As you are the most knowledgable here, I have two more questions if I may.

1. I can find nothing in the science that suggests a 6 or 8 to 1 red/blue ratio. Is this just attempting to copy HPS/MH spectra or are there real studies that support this? On one advanced cannabis board (engineers not growers), the conclusions was a blue to red ratio of 1.5 to 1 is best, while the absorption graphs look like it should be closer to the inverse, but nothing as extreme as all of the popular LED lights.

2. As you stated, and I have come to the same theoretical conclusion, that it's the photosynthetic photon flux density that is most important.

Let's assume these mfg numbers are accurate for this discussion. If I have a white LED that outputs 100 lumens/watt and has a higher total PPFD than either a 75 lumen/watt red or blue LED, (sorry no spreadsheet) why would I not go with all white LEDs? The spectra is something roughly like 40% blue, 10% green, 20% yellow and 30% red. (Don't hold me to those numbers.)

Any light you can shed (no pun) on these topics would be greatly appreciated.

Thanks!
RackitMan Reviewed by RackitMan on . Drowning in conflicting plant graphs - help! (LED) Still trying to design my LED light through clear understanding and not just mimicking. There is one photosynthetic response curve that shows yellow light has more effect than blue light and that green, while lower, is almost as useful. Other articles say green light may stunt plant growth and that yellow is not much more useful (despite the huge success of HPS). Then there is the photosynthesis action spectrum showing that violet/purple light (400nm) has the highest absorption peak Rating: 5