Mirrors ?

howdy all, i'm pretty new here, but have read alot on grow cabs and boxes. was just wondering if mirrors could be used as a reflective material on inside of grow box instead of mylar, foil, white paint, etc... ?? haven't seen anywhere where anyone else has used them,, just wondering.
 

bigv1976

Well-Known Member
Mirrors actually absorb light more than it reflects it and that is why most people dont use them. They can also create some serious hot spots on your plants.
 

growmo23

Active Member
Mirrors are not the best, they create focused hotspots on your girls. Go to the nearest outdoor outfitter and buy a couple mylar emergency blankets. They are cheaper, work better, and won't break and shatter glass all over your grow room by accident. Panda film is great as well, or you can paint the interior flat white (glossy white does the same thing-hotspots and uneven distribution). Hope it helps!
 

SFguy

Well-Known Member
i used foil before, and it drove me fucking bonkers!!!!! like rustling all the time from wind was sooo annnoying.. definitely go with some whit paint its cheap, bought the foil bubble wrap stuff cause its easy to use cause its rigid, and its re useable and cleans by spraying really easily... mirrors will make the room infinitely bigger(ever been in the carnival funhouse) and the light wont reflect back, diffrent concept than a "reflection"
 

SFguy

Well-Known Member
KILZ WHITE primer is great and also has something in it to help inhibit mold growth so that might help ya aswell good luck be creative =)
 

KushDog

Active Member
I "heard" mirrior dont work, but I have "SEEN" that they do work really good, I know a guy that built his reflectors out of mirriors, and he has the biggest buds i have seen on a plant. so sciens says no, real life experance says they work just as good as the next thing.
 

watchhowIdoit

New Member
The average mirror will absorb most PAR light. There are special optical mirrors that reflect PAR light but they are out of the reach of us closet growers....mirrors in general are very counter productive in a grow chamber.....
 
thnx to all who replied,, if and when i ever decide to make a grow box, i will not use my mirrors. i will save them in case i need them for a future project, i want to make a solar heater using my beer and pop cans,, and i can use my mirrors to direct more sunlight onto my solar heater,, as i said,, future project
 

Druzil

Member
I started to use foil. (Thought of mirrors as well) But was told that both reflect more heat than light, and that it will burn your babies. So I just taped/glued up typing paper all around the inside of my box and it seemed to work pretty well.
 

Brick Top

New Member
Mirrors have been talked about and tried by growers for many years. Every so often someone 'thinks outside of the box' and wonders about the same thing thousands or more others had previously wondered about. But Mirrors are not at all a good choice for a reflective material. Being smooth they reflect in a specular, or direct, way. Mirrors do not spread light around in all directions. Light striking a mirror is like a pool ball striking a rail, the pool ball will bounce off the rail at an angle like it went into the rail. Light coming off a mirror is the same.



Uneven surfaces, even micro-uneven surfaces, have a diffuse reflection, an indirect reflection that sends light rays off in many different directions. It is the same basic principal behind why a pebbled texture reflective hood is better than one with a smooth surface.




Why Does a Rough Surface Diffuses A Beam of Light?
For each type of reflection, each individual ray follows the law of reflection. However, the roughness of the material means that each individual ray meets a surface which has a different orientation. The normal line at the point of incidence is different for different rays. Subsequently, when the individual rays reflect off the rough surface according to the law of reflection, they scatter in different directions. The result is that the rays of light are incident upon the surface in a concentrated bundle and are diffused upon reflection. The diagram below depicts this principle. Five incident rays (labeled A, B, C, D, and E) approach a surface. The normal line (approximated) at each point of incidence is shown in black and labeled with an N. In each case, the law of reflection is followed, resulting in five reflected rays (labeled A[SUP],[/SUP], B[SUP],[/SUP], C[SUP],[/SUP], D[SUP],[/SUP], and E[SUP],[/SUP]).
 

Brick Top

New Member
What Reflective Materials can I use for my Grow Room?
[HR][/HR] Choosing the right surface for the walls of your grow room is very important, as up to 40% of your total yield comes from the edge, and the right wall surface can increase the amount of light those plants receive by up to 30%! Artificial lighting diminishes exponentially with distance, so it is important to ‘contain’ as much of this light as possible, and direct it accordingly. Reflective surfaces also help illuminate the lower portions of the garden, providing lower buds with light and heat energy.

To get the best results with your light and walls, it is important to get the walls as close as possible to your garden to ensure the least amount of light is wasted. As a caveat, the percentages provided are only useful as a general guideline, as they present the range of reflectivity of the particular surfaces. The high percentage presents the best possible circumstances for that material (for example a 99% reflectivity rating for Mylar sheeting would be under ideal conditions - no creases, completely flat, no discoloration, etc).

The best way to determine how well your grow room walls reflect light would be to purchase a light meter and measure your light directly; then take an opaque board and hold it a few inches off one of your walls with the light meter below the board in such a fashion that the light reflects off the wall and onto the light meter. You can then compare the difference between the two and determine a percentage from those numbers, the closer the two numbers are, the better your wall reflects light. It is important that in both measurements, your light meter is the same distance from the light, otherwise your results will be skewed.

Also important to note is that radiant light energy refers to electromagnetic (EM) radiation with a wavelength between 400-700 nanometers (nm) and radiant heat energy correlates to EM radiation with a wavelength between 800-2000nm.

Listed below are some of the most commonly used materials used for grow room walls:



Foylon:
A more durable version of Mylar, made of spun polyester fabric and reinforced with foil laminate. Foylon is resistant to most solutions, won't tear or fade, and can be wiped or washed clean.

A great solution for growers who are interested in long term use, and though it may be slightly more expensive than Mylar, its durability will more than make up for its cost. It has the ability to reflect about 95% of the light and approximately 85% of the heat energy, so a good ventilation system should be used in conjunction with Folyon.

A recommended method to attach Foylon to the walls would be using Velcro, as it makes taking it down for cleaning much easier and reduces the risk of tearing, creasing or bending it. If this is used for your walls, making sure you get it flush with the wall with no pockets of air between it and the wall to prevent hotspots.



Mylar:
A highly reflective polyester film that comes in varying thickness, the most common being 1 and 2 mm thick. The 2mm thick Mylar while not quite as durable as the Foylon, is fairly rugged. The 1mm thick Mylar tears fairly easily, so taking it down for cleaning is quite difficult without damaging it in the process. Both types of Mylar are able to reflect approximately 92-97% reflective, giving it the potential to be more reflective than Foylon, but because Foylon is more easily cleaned without damaging it as well as it being harder to crease, Foylon usually ends up being slightly more reflective. Important to note is that Mylar reflects radiant heat energy just as well as Foylon (around 85%), so proper ventilation is necessary if Mylar is used in your grow room. Attaching this to walls can be done in a similar fashion as Foylon, and the same caution should be used to avoid creating hotspots in your room. The 1mm thick Mylar stands a fair chance of being creased or ripped in the process unfortunately, even if Velcro is used to attach to the walls.

C3 anti-detection film:
A specialized type of Mylar that exhibits the same properties as the 2mm thick Mylar, but in addition to reflecting approximately 92-97% of the light, it also is 90% infrared proof, making your grow room all but invisible to IR scanning. This can also be attached in the same manner as foylon or mylar, and the same caution should be used to avoid creating hotspots in your room.

Flat white paint:
Self explanatory; a great option for large grow rooms or for people who are interested in a low maintenance wall. Flat white paint has the ability to reflect between 75-85% of the light, and does not create hotspots. Adding a fungicide is recommended when painting.

Glossy and eggshell whites not reflect light as efficiently as flat white. Semi-gloss paint for example, only has the ability to reflect between 55-60% of the light. Also important to remember when using paint is that any smears or blemishes on the surface take away from how reflective the wall is so care should be taken to avoid marking or staining the walls. Titanium white paint is very reflective; however it is usually only used on reflectors due to its high cost.

Elastomere paint

A rubberized roofing paint with 90% reflection. Good for grow boxes. Mildew resistant. Highly reflective.

Kool Seal White Elastomeric Roof Coating

Ultra high reflectivity
Forms a rubber-like blanket that expands and contracts
Adheres to almost any surface (very good on wood and metal)
Available @ Lowe's Home Improvement

White/Black plastic (also known as panda plastic or "poly"):

"Poly" is useful if you are setting up a temporary grow room or don’t want to damage the walls. Poly is easily cleaned.

The purpose of the black side is to not allow any light to pass through the plastic, which ensures your dark cycle remains dark. The white side is 75-90% reflective. Choose a 6 "mill" thickness of poly for maximum light blockage and durability.

If this plastic is put too close to the light, you will obviously melt it so be careful!. Panda plastic does not create hotspots. Poly can be attached to the walls by using carpenter’s nails or using tape glue or similar means. This can be used as a cheap alternative to Mylar if painting your grow room is out of the question.

Polystyrene Foam Sheeting (more commonly known as Styrofoam):

This is excellent for harsh environment grow rooms (your attic for example), provided you have a good ventilation system and a way to keep the temperatures from rising too high (an a/c unit or similar) as it is an excellent insulator.

It is also a great material for use in a temporary setup or for use as a "travelling reflector" on a light mover, where weight is a concern. It is approximately 75-85% light reflective so it is comparable to using a flat white paint. Foam will not create hot spots. Rigid foam can be purchased in sheets, and can be used as a free standing wall or can be taped, glued or nailed to the wall, the last generally being the most successful method.



Emergency Blankets:
These are ultra thin polyester blankets that are sold in most camping stores and are constructed of a single layer of polyester film that is covered with a layer of vapor deposited aluminum.

It is not very effective at reflecting light because it is so thin. Holding it between you and a light source, many small holes are noticed at the intersections of creases and the entire blanket is translucent to begin with, this coupled with the many creases that are in it when you purchase it takes away a significant amount of it reflectivity. It is very easily creased as well which also detracts from its ability to reflect light. And while it is reflects nearly 90% of radiant heat energy, it is only able to reflect around 70% of the light.

The largest advantage of using this type of material is that it is very cheap and therefore easily replaced. Emergency blankets can create hotspots if not attached flush to the wall so it is important that no air gaps exist between it and your supporting wall. The easiest way to attach this is to use tape (Aluminum or metal tape is recommended), as it tears very easily once it is cut or punctured.

Aluminum Foil:
Aluminum foil is no more than 55% reflective - if used, make sure that the dull side is the one that is used to reflect the light. When it becomes creased its reflectivity is even lower (around 35%.) It is also very dangerous to use because it creates hotspots easily, is electrically conductive, and is a fire hazard when it is in close contact with HID lighting. Attaching this to walls is a pain and usually using aluminum tape or glue is the best way. This should only be used as a last resort, and even then its usefulness is questionable.
 

Brick Top

New Member
so in other words the light from a mirrior will be the same as from the light sorce it's self? I agree that a difused light is better, but a smooth suface is going to reflect the light in a more direct/intense way.
Inexperienced growers get to hung up on the percentage of the reflect-ability of a reflective material, how "intense" the reflective ability of a material is. Most do not know the Law of Reflection, nor when told of it do many care how it determines what is a good reflective material for looking at yourself and what is a good reflective material for growing plants of any type.



i guess the direct light from my light is bad and i should keep my plants away from the direct beem and just use the refletion to grow my plants?
That makes no sense whatsoever given that the topic is about reflected light rays, not direct light ray, how light rays reflect off of mirrors compared to how light rays reflect off other reflective materials.

Have you never noticed that the best, most efficient, most effective, highest dollar reflective light hoods are pebbled aluminum rather than smooth aluminum or some other smooth surface material? If you have noticed have you ever wondered why that is?

What is the job of a reflective light hood? To reflect light rays in the most efficient, most effective manner giving the best overall coverage of reflected light rays. The job of reflective material for walls of grow rooms or grow tents or grow boxes or whatever is exactly the same.


A light beam can be thought of as a bundle of individual light rays which are traveling parallel to each other. Each individual light ray of the bundle follows the Law of Reflection. If the bundle of light rays are incident upon a smooth surface, then the light rays reflect and remain concentrated in a bundle upon leaving the surface.

Hot spots or flash points occur when bundles of concentrated light rays which are traveling parallel to each other converge. In grow rooms, the hot spot phenomenon is dramatically increased when using a material with a specular reflection as a supplementary lighting source to the grow lamps.


Learn it, live it, love it.
 

Brick Top

New Member
" would be under ideal conditions - no creases, completely flat, no discoloration"

so do we want flat / or difused??????
You are confusing a material lying flat on a wall and a material with a smooth surface. They are two totally different things.

You want flat reflective material, as in not lumpy and bumpy or with folds or creases, but you want a porous or micro-porous surface that will provide a diffuse reflection rather than specular reflection.
 

KushDog

Active Member
What Reflective Materials can I use for my Grow Room?
[HR][/HR]Choosing the right surface for the walls of your grow room is very important, as up to 40% of your total yield comes from the edge, and the right wall surface can increase the amount of light those plants receive by up to 30%! Artificial lighting diminishes exponentially with distance, so it is important to ‘contain’ as much of this light as possible, and direct it accordingly. Reflective surfaces also help illuminate the lower portions of the garden, providing lower buds with light and heat energy.

To get the best results with your light and walls, it is important to get the walls as close as possible to your garden to ensure the least amount of light is wasted. As a caveat, the percentages provided are only useful as a general guideline, as they present the range of reflectivity of the particular surfaces. The high percentage presents the best possible circumstances for that material (for example a 99% reflectivity rating for Mylar sheeting would be under ideal conditions - no creases, completely flat, no discoloration, etc).

The best way to determine how well your grow room walls reflect light would be to purchase a light meter and measure your light directly; then take an opaque board and hold it a few inches off one of your walls with the light meter below the board in such a fashion that the light reflects off the wall and onto the light meter. You can then compare the difference between the two and determine a percentage from those numbers, the closer the two numbers are, the better your wall reflects light. It is important that in both measurements, your light meter is the same distance from the light, otherwise your results will be skewed.

Also important to note is that radiant light energy refers to electromagnetic (EM) radiation with a wavelength between 400-700 nanometers (nm) and radiant heat energy correlates to EM radiation with a wavelength between 800-2000nm.

Listed below are some of the most commonly used materials used for grow room walls:



Foylon:
A more durable version of Mylar, made of spun polyester fabric and reinforced with foil laminate. Foylon is resistant to most solutions, won't tear or fade, and can be wiped or washed clean.

A great solution for growers who are interested in long term use, and though it may be slightly more expensive than Mylar, its durability will more than make up for its cost. It has the ability to reflect about 95% of the light and approximately 85% of the heat energy, so a good ventilation system should be used in conjunction with Folyon.

A recommended method to attach Foylon to the walls would be using Velcro, as it makes taking it down for cleaning much easier and reduces the risk of tearing, creasing or bending it. If this is used for your walls, making sure you get it flush with the wall with no pockets of air between it and the wall to prevent hotspots.



Mylar:
A highly reflective polyester film that comes in varying thickness, the most common being 1 and 2 mm thick. The 2mm thick Mylar while not quite as durable as the Foylon, is fairly rugged. The 1mm thick Mylar tears fairly easily, so taking it down for cleaning is quite difficult without damaging it in the process. Both types of Mylar are able to reflect approximately 92-97% reflective, giving it the potential to be more reflective than Foylon, but because Foylon is more easily cleaned without damaging it as well as it being harder to crease, Foylon usually ends up being slightly more reflective. Important to note is that Mylar reflects radiant heat energy just as well as Foylon (around 85%), so proper ventilation is necessary if Mylar is used in your grow room. Attaching this to walls can be done in a similar fashion as Foylon, and the same caution should be used to avoid creating hotspots in your room. The 1mm thick Mylar stands a fair chance of being creased or ripped in the process unfortunately, even if Velcro is used to attach to the walls.

C3 anti-detection film:
A specialized type of Mylar that exhibits the same properties as the 2mm thick Mylar, but in addition to reflecting approximately 92-97% of the light, it also is 90% infrared proof, making your grow room all but invisible to IR scanning. This can also be attached in the same manner as foylon or mylar, and the same caution should be used to avoid creating hotspots in your room.

Flat white paint:
Self explanatory; a great option for large grow rooms or for people who are interested in a low maintenance wall. Flat white paint has the ability to reflect between 75-85% of the light, and does not create hotspots. Adding a fungicide is recommended when painting.

Glossy and eggshell whites not reflect light as efficiently as flat white. Semi-gloss paint for example, only has the ability to reflect between 55-60% of the light. Also important to remember when using paint is that any smears or blemishes on the surface take away from how reflective the wall is so care should be taken to avoid marking or staining the walls. Titanium white paint is very reflective; however it is usually only used on reflectors due to its high cost.

Elastomere paint

A rubberized roofing paint with 90% reflection. Good for grow boxes. Mildew resistant. Highly reflective.

Kool Seal White Elastomeric Roof Coating

Ultra high reflectivity
Forms a rubber-like blanket that expands and contracts
Adheres to almost any surface (very good on wood and metal)
Available @ Lowe's Home Improvement

White/Black plastic (also known as panda plastic or "poly"):

"Poly" is useful if you are setting up a temporary grow room or don’t want to damage the walls. Poly is easily cleaned.

The purpose of the black side is to not allow any light to pass through the plastic, which ensures your dark cycle remains dark. The white side is 75-90% reflective. Choose a 6 "mill" thickness of poly for maximum light blockage and durability.

If this plastic is put too close to the light, you will obviously melt it so be careful!. Panda plastic does not create hotspots. Poly can be attached to the walls by using carpenter’s nails or using tape glue or similar means. This can be used as a cheap alternative to Mylar if painting your grow room is out of the question.

Polystyrene Foam Sheeting (more commonly known as Styrofoam):

This is excellent for harsh environment grow rooms (your attic for example), provided you have a good ventilation system and a way to keep the temperatures from rising too high (an a/c unit or similar) as it is an excellent insulator.

It is also a great material for use in a temporary setup or for use as a "travelling reflector" on a light mover, where weight is a concern. It is approximately 75-85% light reflective so it is comparable to using a flat white paint. Foam will not create hot spots. Rigid foam can be purchased in sheets, and can be used as a free standing wall or can be taped, glued or nailed to the wall, the last generally being the most successful method.



Emergency Blankets:
These are ultra thin polyester blankets that are sold in most camping stores and are constructed of a single layer of polyester film that is covered with a layer of vapor deposited aluminum.

It is not very effective at reflecting light because it is so thin. Holding it between you and a light source, many small holes are noticed at the intersections of creases and the entire blanket is translucent to begin with, this coupled with the many creases that are in it when you purchase it takes away a significant amount of it reflectivity. It is very easily creased as well which also detracts from its ability to reflect light. And while it is reflects nearly 90% of radiant heat energy, it is only able to reflect around 70% of the light.

The largest advantage of using this type of material is that it is very cheap and therefore easily replaced. Emergency blankets can create hotspots if not attached flush to the wall so it is important that no air gaps exist between it and your supporting wall. The easiest way to attach this is to use tape (Aluminum or metal tape is recommended), as it tears very easily once it is cut or punctured.

Aluminum Foil:
Aluminum foil is no more than 55% reflective - if used, make sure that the dull side is the one that is used to reflect the light. When it becomes creased its reflectivity is even lower (around 35%.) It is also very dangerous to use because it creates hotspots easily, is electrically conductive, and is a fire hazard when it is in close contact with HID lighting. Attaching this to walls is a pain and usually using aluminum tape or glue is the best way. This should only be used as a last resort, and even then its usefulness is questionable.

so I should cover my mirrors up with mylar? Should i make it as flat and smooth as possable, kinda like a mirror finish
 

Brick Top

New Member
so I should cover my mirrors up with mylar? Should i make it as flat and smooth as possable, kinda like a mirror finish

A question was asked. The singular correct answer in the thread was given. Some want to reject it, others want to argue it and others question it.

Forget everything I posted. Do not bother to research what sort of light reflection horticultural sciences has long known is best for growing plants, ignore the effects of diffuse reflection in nature (ouside plant growing), don't bother to Google or to go to a book store or a library and pick up a book or three on the subject. Do not concern yourselves with proven facts and instead everyone should believe whatever it is they like, want or need to believe and go with that.
 

smokiemcbowl

Well-Known Member
Id listen to brick top lol from what iv seen hes on his shit and pretty much always has the correct answer. Personaly i use space blankets for my box. Super cheap (like $2 at walmart) and it works. Not mylar but its the best thing iv found for my box. Just puttin out my 2 cents.
 

KushDog

Active Member
i went into my back yard and did a test. I took a large mirror and faced it at the sun, and i reflected to light from the sun Though a window in my house and lit up a wall..... how did i reflect light off a mirror if it aborbs the light?????? maybe my mirror must be broke or something. to be fair i will try a differnt mirror, because the one i use could have malfuntioned.
 
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