Quote Originally Posted by outerspace

I heard some folks mention that the high-flux LEDs that require a heatsink are the only ones that work. It takes about 60 discrete 5mm LEDs to equal the luminous flux of 1 high power led. The thing is, 60 discrete LEDs are 1/5 the price of 1 high power LED and thats not including the heatsink. Additionally, high power LEDs have a much lower rated lifespan.
Good points all, but at this moment, ALL LEDs (high-output type which must be heat-sinked or not) are far too expensive, far too inefficient and don't produce near enough luminous output per LED device to be useful in a grow op.

The problem being that luminous output figures (lumens) added together are meaningless. Putting one light source next to another does not make either one any brighter. Lumens are a measure of perceived brightness, not a measure of photons being thrown at your leaves.

For example, if you have CFLs rated at 1300 lumens and you have 50 of them, you then have 50 light sources which are 1300 lumens 'bright,' not 50x 1300 lumens. Same goes for LEDs. The smaller, lower output LEDs, even if run in great numbers, will never be as bright as an LED with a higher luminous output.

Cannabis needs the brightness (or light intensity) to keep internodal lengths short and produce high-density buds. I have yet to see an LED grow that didn't show signs of serious light starvation.

LEDs are a terrific technology; the increases in output and reliability are coming by leaps and bounds in recent years... but it's not quite to the point where you can grow plants with them.
Al B. Fuct Reviewed by Al B. Fuct on . LED grow lights... input please. Hello guys, I'm exchanging eMails with a representative from a LED company. I asked him if they could produce a custom light for growing, and here's what he told me: Our options are as follow: 940nm, 850nm, 660nm, 630nm, 610nm, 590nm 570nm, 530nm, 510nm, 470nm, 460nm, 400nm and a total of 64 LEDs in the bulb. Rating: 5