Quote Originally Posted by khronik
You're missing the one major advantage of LEDs here, that being that LED systems only output light on wavelengths that is ideal for plants to use.
Unfortunately, plants don't live on just a couple of narrow peaks in the spectrum.

Yes, cannabis prefers a blue emphasised spectrum for veg and a red-orange spectrum for flowering- but notice I said spectrum, not wavelength.

When we say wavelength, we're referring to a pronounced, narrow bump in the spectral curve around a central frequency. 'Spectrum' refers to a broad band of different wavelengths between an upper and a lower limit, with light of relatively equal amplitude (intensity) between the points.

Back to first principles. You can bet that the plant has evolved to grow in sunlight. Whatever lighting system you cook up, the closer it is to Old Sol, the more likely cannabis will like to grow under it. The sun is a broadbanded light (and other EM radiation) source. Current tech LEDs are not.

We know HPS is broad enough and produces enough luminous output in suitable ranges to flower cannabis effectively (and is no slouch vegging, either). Fluoros are broad enough but lack intensity. LEDs lack both breadth of spectra and output intensity.

It's gonna happen- someone will soon cook up LEDs bright and broad enough to be car headlights. When that happens, LED grow lights effective for cannabis might start to become a practical possibility.
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