There have been a couple of posts regarding LED lights recently that I have stayed away from. Not because I didn't have an opinion but because I didn't have the language to say what needed to be said. It would appear we have at least one early adopter of the technology among our ranks and it should be instructive to say the least how the experience of living with LED turns out. It must be said however that the LED lights that I thought (hoped) would become the "next big thing" in the plant growing world were (are) what are known as "white light" LED. The lights Alex bought and the systems being sold on #bay are "monochromatic" LED.

In the past I have made mention of the fact that the sun is an "analog" light source much like the old fashioned vinyl long playing records. Incandescent lights are also analog light sources but of somewhat lower quality than the sun rather like the old fashioned analog tape recorders. HID lights are digital light sources with discrete 'bands' of frequencies represented with large 'gaps' of frequencies missing between the frequencies represented. Fluorescent light is also a digital light source and it is debatable which are closer to analog but different formulations of phosphors in various fluorescent lamps often have more 'bands' represented and thus a higher quality of light in much the same way that digital sound sources CD's, Digital Audio Tape can be recorded at different 'sampling' rates. The higher the sampling rate (the more bands) the closer to analog (sunlight) the technology. LED lights are like low end MP3 players. The most extreme compression (banding) of the light yet. Down to a single frequency of any particular color can be emitted with the right materials for the diode. This is great for efficiency and when perfected these lights can and will completely replace running lights, brake and tailights in vehicles etc. For plant growth we have seen that growth is possible under a less than perfect (analog) spectrum. When very high intensity is used with a less than perfect spectrum growth is still very much possible. We know that blue and red light are the primary growth frequency "bands" that are the most efficient at powering photosynthesis but I don't know how much research has gone into figuring out which frequency(ies) within the blue band and likewise the red that are the best to use for a monochromatic light emitter.

White light LED's get around the issue completely and use the emitter to activate a phosphor layer much like a fluorescent lamp. Efficiency is still very high but the spectrum now resembles something approaching a conventional fluorescent. I have no idea at all on exactly how the white light LED spectrum compares to CFL or HID. Currently they are used in flashlights and bicycle headlights and a 1 watt emitter (Luxeon Star) compares favorably with a 10 watt halogen lamp in brigtness. Keep your eyes on these white light LED's for possible use in indoor light systems. They, not the monochromatic red and blue light systems are going to be the lights you can actually live with day to day in your living space.

H