Best Reflective Materials to Grow Indoor Cannabis

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Added 26 May 2022

Imagine watering your plant with incredible nutrient solutions, with almost 30% going to waste. Doesn't sound too good, huh?

Then, why should you let 30% of your light go to waste?

If you are growing cannabis indoors, you'd be surprised to know how much of your light is getting wasted, not to mention the electricity bills. Regardless of how expensive your lighting setup is, it emits light in the form of waves. 

The middle portion of the wave falls on your plant's canopy, but the periphery light falls on the walls, floors, or doors and gets wasted if it hits a light-absorbant surface.

However, you can salvage this wasted light with some reflective materials. Reflective materials do exactly what they sound like — they bounce the light emitted from the light panels back towards your plant, where it is needed the most. 

And by optimizing your lights by up to 30%, without using more lights or energy, you can improve your plant's photosynthesis process and expect better growth and larger yields.

Learn more about the best (and the worst) reflective materials you can use to optimize light in your grow room. And, of course, you'll find some tips that help.  

The Best Reflective Materials to Grow Cannabis Indoors

If you want to save the wasted light, you need to invest in the right equipment. Fortunately, modern technology has you covered with many options — some are expensive, and others are more bang for your buck. Here are some of the best reflective materials you can try out in your grow room.

Mylar Film


Perhaps the most popular reflective material in the cannabis community is mylar film. It is a thin polyester film that is highly reflective and can reflect up to 97% light back to your plant's leaves. 

You can purchase these films from online stores or your local gardening store in different thicknesses, although the most common thicknesses you'll find are 1 mm and 2 mm. 

If you use mylar film to optimize light in your grow room, ensure you have proper ventilation. Mylar tends to reflect the radiant heat energy that can increase the temperature in your grow room.

Another downside of mylar is that it is quite a delicate material and is easy to tear or crease. So, you must also be very cautious when applying or cleaning it.

Foylon Film


If you like mylar but want something better, consider using a foylon film. A resilient version of mylar, it's made from spun polyester reinforced with foil-laminate.

The advantage it offers over mylar film is that it is not so easy to tear or crease and is resistant to most solutions, so you can also clean it easily. Plus, it does not fade as much as mylar over months of use. 

The only downside of foylon film is that it is expensive. But the extra cost is worth it.

Panda Film

panda film

Panda film is another terrific solution to optimize light within your grow room as it can reflect as much as 85% to 95% of light. Many growers use this to cover their grow rooms and greenhouses, so it has a reliable reputation.

The name gives it away — panda film is black on one side and white on the other. And since it is made from co-extruded polyethylene, it is also waterproof and durable. 

To place it in your grow room, position the panda film with the white side towards the light and use some duct tape or a staple gun to hoist it. You can also place this on your grow medium with the black time facing the substrate. Doing so stops the light from reaching the medium, preventing algae and weed growth.

Panda films are easy to purchase online and sell roughly for 25€ for a 20 x 2 m roll.

Orca Film

orca film

Like panda film, orca film is another reflective material with one white and one black side. However, it has some advantages over the panda film.

Orca film features white plastic microfibers on the surface that offer better reflectivity, 90% to 95%, and light scattering. In addition, the same microfibers make it more durable and less prone to creasing or tearing.

And orca film is more mold resistant and easier to clean than panda film. 

But these advantages come at a higher price tag of around 95€ to 100€ for a 10 x 1.4 m roll.

Flat White Latex Paint

white paint

If you are looking for a cheaper and more durable solution, you can choose a flat white latex paint. It is the best option for a big grow room as it can reflect up to 75% to 85% light. 

And unlike mylar, it is less prone to create light hotspots in your garden. White paint also absorbs a lot of heat, so you don't have to worry about a temperature hike. 

Your white paint can also be super easy to clean depending on the brand — a damp cloth is all you need for some easy-to-clean white paints.

Although, avoid glossy white paints as they don't reflect as much light. Matte latex paints are the best for this job. You can also check out elastomer paints as they offer high light reflectivity of up to 90%, and they are also more mold resistant.

Flat white paint is a terrific choice as you only have to apply it once to your grow room and forget about it. And it's a fun DIY process!

Emergency Blankets

emergency blanket

You probably wouldn't expect a survival gear to help grow your plant, but they might just pull out a surprise!

These emergency blankets feature a reflective surface intended to keep injured hikers alive by trapping 90% of their body heat within so that they can fight the cold. However, the same lining is also quite good at reflecting light.

Emergency blankets offer 60% to 70% light reflectivity since they are made of mylar. Most emergency blankets are around 210 cm x 130 cm (may vary among brands), and you can use duct tape or double-sided adhesive strips to hoist them in your grow room. 

Aluminum Foil

aluminium foil

Lastly, you can choose aluminum foil. It is not the best option since it only offers 55% to 60% light reflectivity, but it gets the job done in a pinch if you only want to cover a small area. And it is super cheap to buy.

To apply aluminum foil to your grow room, use the dull side as it is more reflective than the shiny side. And use duct tape to apply it, but be careful not to crinkle or tear the foil as it can defeat the purpose. 

Materials to Avoid in Your Grow Room

The materials mentioned above are terrific for salvaging wasted light in your grow room, but you might also come across a few materials on the internet. However, they are not the best option, and you must avoid them. Here are a couple of materials that you should avoid.



But mirrors reflect the light in high definition, don't they? Wrong. Mirrors only reflect images, and the light they reflect is not in the correct pattern or intensity to make a difference to your plant. 

Also, mirrors tend to create various light and heat spots around the grow room, which can cause light burns on some leaves of your plant.

Mirrors are okay at best in optimizing your grow room's light and should be avoided.



Many filmmakers use styrofoam for indirect lighting on the set because it has a decent reflectivity of around 75% to 85%. But while using it on a film set may be safe, the same can't be said for indoor gardens. 

The advantages of styrofoam are shadowed by one major disadvantage — it is highly flammable. Under the intense light and electrical systems, a single spark can lead to a flame in your grow room. So, it is best to avoid styrofoam entirely. The risk is not worth it.

Tips on Using These Reflective Materials

Whichever material you use, there are a few things to keep in mind to avoid mistakes and unintended light leaks. Follow the tips below:

  • Avoid creases and bubbles when installing the materials, as they can create bright or dark spots in your garden which are not suitable for the plant. And they can also reflect light in the wrong direction.
  • Don't just cover the walls. You must also cover the doors, windows, and other openings and corners to minimize the loss of light.
  • Invest in a lux meter that measures the amount of light on a particular spot.
  • Keep the materials clean and well-maintained. Otherwise, they may get discolored, covered in grime, or grow mold. All you have to do is wipe them down with some isopropyl alcohol or hydrogen peroxide.
  • Know which material is right for you as some materials trap heat inside while others reflect the heat. For a cold grow room, use orca or panda film, mylar, or emergency blankets, and for a hot grow room, flat white paint works best.

Summary: Best Reflective Materials to Grow Indoor Cannabis

Investing in expensive light setups won't benefit your plant if 30% of the light is lost to other surfaces. That is not only a waste of light but also energy. So instead, invest in reflective materials listed above to salvage the light.

And avoid solutions like mirrors or styrofoam. They are mainly ineffective and, in some cases, dangerous for your grow room.

See which material fits your preferences and budget, and order it now. 



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The distance reflected light has to travel determines it's intensity. Light traveling to a wall and finally reflected back to plants is about as strong as a dollar store flash light . A good reflective material with a black backing is for containing the light . Which is important for keeping a low profile . I use mylar coated thin insulation used under hardwood floors. It's about 3 mm thick . Doesn't crease . Very easy to install. In Canada a 4 foot by 25 foot roll is about 50 $ . In Canada all electrical appliances including led lights are url approved . I would suggest ensuring all your electrical equipment is properly rated to be safe . One inch styrofoam 4 by 8 sheets is one of my favorite walls for large legacy grows . Not that I do that any more . Par readings at canopy level is the only place light measurements should be taken. I really wish this point was emphasized. A good reflector for a. HPS or a HID light does make a significant difference in light intensity. Sorry but reflected light off of walls is too low to be of any use. Light loss is a root square equation . Example . 1000 lumens at 12 inches is 500 lumens at 24 inches . Yes I measure lumens because we see in the exact wavelength s as plants need to grow .
Aluminum foil is shown to be up there with mylar. Here's a split-test showing that it even outperforms mylar and others: Do the results in this list show any PPFD readout comparisons?