latest control my ceiling light consumes only 68Watt ! In addition emits white light that does not hurt the eyes, and has no noisy fans :)

In future I experimentation by adding LED 730nm, reading many experiments would seem that they have a great effectiveness if used in combination with the other wavelengths. It seems that the phytochrome has an importance in plants that should not be underestimated.

View artcle:

http://www.hort.vt.edu/ghvegetables/documents/GH%20Lighting/High-Powered_LED_Cultivation_Study_2005.pdf

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In future I experimentation by adding LED 730nm, reading many experiments would seem that they have a great effectiveness if used in combination with the other wavelengths. It seems that the phytochrome has an importance in plants that should not be underestimated.

730nm is far red. I have a Philips grow light, which contains white, red and far red, which I am currently experimenting with.

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I have a number of seed grown Nepenthes whch have spent their entire lives under LED, including germination and which are now reaching maturity. My feeling is that most of the benefit is from reduced losses compared with normal lights, e.g. reflectors, light spread, and so on. I'm much less convinced that dfferent color lights, beyond red/blue make much, if any, difference.

On balance, i suspect that the efficiency advantages of selecting different colors are quite small compared to simply using white LEDs which themselves offer a big advantage over flourescents or even HPS, and with the added bonus that your room doesn't look like a disco.

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[...] and with the added bonus that your room doesn't look like a disco.

That is one of the reasons I like the Philips flowering bulb, as whilst is still has the enhanced reds and far red, the white is still quite dominant, as well as providing some light in the blue wavelength, so things look quite natural under it.

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hello mobile, what plants you put in the light philips?

I could not find the graphic spectrograph for your lamp. You have the characteristics of the emission spectrum?

730nm is in fact equivalent to the FAR RED, better still 735nm, that corresponds to the maximum absorption peak of the phitocromo.

Prompt

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hello mobile, what plants you put in the light philips?

Currently, Cephalotus.

I could not find the graphic spectrograph for your lamp. You have the characteristics of the emission spectrum?

730nm is in fact equivalent to the FAR RED, better still 735nm, that corresponds to the maximum absorption peak of the phitocromo.

I can't find it either, but looking at one of their other grow lights, they appear to use far red leds with a wavelength of 725 (min), 740 (nom), 750 (max) nm.

Source: http://www.ecat.ligh...29000464503_eu/

Deep red is 650 (min), 660 (nom), 670 (max) nm.

Source: http://www.ecat.lighting.philips.com/l/oem/led-systems/led-horticulture/greenpower-led/929000464303_eu/

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  • 7 months later...

Dear electronic experts,

I am planning to build something like prompt's ceiling for a new terrarium. However, I am struggling to find LEDs that are not too expensive. The ones I've found on internet are about 8 euros / 2W LED. Which means that to reach 100 W (my goal), it costs 400 euros without lenses, power supply, etc!

I think I'm far from the 200 euros prompt said he paid... :-(

Any links to share to find something cheaper?

Vincent

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However, what is important is that other photoreceptors (cryptochromes, phytochromes, etc) are activated by other wavelengths.
I did not see the action spectrum of Heliamphoras, for example, but I am quite sure that it differs greatly from the one of Arabidopsis

I can only agree! So my question is:

why not use a continuous emitting lamp, that has all the wavelenghts that we know and we dont know are needed?

And that is more efficient than any LED I have seen so far (over 100 lm/Watt)

And provides wonderful light, instead of these strange light colours that even the "balanced" LED setups provide?

And is cheaper to buy?

I still wonder at this LED hype - while e.g. ceramic MH lamps aren't even recognised by most people.

Did I miss something in LED development?

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Hi Martin,

Actually, regarding the costs, I've made calculation (including cost of lamp but also cost of current) and it's cheaper in the long term for me with the LED.

The LED are more efficient than normal lamp in term of light / amount of current. So more ecological, which is important for me.

The LED lamp I use contains colors, but also white. Overall, it looks quite normal. No disco-type!

Cheers

Vincent

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Actually, regarding the costs, I've made calculation (including cost of lamp but also cost of current) and it's cheaper in the long term for me with the LED.

The LED are more efficient than normal lamp in term of light / amount of current. So more ecological, which is important for me.

What is the efficiency value of your LED lamps?

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