Why are mirrors bad at reflecting light?

[pcmoe5000]

Well here is the story. I was sitting with a bud and we were discussing a grow setup and it was brought up that he wanted to use mirrors and aluminum foil for the light reflective property's of this grow. So me a big user of 420mag have come across over and over respectable growers saying that mirrors are bad at reflecting light. So I try to tell my bud that mirrors are not that great for growing and he looked at me like I was a dumbass. Unfortunately I was not able to tell him why this is so. So can anybody tell me why this is? I am now quite curious myself as to why mirrors are not good at reflecting light. Any good answers??

Went ahead and did a poll on mirrors good or mirrors not good....

 

[zierf]

i'm not an expert or anything. But from what have always been told is that glass eats up the light to some extent. If you have a light hood with tempered glass. The light loses some of its strength passing threw the glass( i was told about 5% or so). So if you use a mirror the light has to pass the glass on the way in and then again on the way out.

 

[The Weed]

Here is some answers too,...Is Mirror a good reflective surface?

 

[BWC BayArea]

Read this>What Reflective Materials Can I Use For My Grow Room?. When I asked the mirror question, I was told that they "eat" more light than they reflect. Foil creates "hot spots". Check that link out.

 

[Flurple]

impurities in the glass convert light into heat. cheap mirror glass will probably be as bad as you can get with wasting light. just use mylar or flat white paint. large sheets of white paper taped to the walls are better.

 

[LadyToker]

I cannot believe how innaccurate information can be gotten from just "hanging out".

I am an Electrical Designer which means I design lighting systems. I have worked on Thousands of projects but the ones that stand out for this excersize is The Butterfly House and Moody Gardens.

But just to make certain, I have solicited the Electrical Engineer I worked under and here is his response What it lacks in verbosity it makes up in summary:



Mirrors will indeed help and they will reflect a small amount of heat too, but not as much as they do light. Try and see......

 

[LadyToker]

Thankyou so much for taking the time to write information to help these growers. It takes time and effort.

Sadly, you have posted this information all over the net and it is wrong. I am sure this is due to what you have heard elsewhere and point of information can change everything

However, the MIT theory on the net says: Metallic mirrors work pretty well, but they have limitations. The most important is that they waste energy, absorbing a small fraction of the light that falls on them.

..and no I am not going to follow up on all the sites you have done this on. I do not understand why you rewrote this info.

When I initially came on here it was for a book and other informational materials regarding marijuana. Though I do not grow weed, it doesn't mean I do not know anything.

I am an Electrical Designer which means I design lighting systems. I have worked on Thousands of projects but the ones that stand out for this excersize is The Butterfly House and Moody Gardens.

But just to make certain, I have solicited the Electrical Engineer I worked under. I sent him what you wrote verbatim and here is his response What it lacks in verbosity it makes up in summary:



Mirrors will indeed help and they will reflect a small amount of heat too, but not as much as they do light. Try and see......

 

[theengineer]

impurities in the glass convert the light to heat? I've heard it all now lol, this myth is right up there with the one that fan leave are parasitic and must be defoliated

 

[LadyToker]

WHere were you when this first was posted? Not your fault.
Sadly, the original post is ALL OVER THE NET. And it is under "How to grow..." right here on this site.

The sad thing is everyone of the follow ups in the thread took him verbatim and the poll said 100% of the folks thought NO MIRRORS was the best. 100%!!!!!!!!!

This is one of the most expensive crops to grow..

NEVER take anyone at their word when it comes to money and how to lose it.

Even what I write needs to be researched.

 

[theengineer]

I veg awesome plants under tinfoil reflectors, and guess what? not one single burn. anywhere

 

[LadyToker]

I veg awesome plants under tinfoil reflectors, and guess what? not one single burn. anywhere

I know....right?

I wish I could chat with the original poster who baited everyone with the article and ask him what his motive was. It was apparent he cut and pasted the article. (original 420 article from 2004)But then he edited it. WHen it would have been far easier if not responsible to just leave the article as it was. I am truly perplexed. What was his agenda?

Sadly the original thread regarding mirrors was written MANY years ago and I am just now correcting it.

In the end, it really is common sense. A true mirror gives you an exact duplicate reversed, why would it NOT reflect the LEDs and UV lights exactly? It isn't as if these lights have an organic structure that cannot be seen.

And finally, why do you think fixtures have REFLECTOR HOODS? Lighting supply companies would have dropped them long ago off their Plant-Gro fixtures if they have no basis in fact.

Here is the original MIT article:
M.I.T. Scientists Turn Simple Idea Into 'Perfect Mirror'

I wish I had the room and the gumption to start a garden. All my expertise is in the lighting at this point.

And thanks for following. Perhaps you can help spread the word.