I found this.. maybe its what you're looking for?
"Hi there. I'm currently doing my first LED grow, I must admit that it has turned into a full time experiment, however I am learning more with every mistake, and most of my mistakes were made due to a lot of disinformation on the internet about LED growlights, so here we go.
This has been going on for about three months now.
First off I have built the lights myself.
So I'm going to try to separate the fiction and bulls**t from the facts. There is no way that we can do any type of reliable mathematical equation to compare them to other type of traditional lighting as the color spectrum that a plant "sees"is approximately opposite to what a human eye perceives as brightness. So when we are talking about lumens or brightness we normally talk about white light when infact a plant "sees" blue content in the light for vegetation stages and red content for the flowers to form healthy. OK, blue colour that has produced the best vegetative growth was 465-470Nm. Now at this stage what we don't require is an LED with a viewing angle that is wide, if we have lots of LEDs we are better going for an LED with a vieving angle of approx 20 degree's. This means that more of the light output it being squeezed into a more directional beam. OK, so after trying different makes I eventually found the ones that I was after on the internet that actually performed amazingly well. I was only growing in soil but was getting veg growth of about 1 inch per day and not spindly either. So anyway that's me finished with experimenting with the veg state, just gonna build more of these babies to see what happens. Now I had started with doing the 75% red and 25% blue as stated in the bullshit on the net and the results were rubbish, but once I went pure 465Nm blue the plants started growing great. OK next big mistake I made, according to advice on the net--"plants require only red for flowering stage". Well this I found out to my horror is simply not true and I could have kicked myself for nearly killing my plants, because I assembled my homemade red lights and took out the blue ones,,oops. Well suffice to say that the BLUE LED's ARE STILL REQUIRED for the plants to survive and grow further in flowering stage however after putting back in the blue lights mixed with the red in equal quantities the plants are once again thriving and after 1 week the little buds are full of hairs (happy days). the blue Led's have an output of 8000mcd each over a viewing angle of only 20 degrees and the red ones have an output of 12000mcd over the same angle..Oh btw the colour spectrum for the red is 625-630Nm. Now that I have perfected all of this (I think), like I said I am gonna build more lights for more peformance as I am now in the process of building a large aeroponic unit for next grow so will post on here regular with pics when I get it all started. So anyway I am not selling anything nor do I proffess to be any sort of growing guru, I am just hoping to share my failures and succeses with you all to save you a bit of time money and trouble. Peace to all "
