Discussion on the aptness of the light sources used in PFC


I have just got some funds from my institute and shall soon start working upon constructing a PFC.

Being an optoelectronics enthusiast who hails from an agricultural background, I have done some share of reading of literature on PAR, and, because of the same, I have been wondering about the aptness of the light sources which have been deployed in the PFC.

Grow LEDs are very variable in their nature and can be based in vitro analysis of components, rather than in vivo.

Most of my readings have come from this thread: https://www.reddit.com/r/HandsOnComplexity/comments/17nxhd/sags_plant_lighting_guide_linked_together/

I really recommend everyone to go through it. The insights offered are amazing.

In a gist, I have been thinking whether the LEDs deployed in the PFC are apt or not. If not, then I reckon we can come up with a basic composition of what LED sources should be used by an exhaustive study of the available literature on PAR, and, also, we can argue that, perhaps, specific LED arrays can be devised, than the available grow LEDs, with the arrays being constructed based upon the relevant photometric calculations, to have the precise amount of required energy from different wavelengths.

Since I have just started this thought-venture, so please guide me if I am talking gibberish :stuck_out_tongue


What are your thoughts on COB LED’s vs the traditional red/blue diodes? I would encourage you to look through the links I provide on this thread as well. I’d be very interested to hear your feedback!

How much have you looked into UV/far red effects?

Here’s a person working to develop a light for the V2 as well.

@andy has looked into this a bit as well I believe.

Edit: Just got into that resource you posted, INCREDIBLE. Thanks!


Hi, @Webb.Peter !

Thanks for the reply.
I have been trying to open the technical sheets in the links you have provided on the mentioned thread, however it gives me a “404 error.”

Will it be possible for you to provide me with the spectral composition of the COB LED? That will really help me deal with certain apprehensions about those LEDs.

Also, about the Red/Blue diodes, I do reckon that, perhaps, these could suffice our sought purpose in a better manner. My rationale is that diodes allow for control over the spectral composition of the illumination, because there’s a plethora of LEDs available, and, depending on the need, we can choose our LEDs. I have mentioned you in another comment on @Poitrast 's thread. That reply and this reply should, perhaps, explain what I’m trying to strive for.


I think I fixed the error, keep in mind this was nearly two years ago now, there is a newer bulb by CREE that is better.

I’m using 3500k, here is the datasheet with SPD

I have had the same thoughts as you regarding diodes. My conclusion though is that for research purposes the diodes do make sense in order to create recipes. From an operations point of view though, I think COBs will end up making way more sense for commercial farms. LED capital costs are a major barrier to entry for most people. Diode LEDs are almost always more expensive (way harder to DIY as well). If you look at the commercial market you’ll see the only LED lights with controllers that allow for “lighting recipes” are upwards of $2000+.


The American Society of Agricultural and Biological Engineers has a new standard for Horticultural Lighting.

  • ANSI/ASABE S640 JUL 2017, Quantities and Units of Electromagnetic Radiation for Plants (Photosynthetic Organisms). " Developed over two years by an international team of experts from industry and academia, this standard brings some much-needed order to the metrics of horticultural lighting "
    Read more here :- http://agi32.com/blog/author/ian/