Mirrors as Reflectors

I was looking at GROW vids on youtube and found this:

http://www.youtube.com/watch?v=4nGheClD-lY&feature=related

and he is saying and showing how wonderful Mirrors work as reflectors. He even shows it..

What is your opinion of mirrors as reflectors?

Why are they used on flashlights and headlights of cars?

The only thing I would worry about with mirrors is the heat, and how they would contribute to temp build up. If you had good ventilation I s'pose it will work

Where are the scientist ?

They reflect virtually 100% of light, and obsorbe little heat. I don't know why people don't use them more, other than the price and heat issue. I have an image in my head right now of a nice box lined with mirrors and some CFL's for a tiny grow... hmm you got me thinking!!!

Plants absorb light best when diffused throughout it's leaves. Hot spots are counterproductive. You're asking those specific leaves that are receiving the bulk of the light to do the bulk of the work, then the plant has to transport all that energy throughout the rest of the plant.

mirrors do NOT reflect 100% of the light. i used to work at a factory that made them. even "The Best" mirrors out there are only 90% reflective. you lose light to the reflective surface. it is either absorbed or it bleeds thru.

white it THE most reflective color.

flat white paint.

mirrors are used to focus light all you want to do is reflect (bounce) the light back flat white paint will do this better then a mirror

Based on Wikipedia, typical mirror reflect 90-95% of light. Scientific mirror, 99.999% of specific light. Just for the facts I guess....

mannurse801 said:

Based on Wikipedia, typical mirror reflect 90-95% of light. Scientific mirror, 99.999% of specific light. Just for the facts I guess....

Click to expand...

my numbers were off a little.
same principle though.

Stole this from somewhere


Are mirrors good for reflecting light?


Mirrors waste energy by reflecting only a small fraction of the light that falls on them.

When light, which, like radio waves, is a form of electromagnetic radiation, strikes a metallic mirror the electrons in the metal move just as they do when a radio signal strikes an antenna. Pushing electrons around takes energy, which dims the reflected image.

Metallic mirrors reflect infrared light (heat) and if your mirror has imperfections this will cause hot spots, which can burn plants. Please note hot spots also apply to Mylar and Foil and IMO are not applicable to growers using small amounts of fluorescent lighting.

By using a mirror to reflect your light on a wall, you can test for imperfections, if you see an uneven image, with focused beams (normally located at the edge of the reflected pattern) these are known as hot spots and depending on the wattage of your bulb, may burn your foliage.

Metallic mirrors should not be used as a reflector for your grow room as minimizing light loss is important.

sounds like greg green

LOL Don't know where I got it but knew I had it saved somewhere

and i think it bounces it off in the opposite direction that it hits it. so if the light is shining down from the bulb above and it hits the mirror at say a 30 degree angle, then the light will be reflected downward at a 30 degree angle. i could be wrong.

mannurse801 said:

Based on Wikipedia, typical mirror reflect 90-95% of light. Scientific mirror, 99.999% of specific light. Just for the facts I guess....

Click to expand...

Anyone can write stuff in wikipedia

Mirrors absorb light

Just a side note: People argued about this in the forum's chat.

I got on video live and using a professional light meter showed that using ANYTHING glass with light will cut down on the available light your plants get. A pane of glass with mirror backing can cause an effective loss of 20% or more of the available light output.

Mirrors are very much useless. Yea it looks bright and looks nice and reflective but in all reality it's eating up your usable light. Get ANY "clear" pane of glass and turn it sideways so you can look along the plane. Notice how while it looks clear, from a side view it's green.

Why do we see plants as green? The same reason this glass appears green along the flat plane - it's absorbing red and blue light and only allowing mostly green to transmit/reflect back.

Mirrors = BAD. Flat white paint = optimum.

Oh, and please, please, don't rely upon wikipedia for resources. They are not only out of date but horribly inaccurate. The best mirror is actually made of liquid, not glass.

schooled........................

Seems like this question comes up alot...and we always get the same answers.....glass is a good insulator so it is going to absorb ambient temp and hold it and I'm sure some of the wasted 5-10% of light also turns into heat. There expensive...also heavy...and they can cut you I think mylar is just as reflective thinner lighter and cheaper...and like fdd2blk stated flat white paint is still the best...

it's "blinding" .....................

I've tested mirror lined grows and it doesn't work as well as flat white paint. And my testing invloved very high grade first surface mirrors used in projection systems. With low intensity lights you can get away with using them and not noticeably burn plants, but trying to do any focusing of light to a specific area or plant hasn't worked out. Nothing I tried worked better than plain old flat white paint.

I tried angling the walls of the grow, tried different types of light (cfl, small halides, small hps), tried mirrors as just the top of a box, etc. White paint always worked out the best.

I never had a light meter or anything, just compared one identical grow to another with the only difference being the type of reflective material and in some cases the shape of the walls of the grow.

thank you for your educational fact filled replys. The entire subject had me confused, but now I see the light!