Maybe I'm confused

[Nexogen]

Thank you very much for your cooperation.
Apparently even though this topic (light) I just stressing me, I thought that maybe there are others who want to use the light source in optimal conditions, some may just do it and clarify many unknowns.

[Nexogen]

When using the LED light source I kind cleared the spectrum - Light Absorption for Photosynthesis
The thing is the rate of photosynthesis as a function of wavelength is not too clear (at least for me) when using fluorescent light [when I look in the date book (spectral distribution graphics)]. I am puzzled why only uses 6500K instead of a combination, for example: 6400K and 2700K.
See Spectral Power Distribution in Philips data sheet that seems more efficient. http://www.lumitronlighting.com/lamp...Super%2080.pdf

[ula]

Originally Posted by Nexogen

When using the LED light source I kind cleared the spectrum - Light Absorption for Photosynthesis
The thing is the rate of photosynthesis as a function of wavelength is not too clear (at least for me) when using fluorescent light [when I look in the date book (spectral distribution graphics)]. I am puzzled why only uses 6500K instead of a combination, for example: 6400K and 2700K.
See Spectral Power Distribution in Philips data sheet that seems more efficient. http://www.lumitronlighting.com/lamp...Super%2080.pdf

Hi, I'm not exactly sure what you're getting at, but here's a link comparing LED and fluorescent lighting emissions spectra with a table listing benefits (or lack of) of wavelength bands for plant growth.

Greenhouse, Urban Farming & Horticultural Lighting | Gusco

Of course, this web page is an advertisement, but it seems to me that LEDs give the plants the best action right where they want it . From your specs attached, the fluorescents do seem to miss a lot in the 400s blue side of the VIS spectrum. Sorry if I'm sounding stupid...
Interesting thread btw.

[Nexogen]

Originally Posted by ula

Hi, I'm not exactly sure what you're getting at, but here's a link comparing LED and fluorescent lighting emissions spectra with a table listing benefits (or lack of) of wavelength bands for plant growth.

Greenhouse, Urban Farming & Horticultural Lighting | Gusco

Of course, this web page is an advertisement, but it seems to me that LEDs give the plants the best action right where they want it . From your specs attached, the fluorescents do seem to miss a lot in the 400s blue side of the VIS spectrum. Sorry if I'm sounding stupid...
Interesting thread btw.

My intention was just to open minds.

[naoki]

Originally Posted by Nexogen

When using the LED light source I kind cleared the spectrum - Light Absorption for Photosynthesis
The thing is the rate of photosynthesis as a function of wavelength is not too clear (at least for me) when using fluorescent light [when I look in the date book (spectral distribution graphics)]. I am puzzled why only uses 6500K instead of a combination, for example: 6400K and 2700K.
See Spectral Power Distribution in Philips data sheet that seems more efficient. http://www.lumitronlighting.com/lamp...Super%2080.pdf

Note that light absorption by Chlorophyll is just a part of the story. If you look at the action spectrum of photosynthesis, it is quite different. The details of the web page is a bit different from what has been published from crop plants. I wonder if it is using some aquatic plants or something.

With the Philips data, you should be aware that the Y-axes of the emission spectra are in microW. Each photon of blue light have more energy than a photon of red light. So if you convert the figure to number of photon flux, the bluer peaks should be lower. Plants cares about the number of photons (not energy).

In florescent light, there are several peaks corresponding to different phosphors. The main differences between different K is the proportion of the different phosphors. So the location of the peaks don't change much, but the relative height of the peaks changes with different K.

There are some spreadsheets which contain the calculated PAR for different florescent bulbs (and some LEDs), which is created by planted aquarium people. They also made calculation which considers the photosynthetic action spectrum (i.e. red photons are more valued, and this is called yield photon flux, YPF). But they used aquatic plant curve, so it YPF is quite different for land plants. Sorry, this is probably a bit too technical, but if you are interested in the spreadsheet, send me a PM with your email address.

[Nexogen]

Anyway I do not use previously exposed solution (I exposed this version just to see the fog is in the field), I want to build my own LED light curve below. What I do not know if I will succeed and everything depends on the quality of LED used, yet wait my order.
PS. It is the first light that will make a to z, perhaps the second one will make it cool (given the feedback came from plants)...

[naoki]

The curve you attached is a more standard crop PS action spectrum. Are you trying to use bunch of monochromatic LEDs to make the emission spectrum similar to this? If so, you are probably misunderstanding the meaning of this curve. A simple way to make the action spectrum is to shine the leaves with light with a particular wave length (monochromatic) and measure the photo synthetic rate. The curve doesn't mean that the light with this spectrum is the optimum. The optimum is at the peak of the curve (red) if you are using monochromatic light. But due to the effect of light on photomorphogenesis part, using purely red light isn't so great in many plants.

Also, relatively recent studies have shown that combinations of different wave lengths can results in better PS than predicted by the curve. For example, in the high light condition, addition of green light improves the overall PS output (more than expected from the green light alone). This is not same as Emerson effect, which states that 670nm + 700nm results in a better PS rate than each wave length separately.

[Nexogen]

I ordered:
4 X Epileds chip 50W 45mil full spectrum 7 band led grow light for growth and bloom,
30W COB LED 29V - 34V 2700LM, 5 X Warm White (3000-3500K), 5 X Pure White (6000-6500K),
8 X 5w Epileds 620nm 630nm Red,
8 X 5w Epileds 660nm 670nm Red,
16 X 5w Epileds Blue 455nm 460nm 470nm,
I hope I can do some combinations, unfortunately I do not have spectrometer.

[Nexogen]

I need to use a spectrometer not want to buy, looking to rent but if not I will have no choice.

Of course I will not be able to realize a theoretical curve identical to the one I want to be somewhat close, I want to get a "domestic" light...