What Reflective Materials Can I Use For My Grow Room?

[dc534]

I think people put to much into trying to get the most reflectivity. Flat white paint is probably most anyone needs. If using CFL's the bulbs are usually placed only a few inches from the plant so you are not gaining much by going for some ultra high reflective material. If I double the distance to a light source the observed intensity is decreased to (1/2)2 = 1/4 of its original value. So basically every foot you are decreasing the intensity of the light to 1/4 of its original. So after just 3-4 feet you might be gaining an extra 1/12-1/16th the intensity of your lamp. So its rated at 10000 Lumens you would be gaining a whopping 830 Lumens but that is if the light was reflected at 100% which it is not. So as you can see there is not much difference between 80% or 95% reflectivity the amount of Lumens reflected is between 650 for a flat white reflecting 80% or 790 using a more reflective material like mylar at 95% for a 10000 Lumen output lamp that is 3ft away. This amounts to something like a little less than a 10 watt cfl bulb. I am not sure about you but I am not worried about only gaining an additional 140 lumens when choosing between a flat white or a more reflective material like mylar. Heck I have more than 6000 lumens per square foot already so 140 is a drop in the bucket and I am not going to see some exponential growth in the plants.

 

[casey2003]

That looks like black & white itt looks perfect for the job, but as mentioned before flat white paint works just as well

 

[totemic]

I've been using silvery bubblewrap-like material, like you find windshield sun shields sometimes made of. I got mine for free out of a dumpster, but I don't think it'd be very expensive. I stapled it to my walls with a staple gun and 1/2" T50 staples. Because it's got bubble wrap bubbles in it, it's surface is crenelated, so it might not be ideal for light, but it has been working fine for about a year now for me. It also has some insulating value to it, blocking heat from passing though it, but not a lot of thermal resistance. Maybe R-2 or R-3. It's surface is aluminized, and has begun flaking a bit for me, when I wipe dust off, so mine is probably due for replacement after my next grow.

Hey, how has the windshield cover material worked for your room? I'm using it also at the moment.. Any issues like hotspots? Still using it?

 

[Ascended Master Kief]

It works great, totemic. Still using it. Mine was old when I got it, and the aluminum is flaking a little. But I think brand new, they'll last several years or more. Try not to rub it, and avoid letting the plants rest against it, and it should work very well. No hot spots. The crenelated surface really helps spread light around evenly. With the LED I'm running now, I could probably get away without reflective walls, but I'm not going to remove the stuff. With the CFLs I was using, I'd have had almost no usable light on the plants without the windshield stuff. How did you attach it to your walls? I used T-50 3/8" staples.

 

[onewarmguy]

Hey SmokeyMcPot, you mean 1 or 2 mils (1/1000") thick not 1 or 2mm, correct?
"Mylar:
A highly reflective polyester film that comes in varying thickness, the most common being 1 and 2 mm thick."

 

[xave420]

I bought some big pieces of white low gloss poster board and taped it all around the walls of my grow area.

 

[gracegrove62]

I noticed that mirrors are not mentioned. Are they of any use in a grow room?

 

[TorturedSoul]

Hi, gracegrove62. I see that this is your first post, so welcome to 420Magazine!

I noticed that mirrors are not mentioned. Are they of any use in a grow room?

Very, very little use, lol. They actually do not reflect a high percentage of light back. Any light that does get reflected must pass through the mirror's glass twice.

If you cannot escape using a mirror in your grow room, give it a coat of good primer and then a coat or two of bright flat white paint . (Or use an eggshell or satin finish so you can wipe it down occasionally, but - IIRC - flat is said to be best). Just be sure that the white paint you are getting is actually white and not simply "white," lol. I once helped a guy paint the outside of his house and the paint he used was labeled as white... But in the sunlight, it looked sort of a bluish gray. We joked that they should have called the stuff "Not Quite White."

Or cover the mirror with mylar.

But you'd probably be ahead to just remove the mirror entirely. No sense taking a chance on seven years' worth of bad luck....

 

[gracegrove62]

I like that idea...Layes, here I come! They may be quite flammable though.

 

[gracegrove62]

Hahahhahaaaa!!! Awesome response!! I am sold on the "real white/real white white" eggshell white. I like that it's cheap, I already have some. The mirror I was referring to is quite large ( 3 x 4 ) and can be place against the wall at an angle to reflect up under the plants as well. I have set up this gro-space in a closet that has a sloping ceiling - not a square space at all. There is a heater in there now starting some seeds for my "summer garden". If this works, I will have a "winter garden" too.
I will paint the mirror and space flat white white as you have suggested, great idea!
Thank you for your help, you just saved me some money!

 

[gracegrove62]

I read somewhere that the uv mylar, reflects a lot of the heat signature. Is this true? I went into Kent to see if they carry it but they don't. My sh-peal is that I have three large front windows I need privacy for and UV filtering....sound OK? I am going to try some local privacy window treatments....wish me luck.

 

[onewarmguy]

I"m planning on using some 60 mil white PVC roofing material with a reflective index of 0.86 as a liner, any comments?

 

[Alex420]

Hahahhahaaaa!!! Awesome response!! I am sold on the "real white/real white white" eggshell white. I like that it's cheap, I already have some. The mirror I was referring to is quite large ( 3 x 4 ) and can be place against the wall at an angle to reflect up under the plants as well. I have set up this gro-space in a closet that has a sloping ceiling - not a square space at all. There is a heater in there now starting some seeds for my "summer garden". If this works, I will have a "winter garden" too.
I will paint the mirror and space flat white white as you have suggested, great idea!
Thank you for your help, you just saved me some money!

I would strongly recommend against using mirrors. Not only are they not very reflective of light (like 50% compared to mylar or white paint's 85%), and easily breakable, but most dangerous of all is the fact they even the slightest imperfection in the glass can create hot spots not only on your plant but also behind the mirror, if the lights are strong enough, creating a fire hazard for your entire building. I used them before I found out this information and I seen remarkable improvements in temperature control and light dispersion upon getting rid of mine. There are much cheaper and easier to install products out there, some of which might be able to be found around the house (white paint, reflective paint, mylar baloons, emergency blankets, panda plastic, etc) that are safer.

 

[Alex420]

I read somewhere that the uv mylar, reflects a lot of the heat signature. Is this true? I went into Kent to see if they carry it but they don't. My sh-peal is that I have three large front windows I need privacy for and UV filtering....sound OK? I am going to try some local privacy window treatments....wish me luck.

Mylar does indeed reflect about 85% of heat, as well as up to 90-95% of light. Be careful of hot spots both on your plants and behind the mylar. Make sure to install it flush with the surface. Good luck!

 

[Alex420]

I"m planning on using some 60 mil white PVC roofing material with a reflective index of 0.86 as a liner, any comments?

I think this is a great idea. I thought of doing the same myself with maybe some Kool Seal? It says it reflects over 90% so I can't see how you can go wrong with

 

[TorturedSoul]

I would strongly recommend against using mirrors.

Me too. I hope I did not give the impression that I favored them, lol.

 

[onewarmguy]

Download the technical data sheet and check the specs. Keep in mind that there are two areas that show reflectivity one is the Solar Reflective Index (SRI) that reflects how much heat gain is reflected back into the atmosphere, the other is the reflectivity rating. I checked KST Coatings website for you, they're a division of Sherwin Williams and they do not show that information. The MSDS sheet makes for interesting reading though, I'd highly recommend you take a look at it before proceeding apparently one of the ingredients is a known carcinogen!

 

[marijunal]

i didnt try but emergency blanket looks very usefull and very cheap

 

[garylee]

I lot of cool ideas here but I have always headed to home depot or Lowes and picked up some KILZ paint. Its a white primer which already has anti fungus, mold, and bacteria mixed right in. Goes on easy and has always worked great for all of my grow rooms over the years.

 

[caligrowngasb]

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