i need help on mirrors asap

NLXSK1

Well-Known Member
Mirrors are not effective reflectors as the light has to pass through the glass and back out to reflect back on the plants.

Flat white paint is a better reflector.
 

Spanishfly

Well-Known Member
Mirrors are not effective reflectors as the light has to pass through the glass and back out to reflect back on the plants.
Complete and utter NONSENSE. Yes, the glass will absorb a MINUTE amount of the light passing through it. But a mirror reflects FAR more light overall than a piece of white painted whatever, something like 98% of the incident light.
This is why you shave in a mirror and not a piece of white paint.
Where on Earth do these Old Wives´Tales come from????
So please, carry on using mirrors.
 

NLXSK1

Well-Known Member
NONSENSE. Yes, the glass will absorb a MINUTE amount of the light passing through it. But a mirror reflects FAR more light than a piece of white painted whatever. This is why you shave in a mirror and not a piece of white paint.
Really? How many growers do you know that use mirrors? Mylar maybe, but not mirrors....

And in response to the ridiculous shaving reference... I am not trying to grow my face.
 

Spanishfly

Well-Known Member
Totally agree, not many use mirrors, they are very fragile and expensive, lots of cheaper alternatives. But no scientific reason why not. You are just quoting ANOTHER Old Wives´Tale. You don´t want to grow your face? Probably a good reason.
 

Flatulent

Member
Spanishfly, that makes all sense. Some time ago I've asked myself why no one uses mirrors as they are much better reflectors. According to my research there are lots of people saying it's not good, because of this or that, but none of their arguments are based on logical facts.

The glass absorption is the funniest of all =D Sorry Mccoulin! =D

Maybe someone could make a test grow with mirrors, mylar and white paint so we can see the difference and get over with this discussion once and for all.
 

canefan

Well-Known Member
I used mirrors back in the 70's once for a grow inside, back then we didn't have the lights and technology that we have today. The biggest problem was the heat generated from the reflection of light or I guess that is cause. It tended to burn my plants and I gave up have a short try and never returned. Personally don't see why if couldn't use them especially to brighten the bottoms of your plants to get a little better penetration. Only trying this will answer your question, if it works for you great, if not you know not to use it in that manner again. Don't be afraid to try new methods, think outside the box on problem solving and in my opinion make sure that the advice you are getting is based on fact not wives tales. There is an awful lot of that in these forums. Good Luck and start a journal with your attempt so we can all see your results good or bad.
 

Airwave

Well-Known Member
Complete and utter NONSENSE. Yes, the glass will absorb a MINUTE amount of the light passing through it. But a mirror reflects FAR more light overall than a piece of white painted whatever, something like 98% of the incident light.
This is why you shave in a mirror and not a piece of white paint.
Where on Earth do these Old Wives´Tales come from????
So please, carry on using mirrors.
So prove that it's an old wives tale.
 

superbak3d

Well-Known Member
Complete and utter NONSENSE. Yes, the glass will absorb a MINUTE amount of the light passing through it. But a mirror reflects FAR more light overall than a piece of white painted whatever, something like 98% of the incident light.
This is why you shave in a mirror and not a piece of white paint.
Where on Earth do these Old Wives´Tales come from????
So please, carry on using mirrors.

Wow the ignorance of this post is incredible. It's not a wive's tale, its called science.

Mirrors are heat generators when it comes to light reflection. And the reflected light is non-benefitial to plants. Take baseball for example,

When a pitcher throws the ball and it is hit with the bat, the speed of the ball is doubled when its hit. A 90mph fastball = 180mph after direct contact.

The same princible works with lights and mirrors. When light is directed at a mirror, the reflection is amplyfied. What happens is you end up burning plants up. Same thing when you burn ants with a magnifying glass. Light + glass = amyplified heat. And no sorry, fans won't prevent the slighest bit of heat when it comes to magnified light.

Besides the fact that its scientifically stupid to try and grow with mirrors, its just stupid all around. First of all mirrors are thick, heavy, fragile, and severely limit your indoor grow options. You can't just "cut" a fan hole in a mirror. You' cant adjust or make changes to accompany your grow box dimensions. Mirrors are insanely difficult to work with.

This is why we use pure white paints and mylar. We get maximum reflectivity with no reflective-light heat amplification.

So spanish, make a 5x5x5 box lined with mirrors, get like a 600W HPS inside of it, and lets see how well you can grow. I bet your house sets on fire before you even get a sprout. Because im sure someone of your great intelligence knows what happens to glass when its exposed to heat spots for a prolonged period of time.
 

StonedBlownSkiller

Well-Known Member
Mirrors reflect light perfectly. so perfectly that it intensifies it and magnifies it. it DOES create hot spots. I had a huge mirror on my closet door beginning this current grow. I opened the door one morning and they were fell over from heat. removed the mirror and presto. back to doin good. Use em if u want but u might as well put a huge magnifying glass over ur shit. Its just glass.
 

gobbly

Well-Known Member
The reason you won't find scientific info on mirrors and spectral reflectivity is that mirror is a general term, not something specific. They are made from silver, aluminum, glass, and many other elements, most of which are what we are talking about when we talk about other reflectors that are "better than mirrors". If you look you will find all sorts of scientific studies on the spectral reflectance flux for many many different substances. Some things to take into account, as mentioned above heat, but also any time light goes through normal glass it is dimmed slightly as well as filtered of UV (there is special glass you can get that passes UV, as well as optical glass with low iron content, but this isn't what will be used on mirrors you buy).

If you look into it you will find the BEST reflectors (that are remotely affordable) will be polished spectral aluminum, and it's usually cheaper than a wall mirror (though not by much). This stuff is often used as the reflective surface in a mirror, so the argument of mirrors being good or not is dumb. What people are saying is that your typical house mirror is not as good a reflector as if you stripped off the glass (and sometimes the backing)...
 

superbak3d

Well-Known Member
Yea we are referring to household mirrors.

MJ plants only like to be burned when they are nested in a bowl!
 

golddog

Well-Known Member
For those who did not take Physics or Thermodymanics in college...

A mirror will not increase the heat output. It may however re-focus some light.

So outside I wouldn't use them. There is a lot of heat coming from the sun which can easily be refocused and burn your plants.

A 400 watt bulb will create 1364 BTU's. That's it. No mirror will increase the output from that source.

That said, I use Mylar, because Mirrors are hard to deal with and heavy and Mylar is cheaper and easy to use. :weed:

Wow the ignorance of this post is incredible. It's not a wive's tale, its called science.

Mirrors are heat generators when it comes to light reflection. And the reflected light is non-benefitial to plants. Take baseball for example,

When a pitcher throws the ball and it is hit with the bat, the speed of the ball is doubled when its hit. A 90mph fastball = 180mph after direct contact.

The same princible works with lights and mirrors. When light is directed at a mirror, the reflection is amplyfied. What happens is you end up burning plants up. Same thing when you burn ants with a magnifying glass. Light + glass = amyplified heat. And no sorry, fans won't prevent the slighest bit of heat when it comes to magnified light.
This is wrong , When you hit a 90 mph baseball with a bat swinging at 120 mph THEN you baseball may go 180 mph. This is due to the energy of the swinging bat.

Have you ever seen a bunt?
 

fdd2blk

Well-Known Member
Hey fdd....being on color subject, do you think black buckets for a soil grow is bad? would white be better? I was told to get black so light couldnt penetrate bucket and get to roots.
i prefer green, sometimes brown. i like the earth tones better. they match my decor.

;)
 
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