I don't understand such strong reactions online. We will never meet each other, our opinions are without consequence, and we can easily ignore each other in this format. I am here for unbiased INFORMATION, not bickering!
I have heard that 1 and 5 Watt LEDs are too weak for flowering, but 15 Watt LEDs can certainly do the job.
SO in THEORY, an array of 15W to 25W LEDs would be able to compete with HPS or MH systems. It would be expensive, yes. It would generate heat, although I can't imagine it as high as HPS. It would use less electricity, under 200W. The lower monthly electric bill would eventually equalize the higher investment, as would NOT buying replacement bulbs.
I have been influenced to believe that the LED technology, AS OF RIGHT NOW, is not cost-effective, or a working alternative to HPS.
This caught my eye, posted previously:
"...search PlanetGanja and Cannabis boards and you can find a lot of threads on the advanced theories and practice of growing using LEDs, it mainly comes down to most people attempting LED grows are using inferior quality or simply not powerful enough LEDs. From what I've personally seen and heard a proper setup using high power aka class 2 LEDs (Cree Xlamps, Luxeon Rebels, and Ledengin (which come from individual wattages of 5-15W) would basically demolish all other currently availabe forms of lighting in PAR and PUR. The main arguements going back and fourth are beam angle related, underdriving vs overdriving, the use of light near 660nm to create artificial darkness.
With that inmind however, one must note at the current prices for these higher end components, initial cost is much steeper, however once one factors in electrical costs (assuming you aren't solar, wind, etc) it does indeed even out, even at this moment. I believe in the November 2008 issue of High Times Jorge Cervantes reviewed a Spanish built UFO type LED vs a 400W HPS and a 600WHPS, the yeild to electrical price ration in this particular example was a net loss of 15% of yeild however when costs were factored in this was nearly even, and I in no way assert this is the most effective design.
Please in no way insult the thousands of man hours being put into the serious and hobbiest application of LED technology as a long term revolution in horicultural lighting.
I my self bought a Chinese panel which is apparently underdriven unnamed brand 10mm LEDs in an array of 72 Red vs 40 Blue. I was a victim of misrepresentation, but from that mistake I have done significant amounts of research on the topic. I'll put it to you like my forum buddy Weezard put it to me, 5mm? Not It, 10mm? Not It Either, 1W, Little Bit, 5W Getting There, 15W? Can Do. He's using an array of 4x RED 15W 1x BLUE 15W underdriven so his guesstimation of total used wattage is 60, and the guy seems upright to me and he claims to have colas the size of his fist under that unperfected but raw power set up...
Those Ledengin LEDs he is using are around thirty dollars per, but colas the size of my fist with a 60W power bill sounds like the future to me."