What is the Best Material for Growroom Walls?

By Kent Gruetzmacher
Published: July 11, 2022
Presented by AC Infinity Inc.
Key Takeaways

Wondering if a certain material is best to use for your growroom walls? Kent Gruetzmacher explores several materials and gives the scoop on which is best for your growroom.

As all cannabis growers are well aware, electricity is by far the largest operating expense for any indoor garden. Whether you have a small personal grow or a large commercial operation, you have to consider energy usage every step of the way.


Setting up your growroom in a way that maximizes the energy emitted from your grow lights is critical in getting the largest return for electrical expenses. As such, since the early days of indoor growing, cannabis cultivators have worked to figure out what materials best reflect light off growroom walls.

By using the right type of material on your growroom walls, you will ensure that light is adequately reflected and evenly mixed around the garden canopy. Importantly, reflective material will also help keep you from wasting electricity with light spilled onto absorbent surfaces.


Why Do Growroom Walls Need Reflective Material?

When grow lights are operational, they emit photons in a conical shape as light makes its way to the garden canopy. It’s important to note, the light in the middle of the cone is much stronger than that on the peripheries. If any of this light hits a non-reflective surface, it is absorbed rather than being reflected and utilized by plants for photosynthesis.

Inverse-Square Law

If you have spent any time designing indoor gardens, there is no doubt that you have heard the term “inverse-square law.” NASA explains, with the inverse square law. energy twice the distance from a light “passes through 4 times the area that it did at [half] the closer distance, so its brightness is 4 times fainter.”

As light travels from grow lights, it spreads out while reducing in intensity before reaching the garden canopy. Because the reduction of light intensity is exponential with the inverse-square law, its critical to get the distance right between a grow light and canopy.


To makeup for the loss of light intensity due the inverse-square law, growers design horticultural lighting in rows. By running fixtures parallel to one another, periphery light from multiple sources intermingles and creates uninform coverage on the canopy.

Importantly, cultivators also use reflective material on walls to catch periphery light and bounce it back into the room.


Without the proper materials on your growroom walls, you run the risk of wasting all the periphery light on the edges of your garden.

shadow of a cannabis plant on a white wallWhite paint will reflect around 80 percent of your light source.

White Paint

White paint is one of the most affordable materials for covering growroom walls. Please note, high gloss and metallic paints are known to cause hot spots with grow lights. As such, these reflective paints should be avoided if you want even light coverage in your garden.

In the end, basic, flat white paint works the best for reflecting light. In fact, white paint will reflect around 80 percent of your light source, making it quite effective considering its cost. Painted walls are also easy to care for, as well as keep clean.
Because flat white paint is extremely affordable compared to materials like panda film, it is a great option for commercial growers.

Panda Film

Panda film is an immensely popular growroom wall material. Panda film is a poly film that is colored white on one side and black on the other – this coloration gives the material its name. AC Infinity makes a high-quality panda film with multiple uses. The white side is great for reflecting light in growrooms while the black side is used to block sunlight in light deprivation greenhouses.

AC Infinity’s Panda Film does a great job of reflecting usable PAR light with 90 percent reflectivity.

Quality panda films can be stretched without tearing and can hold up to the environmental rigors of growrooms. Panda film is waterproof and easy to clean, so it does a great job of protecting walls from such things as spills and sprays.

cannabis in a growroom with mylar wallsMost grow tent manufacturers opt to line their tents with Mylar.


Mylar is a space-age material that was originally created by NASA. Mylar features a highly reflective silver surface and is sold in rolls similar to panda film. With reflectivity up to 98 percent, Mylar is the most reflective material used on growroom walls today. For this reason, most grow tent manufacturers opt to line their tents with Mylar.

Mylar is also an attractive option for covering growroom walls because it is a great insulator. Whether you are trying to heat or cool your growroom, better insulation gives you greater control over the growroom environment. A well-insulated room will also be far cheaper to cool during the hot summer months than a non-insulated room.

As far as pricing is concerned, Mylar is about equal to panda film. However, growers do report that Mylar easily loses its reflectivity when dirty or scuffed up. Also, if air bubbles form beneath Mylar, they can cause light hot spots on your growroom canopy.

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To grow quality cannabis, you need to pay careful attention to the growroom design phase. Beyond being good for plants, making educated decisions on things like material for growroom walls can save you money when your garden is operational. Remember, since your grow lights will be running every day, the efficient use of light is the most surefire way to maximize your return on electricity bills.

Looking at white paint, panda film, and Mylar, it seems that each material is applicable in certain scenarios. For example, panda film is a great option for home growers with custom-built rooms, but it is not as practical in commercial settings. When it comes to prepping massive warehouses for cultivation, white paint is likely the best choice. In addition, Mylar seems to be the best option for grow tents as it can be integrated with fabric.

Whatever the size and scope of your indoor garden, there is a material to cover your walls that matches your needs.

AC Infinity logo

AC Infinity is the foremost name in air delivery systems, designing and developing the latest innovations in cooling and ventilation technology. They offer a suite of quiet inline fans that automate the growing progress and track key metrics. Visit or contact [email protected] to learn more.


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Written by Kent Gruetzmacher | Writer, Owner of KCG Content

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Kent Gruetzmacher MFA is a Colorado-based writer and owner of the writing and marketing firm KCG Content. Kent has been working in the cannabis and hydroponics space for over a decade. Beginning in California in 2009, he has held positions in cultivation, operations, marketing, and business development. Looking specifically to writing, Kent has worked with many of the leading publications and marketing agencies in the cannabis space. His writing has been recognized by such icons as Steve D’Angelo and Rick Simpson.

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