What is Supplemental Lighting in a Growroom?

By Kent Gruetzmacher
Published: January 23, 2023
Presented by AC Infinity Inc.
Key Takeaways

Supplemental lighting can take your grow from just average to awesome. Kent Gruetzmacher explains how and why adding additional light can make a huge difference in your cannabis yields.

If you’re looking to consistently produce large yields, getting your lighting grid properly balanced is critical. Nonetheless, with so many good grow lights on the market today, it can be tough to discern which technologies are best suited for your needs. To protect against potential inefficiencies, some growers opt to use supplemental lighting.

While horticultural lighting technology has grown leaps and bounds in recent years, no lighting schematic is perfect. Whether a grow light lacks certain wavelengths or falls short illuminating parts of your canopy, such inefficiencies can negatively impact your yield.

Horticultural equipment manufacturers engineered supplemental lighting to enhance your primary lights can cover any potential shortcomings.


Growrooms vs Greenhouses

There is a big difference between the supplemental lighting used in growrooms versus that being implemented in greenhouses.

While all greenhouse growers depend on sunlight as their primary light source, many also add grow lights which they refer to as “supplemental lighting.” In these situations, growers utilize lights like 1,000W DE HPS fixtures that help illuminate the garden when it is cloudy outside. Some greenhouse growers also use artificial lighting to extend photoperiods so cannabis plants aren’t triggered into flowering.

For indoor growers, supplemental lighting is used to enhance the coverage already provided by your primary lighting grid. Since the function of supplemental lighting is to fill small voids in your canopy, these fixtures are designed as long, thin strips of lights. In turn, supplemental lighting strips are generally hung between the primary fixtures of your grid or walls on the outside of your canopy.

Enhanced Light Coverage

cannabis growing under artificial light in a growroomBy adding supplemental lighting to the walls, you can grow flowers in regions of your garden that you previously didn’t think possible.


One of the biggest selling points of supplemental lighting is the enhancement of overall light coverage. No matter how efficiently you design your lighting grid, there will likely be dark spots on the sides of your garden canopy. However, since the center of your lighting grid is likely maxed out with usable PAR light, adding more full-strength lights will burn foliage and waste electricity.

Many growers don’t consider the fact that plants on the edge of your canopy can produce good yields. As such, it is common practice to clean-up the branches and fan leaves on the outer rows of gardens. However, by adding supplemental lighting to the walls, you can grow flowers in regions of your garden that you previously didn’t think possible.

In instances where growers use weaker fixtures such as 600W HPS lights as their primary sources, it might also be beneficial to supplement darker areas between rows of lights. If you decide to go this route, just be sure you don’t overload your canopy with too much light.

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Augmented Wavelengths

Another popular use for supplemental lighting is to augment your primary lights with colors that are lacking in your current setup. While many of today’s most popular LED grow lights do a great job with both vegetative growth and flowering, HPS and MH lights lack certain important colors of the light spectrum.

HPS lights are used for flowering because they provide a red spectrum that mimics the color of sunlight in the late summer and fall. While HPS lights are great for growing huge buds, they aren’t the best for stimulating chlorophyll production which is so important during earlier growth phases.

If you are growing with HPS lights and don’t want to set up a dedicated veg room with MH lights, supplemental lighting might be the way to go. By adding a few lighting strips, you can augment your primary HPS grid with more blue light. In turn, this increases the versatility of your growroom or tent.

What Types of Lights are Used for Supplemental Lighting?

cannabis growing under artificial light in a growroomLEDs and fluorescents are the two key technologies are used for supplemental lighting today.


LED Lights

It can’t be denied that LED grow lights have taken the cannabis industry by storm. In fact, many people feel LED lights are the way of the future and it’s only a matter of time before older models are outdated and replaced. Following this important trend, LEDs are also immensely popular for supplemental lighting.

Equipment manufacturer AC Infinity recently came out with their own line of supplemental lights with their Ionbeam Series. Sold in kits, the Ionbeam Series setups include a lighting controller, four LED grow light bars, and four steel bars that enable flexible mounting on any surface in grow tents and growrooms.

Fluorescent Lights

Fluorescent lights have been around longer than just about any type grow light on the market. While they are not strong enough to stimulate flower growth in cannabis plants, many people still use fluorescent lights for seedlings. Since they are not very strong, fluorescent lights also make an interesting option for supplemental lighting.

Due to their long, slender shape, T5 fluorescent light strips can be easily hung along walls or between primary lights. Moreover, since certain T5 models emit and blue and white light, they make great supplemental HPS lighting setups. Finally, since fluorescent lights are inexpensive, they are a good option for growers still experimenting with supplemental lighting.

While the horticultural lighting industry has expanded exponentially in recent years, there is still room for improvement. Even more, with such limited space available in indoor gardens, it only makes sense to look at different areas of your growroom for expanding production. While the top of your canopy is an obvious place to focus your attention, growing flowers on the sides is also an interesting prospect.

Since the goal of any indoor grower is to produce as much cannabis as possible per square foot, any trick that bolsters production should be considered. While many growers are slow to adopt supplemental lighting, it just might be the ticket for finally crossing that 2 lb. per light threshold.

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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