Mirror Mirror On The Wall

[XRey]

Maybe your growing space is not perfectly square or the roof is inclined making the use of a grow tent complicated.

Just drop by a used furniture store and check for real mirrors.

Oftentimes they have a big choice of used bedroom mirrors

They're usually very cheap compare to a tent and they're hard to beat for reflecting photons!

Just make sure you make a solid installation so they don't fall over.

Happy growing

 

[TorturedSoul]

Mirrors are inefficient at reflecting light, but you can prime and paint them with a pure/bright white (flat or close to it preferred), lol. Helps significantly on the (light) reflectivity.

 

[nivek]

mirrors and grow rooms are a bad idea for thirteen reasons

 

[XRey]

Mirrors are inefficient at reflecting light, but you can prime and paint them with a pure/bright white (flat or close to it preferred), lol. Helps significantly on the (light) reflectivity.

Then why growing tents are not painted white?

 

[XRey]

mirrors and grow rooms are a bad idea for thirteen reasons

Which are....?

 

[nivek]

ok,,

one,, one has to look at oneself

two,, they can break

three,, to be continued

 

[XRey]

It figures...

 

[nivek]

Well. I was obviosly not serious. So i thot.

One reason is reason enuf. A mirror would create hotspots like a magnifying glass. Could burn your house down never mind your plants

 

[XRey]

And you're still obviously not serious.
...been smoking?

 

[TorturedSoul]

Then why growing tents are not painted white?

Most of them did use a white interior material until some asshat company decided to cheap out on materials and used something that offgassed toxic fumes that killed people's plants. Then the outrage/panic that ensued caused just about everyone to stop buying from that and every other company who used white reflective material.

But you can still find them if you care to look for them, and from some decent manufacturers, too. For example:

https://www.homebox.net/en/

Mirrors... No, just... no, lol. I can't think of a single reason for using one, but as for why you shouldn't, well:

By their very nature, mirrors create hot spots. Think about it. If they reflected in a diffuse way, you wouldn't be able to see any details in your reflection when looking at one . So in terms of this thing, their score is... zero. At the very other end of the scale is flat white paint. Stand in front of a white wall. Can you see yourself? No? 'nuff said on "diffuse."

Then there's the whole question of reflectivity of light. First, unless you have many thousands of dollars to spend on a mirror(*), you're just going to be buying the kind of mirror that you'll find on a medicine cabinet, hanging on the wall, mounted to the bathroom door, et cetera. They reflect more light than a black wall, lol, but what doesn't? Light has to pass through a piece of glass, which will typically "eat" around 9% of it. Then it reflects off of the underlying surface - which absorbs certain frequencies (which ones vary according to the actual composition of that material). Due to the fact that it's not required for their intended purpose, that material isn't going to reflect back a whole lot of the light. And then... that light has to pass through the glass again.

I could go on, but you either get the point already or not and, if not, further explanation wouldn't help. Figure on the average Suzie Homemaker mirror being able to reflect about 40% of light back into your grow room.

Those sheets of white poster board you can find in the school supply section of your local grocery store for a dollar or less are significantly better - they reflect around 60% of the light that hits them (the rest is either absorbed or passes right through it).

(*) If you DO have really deep pockets, though, you can pick up a decent diffraction limited one for a few thousand dollars. It'll be about 8" in diameter . Or you can really spend some money on a dielectric mirror. Those are capable of reflecting a considerably higher percentage of the light that hits them - but only in a very narrow frequency range. Not good enough, lol? Okay, dig a little deeper - a few million and up - and you can have the folks who build mirrors for those huge optical telescopes you find in observatories build you a mirror. But better plan on being patient - those things can take a year or longer to construct.

Me, I'd just prep the wall surfaces, apply a high quality primer, and then walk into my local Home Depot and buy some Behr Marquis Ultra Pure White paint, and paint the walls. It's around 94% reflective. . . .

 

[XRey]

Thanks a lot for your highly reflective explanations! You got me 3/4 convinced. I understand that the glass from a mirror absorbs a certain percentage of light. OK mirrors are out. But what about things that do not have a glass like highly polished metals or even aluminium paper ?
It's not that I don't believe you but I checked at Behr Marquis Ultra Pure White paint didn't find the 94%
Hoping for an answer for the 1/4
Thanks again.

 

[dakotamoon]

There is a YT video out there .. some guy takes a light meter and creates a grow tent with a hula hoop (I kid you not) .. when he finishes his $20 tent with mylar - and then sticks in a light meter: .. the light meter readings go up 100% (In the hot zone) vs. a white background, he claims? No way to verify the experiment, but interesting. I'd include the link here, but it's not encouraged.

 

[HydroponicFireman]

Grow shops sell 30ft rolls of mylar material for like $15. You can make any size grow room you want just hang it from the ceiling and cut to size! Mirrors are terrible for reflecting, I think I read somewhere they only reflect 20-30% of light and its highly concentrated to a certain area. They absorb a lot of light, too. Mylar is made for reflecting light efficiently, I believe around 70% or so.

 

[Dankman_420]

I've used the bubble wrap mylar insulation from home Depot. It works great IMO. But it ain't cheap

 

[TorturedSoul]

I've used the stuff in the past, too, but never bought it. Next time you want some, try asking around at home (et cetera) construction sites if you can have any leftover tag-ends of their rolls. I don't know what it measures, but I've still got part of (the end of) a roll left. It's about knee-high (when laid on its side).

I've gotten other "semi-useful salvage" from job sites, too.

 

[TorturedSoul]

Here's a video in which they take light measurements inside a name-brand grow tent, then stick sheets of white Orca film onto the walls ("live"), and you can watch the meter readings climb.

Another one, this one shows a white grow tent in comparison with a silver mylar one. Testing performed at the Electrotechnical Testing Institute:

This video shows the live recording of a test about PAR light reflection inside grow tents, with different reflective materials (White PE and Silver/ Mylar). The result is surprisingly different from the common opinion on this topic. The famous Czech author of the book and articles about indoor growing, Mr. Jose, was in process to write a new book. On the subject of light- reflecting materials he found during his research, very different information. Because he wanted to pose in his book only accurate information he had to do this test, by using the equipment and knowledge of the renowned Electrotechnical Testing Institute from Prague. www.ezu.cz