Considerations to Make When Designing Horticultural Lighting

The indoor gardening industry consistently evolves with the technology that supports it. While advancements in cultivation technology and methodology are doubtlessly exciting, the sheer number of hydroponics products on the market today proves quite intimidating. This vast amount of product choices has profound effects on grow room design. Perhaps no segment of the indoor gardening field has seen the sort of change and innovation as horticultural lighting.

horticultural lighting

The lighting marketplace is the most volatile seen in the hydroponics product space. To illustrate, the inclusion of LED lights within indoor growing has begun to alter the way in which cannabis cultivation operations are designed and operated. In a similar vein, and some years ago, the invention of double-ended (DE) HPS lighting had a similar paradigm-shifting effect. For reasons such as these, the rapid influx of changing horticultural lighting technologies on the market proves both confusing and intimidating for all levels of growers, from novice to expert. This same notion applies greenhouse operations, CEA businesses, and cannabis grows.

When designing a grow room, its all-to-easy to become overwhelmed with the complexities of horticultural lighting schematics. The same can be said about the sales pitches and marketing gimmicks of lighting companies. Unfortunately, both scenarios often lead to illogical, impulse buys on the parts of growers. That being said, for those looking to design lighting systems for an indoor garden, a logical point of departure in the planning process is the grow room itself. All things considered, following these simple criteria will help the careful agronomist avoid impulse buys and plan logically.

Initial Cost & Energy Demands 

Perhaps the most efficient way to plan the lighting system of a grow room is to begin by considering pricing as related to initial cost versus energy demands. Weighing one’s initial overhead against the light’s intended usage, including both regularity and scale, will give one a concrete starting point in choosing the correct system.

horticultural lighting

A quick financial overview of the three primary lighting systems on the market today provides a great roadmap in making informed consumer decisions in planning a grow room. These systems are priced as such: single-ended HPS lights, DE HPS lights, and LED lights. To begin with, the traditional single-ended, air-cooled 1,000 watt grow light retails for approximately $200. Secondly, 1,000 watt DE HPS lights can be found on the shelves of hydro stores starting at around $400. Finally, ultra-modern LED lighting rigs cost about $800 for a 550 watt set-up (due to spectral efficiency a 550 watt LED light emits a similar output of usable light than that of a 1,000 watt HPS light). As can be seen, the use of LED lighting presents a far greater initial cost than seen with the first two more traditional set-ups.

The regularity and scale of usage of a cultivator’s grow room lighting directly results in the system’s energy demands, which finally translates into a power bill. With this notion in mind, growers can make sound consumer decisions regarding the purchasing of lighting equipment based on exactly how much a grower will be using said system. To illustrate, if an individual is only planning on producing one or two crops a year in a 1,000 watt grow operation, it probably makes the most economic sense to opt with an HPS system (single or double-ended). Because, the initial cost of an LED set-up will take an exorbitant amount of time to be recuperated via energy savings on such a small scale. Conversely, if the indoor gardening operation in question intends on producing five or six harvest a year, as well as ng on a commercial scale, LED’s are more than likely a more practical purchase. The regularity and scale of energy usage at this level will quickly recoup the financial overhead that comes with purchasing LED’s.

horticultural lighting

Horticultural Lighting & Infrastructure

Other important factors to consider when designing the lighting system of a grow room are the spatial and infrastructural constraints of the building in question. For most indoor gardens, the rooms in which they will be built already provide a logical road map to follow in equipment planning. As such, two crucial infrastructural elements relating to lighting design are ceiling height and air-exchange access.

The height of a grow room’s ceilings will directly influence the sort of options a cultivator has in the installation of a lighting system. For example, “Gavita style” DE HPS lights put off an immense amount of heat, yet, they don’t have options for air cooling. As such, DE HPS lights should be kept, at a minimum, 3-5 ft above the top of a garden canopy in order not to burn plant foliage. With these spatial constraints in mind, DE HPS set-ups require 12 ft ceilings for taller plant species as well as gardens that grow large plants. Therefore, indoor grows that feature ceilings under 12 ft tall will more than likely need to utilize single-ended, air-cooled HPS systems or LED lights.

One of the more easily overlooked considerations to be made when designing a grow room is how exactly the lights will affect ambient air quality in the room – this important element necessitates a planning process in itself. To illustrate, if a grower chooses to utilize an air-cooled lighting set-up in their operation, they must account for the functionality of ducting, exhaust fans, intake ports, and outtake ports. Not all infrastructures can accommodate these requirements, especially if one is building “a room inside of a room.” Moreover, if an indoor gardener opts for a DE HPS set-up, they will likely require the use of an A/C system. As such, they must consider the placement and installation of variables like copper tubing, industrial airflow, exhaust ports, and condensation hoses.


The design and build of an economically and functionally successful indoor garden is a careful balancing act of planning. While lighting systems are a crucial element to consider in the creation of an indoor grow, they are not always the most logical place to start with the planning process. With this notion in mind, one should plan their lighting system around the infrastructural options they already have available in their room. Often times, this means that growers should follow logic in planning their lighting systems, as opposed to the latest advancements and trends in horticultural lighting technology.


This article originally appeared in the July 2018 edition of Maximum Yield Magazine.