Electromagnetic Spectra of various Light Sourcces

Before addressing Red and Infrared light for your plant's benefits, I thought it would be good to actually know the spectra the sun produces to the many types of light bulbs that can be bought.

I also wanted to clear up what UVA and UVB are specifically. According to http://www.schoolgen.co.nz/ee/e4.factsheet.aspx, "ultraviolet radiation is the band of the electromagnetic spectrum with wavelengths just shorter than those of visible light. Sometimes UV radiation is sub-divided into UV-A (320-400 nm), which is harmless, UV-B (280-320 nm), which can cause sunburn, eye damage and skin cancers, and UV-C ( >nm) which may be lethal. Its corroborated! UVA radiation and thus the Royal Blue and UV LEDs are safe for our eyes; Though I still recommend using sunglasses since your eyes may become fatigued (tired) after looking at such high radiant levels and power we simply are not use to. -We squint our eyes at the sun not because of bright UV light, but because of the visible spectra we see; so looking at bright LEDs in the almost invisible spectra may not cause you to be aware of bright light but its still there. (What eyes 'see' and the brain 'sees' are quite different. Ok, enough with the cautionary compliance. Lets look at the electromagnetic scale firstly-

You should be able to notice how small the visible spectrum really is. Also notice where the micro-wave area is, just after far infra-red band. This is sort of a hint at to what Ill be addressing on the Red and IR spectrum blog post hopefully tomorrow.

So this is nice but... what does the sun actually produce, since thats what we are interested in artificially creating for the least amount of cost and highest amount of efficiency. We already know LEDs are the most efficient light source out there and will only become more efficient like CPU computer chips. The law I am referring to for computers is Moore's Law, and there is a correlate for LEDs -only makes sense since LEDs are Digital light. -Though I cant recall exactly where I saw this, probably when I was researching CREE on google finance's news ticker early April. So before I go on about sun and artificial lights, Im gonna pose a question to you- have you ever noticed how CFL light (the older ones I suppose now) would make brown/tan pants appear green? Or make medium rare steak look light green meat from Dr. Sue's Green Eggs and Ham story book? I'll answer this question in a moment.

First here is the Sun's spectrum-

Notice the units on the left side of the graph -this shows the amount of POWER (in watts) at each SPECTRA (in nano meters) shine on a one METER by one METER square at sea level. If you were to add up the power at each wavelenght you would then know exactly how much power per meter squared to supply to indoor grown plants. In theory its this easy, but remember this graph shows power relative to differing wavelengths.

Now, its apparently difficult to find spectral radiation distribution graphs for even the most common light sources, at least on line, but i did manage to find one from

Molecularexpressions.com -

So we can see very easily the one individual light source that most accurately emits spectrum closest to Noon Sunlight is the White LED. Also take into consideration the light plants absorb-

The White LEDs are very close to replicating the chlorophyll a & b as well as most of the beta-carotene pigment absorptions. Now since we've already looked at blue, royal blue and UV specific LEDs, we can get very close to 100%artificial replication of plant's needs in the blue spectrum!

I want to hear yawl's comments!

-Power Bower!