best color to paint marijuana grow room

Best color to paint marijuana grow room

Compare Grow Room Wall Coverings: Mylar vs. White Paint vs. Vinyl GrowWall™

  • By Haley Thomann
  • Leave a comment

When choosing the best wall covering for cannabis grow rooms, technology has come a long way. Light reflectivity, ease of installation and maintenance, and budget will all be important factors in your final decision. We hope this simple comparison between three of the more popular greenhouse wall coverings will help you determine what’s best for your individual indoor grow room setup.

White Paint

Flat or matte paint is probably one of the most affordable grow room wall options. It is extremely economical if you have a large grow facility to cover. Cannabis growers will steer you away from using high-gloss paint because it may create grow room hot spots. But, white is always the preferred choice for any grow room wall covering because white reflects light better than metallic colored or silver wall covering. Flat white paint has the ability to reflect between 75-85% of your indoor lighting source. You won’t get pockets or bubbles with paint, so you won’t see problems with hot spots either.

Although paint’s greatest advantage is price, it lacks many characteristics that can enhance grow room productivity. Other than reflectivity, paint does not aide in insulating or cooling your growroom. Organic cannabis and medicinal marijuana require sterile growing spaces. Even though paint is easy to clean, it still collects debris on its surface. It is recommended you add a fungicide when painting which will increase the cost of the overall project.

Maybe the biggest downfall to paint is the labor, and once completed, paint is one of the most permanent greenhouse coverings. You need rollers, brushes and other supplies for a paint project and at least two coats for full coverage. It will take a few days for complete drying and to rid your indoor grow room of any crop damaging fumes.


Developed by NASA, Mylar is a synthetic, reflective, shiny, silver greenhouse covering available in sheets and rolls. Pricing for thin Mylar films has gone down in recent years and more durable, thicker versions, such as Foylon, have stormed onto the greenhouse products market. Foylon is spun polyester fabric more resistant to tearing and is easier to clean. Indoor cannabis growers like Mylar’s ability to reflect light anywhere from 90-98%. Good grow room ventilation is necessary if using Mylar.

Mylar does pick up dirt decreasing its ability to reflect light. When it comes time to clean, Mylar grow room wall coverings must be taken down to wash. If installed using tape, that can create problems with tearing and creasing. Even if using Velcro to adhere to walls, it is tough to avoid rips and folds. Mylar usually needs replacement after only a few grows.

When installing Mylar film, it is imperative the film remains completely flat. If not, bumps, bubbles and air pockets form causing hot spots in the grow room and reduced reflectivity. As long as Mylar sheets aren’t damaged they are reusable.

Mylar is not completely light proof or airtight, so it does not aide in growing cannabis organically or producing a more potent marijuana plant.

GrowWall™ Wall Coverings for Grow Rooms and Greenhouses

Groundbreaking GrowWall™ is a premium, solid polyvinyl greenhouse product manufactured in the USA by Better Life Technology, the makers of G-Floor® Universal Flooring, AquaTread® Marine Flooring and BILD™ Print Media vinyl graphic flooring and wall coverings. GrowWall’s premium polyvinyl engineering makes it one of the most durable, low maintenance grow room wall coverings available. It may not be the cheapest option, but with an array of growing benefits that actually enhance the cannabis bud and yield, GrowWall provides cannabis growers excellent value.

Constructed of 35 mil thick 100% polyvinyl in Absolute White, GrowWall’s ceramic texture and ultra-reflective top coat has proven to reflect light over 400% more than traditional greenhouse coverings, including Mylar and paint. This advanced top coat reduces glare, hot spots, and resists UV-rays, helping distribute lighting more evenly throughout the growing space.

In addition, waterproof GrowWall resists mold and mildew and helps create a lab-like growing environment without microbes and bacteria. Its white surface also aides in spotting harmful bugs and debris. GrowWall’s vinyl qualities make it less prone to tears, scratches, peeling and curling; GrowWall lasts grow after grow without deterioration and replacement.

GrowWall is available in rolls of 4.5’ x 10’ and 6’ x10’; simply trim to fit any grow room space. Panels with PSA backing are also available. No need to take GrowWall down to clean; just hose down or wipe with water and/or mild detergent.

And last but not least, GrowWall is eco-friendly; it is repositionable, reusable and recyclable. It insulates your grow room and reduces greenhouse cooling costs, too.

When choosing the best wall covering for cannabis grow rooms, technology has come a long way. Light reflectivity, ease of installation and maintenance, and budget will all be important factors in your final decision. We hope this simple comparison between three of the more popular greenhouse wall coverings will help yo

Reflection – Increase Yields Indoors with Reflective Walls

Light Reflectivity in the Cannabis Grow Room – Make the Most of Your Grow Lights!

Introduction to Reflectivity

It’s important for any grower who is cultivating cannabis indoors to maximize on the power of their grow lights. Indoor cannabis grow lights have gotten insanely bright over the years and this has enabled growers to provide their plants with an abundance of light. However, you can make your grow lights seem even brighter and more powerful without actually increasing the amount of electricity you use. Proper reflection of the walls near your cannabis plants, and a great hood/reflector will bounce the light from your indoor grow lights back at your plants instead of letting all the light that hits the sides be absorbed.

In fact, proper reflection can get up to 30% more light to your cannabis plants! This is all without changing anything else about your setup. No extra electricity, just 30% more light!

As you probably know, light is what cannabis (and most plants) use to make energy and light is what powers the growth of your buds.

It’s important to understand that indoor cannabis grow lights are most effective when you get as much of the light they produce to your plants as possible. The further light has to travel to your cannabis plants, the more light that gets “lost” on the way. By making sure light is reflected back at your plants, your plants get to use even more of the light that gets produced which would normally be “lost”. Reflective walls will also help prevent parts of your plants from sitting in a dark or shadowy spots.

Outdoors, growers get to use the sun! The sun is almost 93 million miles away, but it produces so much light that very little light is lost over small distances. That means reflectivity isn’t important when growing outdoors in direct sunlight; the sun already gives your plants all the light they need!

Unlike growing outside, reflectivity is important to get the biggest yields indoors!

More light = faster growth & bigger yields!
…but only up to a certain point!

Today I will guide you through the most effective ways to get more light to your cannabis via reflection!

The walls of your grow area:

Your plants will get more light if they are in a contained space with reflective walls compared to plants sitting in the middle of an open room, even if the walls of the room are reflective. This is because the amount of usable light a wall can reflect to a plant diminishes as the wall gets further away.

This is partly why grow tents and grow boxes are so effective – in addition to helping you provide the perfect environment to your plants, they help contain the light so your plants get more of it!

Make sure reflective walls are set up to achieve the greatest reflectivity! This means:

Avoid creases/wrinkles in materials that should lay flat

Walls should be flat with as few bends or turns as possible

Smooth curves are better than 90° bends in the shape of the reflective coating

Hammered style texture provides some of the best reflection because of the angles at which it reflects light and it cuts down on hot spots. Most professionally made grow tents have a hammered style reflective material on the wall. This hammered finish is also what you find in high-quality light reflectors.

Reflective material is not dirty or discolored – keep your walls clean!

Note: When covering the walls with something that comes in a flat roll like mylar or foylon, make sure the material is placed flat against the wall to avoid air bubbles which can create hot spots and reduce reflectivity. Velcro is a great way to place up reflective materials with minimal creasing or tearing.

The BEST reflection comes from “hammer style” texture, like the walls of professional grow tents and light reflectors. We’ll go into detail about other options, but if you’re looking for the straight up answer, there it is!

Reflectivity Options for Your Cannabis Grow Room

Different reflectivity options vary in their efficiency. It’s also important to find a solution that fits your personal setup and budget. I will cover some of the most popular options – along with the pros and cons of each one – to help you pick the right option for your cannabis grow room.

Highly Recommended Reflectivity Options for Your Grow Area

Grow tent walls (best reflectivity)

Getting a grow tent will give hobbyist cannabis growers probably the best light reflectivity of any option. Grow tent walls are easy to clean, light proof, water resistant, won’t melt (like some plastics) and most grow tents are created with built-in cooling options. When it comes to growing personal amounts of cannabis indoors, grow tents are one of the best options for your grow area “walls” as they have been designed over several decades to create the best indoor grow environment for your plants. Grow tents can be found in many sizes, and generally will give you the best results for your money. After I got my first grow tent, I realized I could never go back to growing in anything else!

Flat white latex paint (85-95% light reflectivity)

This is a highly recommended option for those who can’t invest in a grow tent or for the crafty DIY grower who opts to build a grow cabinet (or a whole room). Excluding the hammered style texture you see in grow tents, this paint will give you some of the best “bang for your buck” of any reflection option. Flat white paint is inexpensive, effective, and there’s no way to create air pockets or hot spots behind the reflective material. Just paint the walls, let them dry, and you’re done!

White paint absorbs a lot of heat without reflecting it back into the room (which would require more venting to keep heat down) and painted walls are easy to clean. Do not get glossy paint even though it seems like it would be more reflective – you want flat (called ‘matte’) white paint for the greatest reflectivity. If you have the option, you can paint the ceiling and/or floor for even greater reflectivity. Sometimes paint containers will list the reflectivity, and the more reflectivity, the better.

Panda Plastic (85-95% light reflectivity)

Panda plastic (also known as “Black and White Polymer”) gets its name from being white on one side and black on the other. Although it can be a bit expensive, panda plastic provides great light reflectivity. You point the white side towards the lights, and the black side will help trap light from getting in or out. Panda plastic can be nailed or otherwise attached (velcro works great) to your walls and is easily taken down. The thicker the panda plastic, the more durable it is. Remember, this is made of plastic, so it can melt if it gets too hot – be careful to never let Panda Plastic sit too close to your lights!

Orca Grow Film – (90-94% light reflectivity)

Orca grow film is made of white plastic microfiber and uses a unique structure that is similar to snowflakes or the skin of orcas (killer whales) to scatter light. Although expensive (even more so than panda film), Orca grow film is mold-resistant, easy to clean and thick – these features make it more durable and less likely to tear compared to some other reflectivity options. Using a highly reflective crystalline structure, Orca grow film evenly distributes reflected light so it doesn’t tend to create hot spots even when it has some creases. Orca film is used like panda film in that you point the white side at your plants with the black side facing outwards. Orca grow film tends to reflect back infrared light as well, which means it will tend to keep heat inside the grow room. Good for areas where the temperature gets low.

Good Reflectivity Options

Kool Seal White Elastomeric Roof Coating (90% reflectivity)

This is another option than can be quite expensive though it gets the job done. White elastomeric roof coating is a great option for some growers; it’s made of 100% acrylic elastomeric resin and sticks to almost any surface.

Once dried, it forms a thick blanket of mold-resistant protection that expands and contracts like rubber and will tend to keep heat inside the grow area (good for cold regions) and it even helps absorb sound.

The biggest drawback to this method is the cost. It’s recommended that you use a primer like Kool Seal Kool Lastik Primer in order to make sure the coating sticks properly to your walls, however, this only makes the price that much more unappealing.

Mylar (90-95% light reflectivity)

Mylar is an inexpensive reflective material that looks shiny and usually comes in sheets or rolls. “Foylon” is a more durable version of mylar and “C3 anti-detection film” is an infrared-proof version of mylar (which means it contains more heat). Mylar generally is offered in 1mm or 2mm thickness – the thicker the mylar, the more durable it tends to be (resistant to tearing or creasing).

Mylar can be difficult to clean and may need to be replaced after a few grows. It is not light-proof, but does help contain heat in the grow room, so it’s important you create a good ventilation system to get rid of all the extra heat that’s being contained in the grow area. If there are creases, tears, or the film gets dirty, the light reflectivity is dramatically reduced, so make sure it’s placed flat on the walls and kept clean.

“Just Okay” Reflectivity Options

White Poster Board (up to 60% light reflectivity)

White poster board is inexpensive and readily available. Some growers will use it around the edges of the grow room, as well as for the floor and ceiling. While it is reflective when new, white poster board is difficult to clean and gets soft and/or moldy if it gets wet.

Aluminum foil (55-60% light reflectivity)

Aluminum foil (also known as tin foil) is often used in the kitchen, and many growers will see that it’s shiny and deduce that it may be a good option to reflect light back at your cannabis plants. Despite what seems intuitive, the dull side of aluminum foil actually reflects light better than the shiny side. Unfortunately, one of the problems with aluminum foil is that it’s extremely easy to crease, and any uneven creasing can dramatically reduce the reflectivity. In fact, anyone who has used aluminum foil knows that it’s a challenge to not crease it! Some growers will crinkle all the aluminum foil, which can help diffuse the light more evenly. Having everything creased all over actually works better than laying it flat with just a few creases. Aluminum foil will not burn your plants like some growers claim, but there are much better reflective options out there and foil should only be used as a last resort before replacing it with something else.

Emergency blankets (70% light reflectivity)

Emergency blankets are usually made of mylar, but they tend to come folded up instead of in a roll (making them easy to crease). These blankets tend to be very thin and easy to tear by accident. One of the advantages is these blankets are cheap so can be replaced often, but it is difficult to get them to lay flat against your walls.

“Do Not Use” Reflectivity Options

Mirrors (good reflectivity for images but not for light…)

Mirrors seem intuitively like a great choice, but in reality they are “just okay” (at best) for reflecting the light of indoor grow lights back at your plants. While mirrors are great at clearly reflecting your image back at you, they’re not meant for reflecting light; especially light that is actually usable to your cannabis plants. Mirrors don’t reflect light from the grow lights in optimal patterns and tend to create light/heat spots. While better than a black wall, I strongly recommend not using mirrors for reflection in the cannabis grow area.

Styrofoam (60-70% reflectivity)

Styrofoam (Expanded Polystyrene Foam) is cheap, can be purchased in sheets, is durable and doesn’t weigh much at all. You can hang them on the walls, or styrofoam sheets can even be used as a “wall” all by itself. The uneven surface of styrofoam helps diffuse light without creating hot spots. However, the pros of styrofoam are outweighed by the fact that it’s super flammable! For that reason alone, I strongly recommend not using styrofoam for reflection in the cannabis grow area.

How Reflectivity Affects Temperature in the Grow Room

Certain reflectivity options tend to hold heat in, while others tend to let heat out. Which do you need for your grow setup?

If your grow room is cold…

Use one of the following recommended options to reflect back heat in the grow room…

Kool Seal White Elastomeric Roof Coating

Mylar / Foylon / C3 Anti-Detection film / Emergency blankets

Aluminum foil (in a pinch – this is not a great long-term option)

Or just get a grow tent, which will contain much of the heat unless you vent it out.

If your grow room is hot…

Use one of the following recommended options to easily let heat escape the grow room…

Use flat white paint on the walls of your grow space to reflect back a lot of light, while absorbing some of the heat.

Paradoxically, a grow tent is also the best option for hot grow areas because they come with built-in cooling options that make it easy to set up an exhaust and gain complete control over the temperature of your grow area.


Look for reflectors where the inside has a “hammer style” surface texture, as this is the most effective at reflection

Look for smooth curves in your reflector/hood if possible. More sharp bends in the reflector will slightly reduce its efficiency.

Opt for a wide reflector above your plants. Narrow or small reflectors aren’t able to bounce back as much light down at your plants. This is why small “cool tube” reflectors have limited reflection abilities compared to other types of hoods with broader faces.

Reflectors should be close to your bulb and reflect light downwards at your plants

Light Meters

While the above guides will help you get the most from your grow area, one of the best ways to actually test the amount of light your plants receive is to use a light meter (also known as a lux meter).

A light meter actually measures how much light is being received at a particular spot. You can use one to actually measure how much your reflective walls are making a difference to your plans! Note: While light meters are pretty good for measuring the light from most grow lights, they are not as effective at measuring light from LED grow lights.

The Science: Often you’ll see light bulbs measured in how many “lumens” are given off. For example, let’s say a bulb produces 20,000 lumens – how do you determine how much of that light is actually being received by your plants? A light meter measures “lux,” which is different from lumens, and lux is a better indicator of the amount of light received by your plants. Lux measures how many lumens are received in a specified amount of area (a lux is equal to one lumen per square meter).

This is what’s important to your cannabis – how much light is actually getting to your plants! Many factors will affect how many of those lumens actually “make it” to your plants such as how far the plants are from the lights and the reflectivity of your walls. While lux isn’t a perfect way to measure light, it’s better than using lumens.

Analogy: “Lumens” are like the advertised horsepower of your car. “Lux” is like the actual top speed of your car.

It’s important to understand that a light meter measures the total amount of viewable light, and doesn’t measure the “spectrum” of light. A light meter can’t tell whether the light is in the spectrum that your plants prefer or can use. This is why it’s important to get grow lights made for plants like cannabis, so you don’t have to worry about spectrum.

A light meter will measure the amount of “lux” and here’s a good guide to help you determine if your plants are getting enough lux.

85,000 lux – at this light intensity, you’ve hit the plant’s “saturation point” which means your plant can’t use all the light (be careful of light bleaching!)

Note: The only way to increase the plant’s saturation point is to supplement with CO2.

Light meters will let you directly measure the change in brightness as you add reflective materials to your grow area, as well as adjust your lights so they are closer or further away from your plants to provide the precise amount of light you want.

Light meters are also useful for testing new or old grow lights to make sure the bulbs are as bright as they should be. As grow lights get older, they tend to produce less light over time, and a light meter can help you decide when it’s time to change your bulbs or upgrade your grow lights.

Conclusion: Best Indoor Reflectivity Option

Hands-down your best option for small-scale growers (if you can afford it) is to get a grow tent which is specially made for growing plants.

Get a professional grow tent with “hammer-style” textured walls if at all possible.

Grow tent walls are designed to reflect back the most light that is usable by your plants, and have reflective materials on all sides including the floor and ceiling.

Quality grow tents are light proof (no light gets in or out) and are designed to be hooked up to an exhaust system to easily control your heat. They are also water resistant and easy to clean. A grow tent is easier to set up and use than almost any other grow option.

Gorilla Grow Tent Lite 4 x 4
This is a very popular, well rated and widely used tent among hobbyist growers. This tent will help you grow sticky homegrown for years to come!

What do you cover the walls of your grow room with to reflect the most light at your plants?