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Leds (light emitting diodes)

superimposedhope

Somewhat Unstable
Hey all,

Ok, I know HIDs (MH, HPS) and VHO CFLs are plenty to grow usually in terrariums or otherwise. However I have been reading about the possible future of LEDs in plant lighting.

LEDs (Light Emitting Diodes) are the little red(usually) light you see for power on most electronics. The solid plastic kinda bead lookin thing that lights up.
From what I understand LEDs also come in many, many nanometers of the spectrum. (I am not real good with the whole light spectrum technicalities). The idea is that by using say 600 LEDs in say 12 different ranges you have a light source whose light is only the useful ranges to plants. (Blue, red, white, etc...) Now that you have cut out unnecessary spectrum you also cut down on wasted wattage (watts=$$$ spent). Though as I have read all this is still being tested on different plants and as of now, it is suggested to supplement with a wide spectrum fluorescent. Do a google search for LED technology. Interesting none the less!

Joe
 
[b said:
Quote[/b] ]whose light is only the useful ranges to plants. (Blue, red, white, etc...)
white is a combination of all visible light frequencies so that would be useless
smile_n_32.gif

interesting though. I had wondered about that.
 
Alpha,
Like I said i am not very good with spectrum details but I have a general knowledge. It is an interesting idea though.
I have also been reading about sound frequencies and magnetic feilds increasing flowering and fuiting size and speeding up the ripening as well.

Joe
 
[b said:
Quote[/b] (superimposedhope @ Jan. 13 2005,9:02)]Alpha,
Like I said i am not very good with spectrum details but I have a general knowledge. It is an interesting idea though.
I have also been reading about sound frequencies and magnetic feilds increasing flowering and fuiting size and speeding up the ripening as well.

Joe
Interesting you mentioned the magnetic waves and plant growth. I remember seeing something on TV about how plants near power lines seem to grow faster due to being around the electrical/magnetic energies.
 
and I know they use "far red" mulch to ripen up tomatoes and other plants faster.
 
LEDs are advantageous because they are all solid-state light source.  Instead of using a heated element to produce a visible glow (incandescent/halogen), an LED  creates using similar semiconductor technologies to those involved in photovoltiacs- sort of the reverse process.  The wavelength (color) of light emitted depends on the size (energy) of the bandgap in direct LEDs.  Most common semiconductors (silicon, for example) have a low energy bandgap, so until recently most LEDs were at the long end of the spectrum (red) instead of blue.

As was mentioned, by their nature they produce a rather narrow spectrum of light, so you won't find "white" LEDs that mimic well the natural spectrum of the sun.  On the other hand, it might just work to provide two LEDs with the two wavelengths of light used in the principle photosynthesis reactions and have a very efficient way to light plants (which would look terrible to the eye).  However, many people (myself included) feel that plants need more than just those two wavelengths to flourish.  Flourescent light technology has had a sufficiently good headstart that it will remain the more energy-efficient way to light plants under those constraints for the foreseeable future.  But LEDs are improving at a faster rate, so it may only be a matter of time.

Of course, it's not like most growers even make use of the "best" lighting sources now from an efficiency standpoint due simply to costs, the persistence of traditional 'wisdom', and habit.  Many people still recommend and use the obsolete, flickery, and inefficient T12 flouresent bulbs, while the superior T8s have been required for all new industrial installations in many US cities for years now.  And the T5s are better yet, but you won't find those outside of high-tech aquaculture in Germany or high-end aquarium setups in the states.

That's my semi-too-often lighting lecture.
 
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