As a principal scientist at Fluence, David Hawley has spent years studying how lighting impacts plant growth, particularly in cannabis cultivation. One of the most common questions he gets from growers is about intercanopy and subcanopy lighting—two strategies that promise to optimize yields and improve bud quality. However, there's a lot of confusion surrounding these techniques. In this article, Hawley breaks down what these lighting methods really mean, the common misconceptions, and when they might (or might not) be the right solution for your grow operation.
Intecanopy vs subcanopy lighting
The definitions are straightforward: intercanopy lighting (sometimes called intracanopy lighting) refers to placing light sources within the canopy itself—amongst the branches and leaves. Subcanopy lighting (or under-canopy lighting) involves placing lights below the canopy, either on the benches, pots, or floor, so that light shines upward onto the lower parts of the plant. Both methods aim to improve light penetration and ensure that lower bud sites receive enough photons to contribute meaningfully to yield and quality. However, the question remains whether these methods are always the game-changer that some claim them to be.
Does more light always mean more yield?
A common misconception is that adding intercanopy or subcanopy lighting will automatically increase cannabis yields by significant margins—sometimes as high as 20% or more. While it is true that additional light can increase yield, the context is important. Many studies that report substantial yield increases with intercanopy lighting are often comparing a grow using standard top lighting with one where additional lights were incorporated within the canopy. Naturally, if more total light is added to a crop, the yield is likely to increase. However, the reality is that if a well-optimized lighting setup is already in place with sufficient photons reaching the plant, simply redistributing light within the canopy may not deliver the dramatic gains some expect. The key is not just adding light but strategically distributing the existing light to ensure it is being used efficiently.
How canopy structure determines the best lighting approach
A major factor in deciding between intercanopy and subcanopy lighting is plant morphology. In high-density setups where plants are tightly packed together, intercanopy lights might not penetrate effectively due to being surrounded by dense foliage. In contrast, subcanopy lighting may be more beneficial in this scenario, as it can illuminate the entire underside of the canopy, helping lower leaves contribute to photosynthesis. Conversely, if the plants are more widely spaced with significant gaps in the canopy, intercanopy lighting might be a more efficient way to distribute photons directly to bud sites. Every grow operation is unique, and the best approach depends on how the plants are arranged and how light naturally interacts with them.
Why subcanopy lighting is recommended in North America
Based on research conducted at Fluence, most North American growers using standard setups—such as four-foot-wide tables with rows of plants—tend to benefit more from subcanopy lighting than from intercanopy lighting. In controlled studies, it was found that using subcanopy lighting led to an average yield increase of 7.1% across multiple cannabis cultivars compared to intercanopy lighting. While this increase is not the massive 20% that some marketing claims promise, it still represents a significant and consistent boost in efficiency and profitability.
The practical challenges of intercanopy and subcanopy lighting
One often-overlooked factor is the practical execution of these lighting strategies. Intercanopy lights, for example, require physical placement among the branches, which can complicate plant maintenance, movement, and even harvesting. Growers who frequently adjust plant positioning may find intercanopy lights to be a logistical challenge. Subcanopy lighting, while easier to install and maintain, still comes with its own set of challenges, such as managing cabling properly, keeping fixtures clean, and ensuring that placement does not interfere with irrigation or airflow. Regardless of the approach chosen, integrating secondary lighting requires thoughtful planning and consideration of daily cultivation practices.
Avoiding light-induced stress
Another critical factor when deploying intercanopy or subcanopy lighting is spectrum selection. Cannabis is highly responsive to different wavelengths of light, and excessive red-light exposure can cause photo-bleaching in certain cultivars. At Fluence, research suggests that a balanced, broad-spectrum light source is the safest and most effective choice for intercanopy lighting. The VYNE 2.0 product for intercanopy lighting is BP6, which offers efficient lighting while minimizing the risk of bleaching and providing the right balance of photons to drive photosynthesis effectively.
The case for subcanopy and intercanopy lighting
From an ROI perspective, growers should consider more than just potential yield increases. The real financial benefit of intercanopy or subcanopy lighting often comes from improved bud uniformity. When lower bud sites receive sufficient light, there are fewer C-grade buds and more A and B-grade products, directly impacting profitability. However, the economics of lighting depend on the market. In some regions, high-quality buds fetch significantly more revenue, making secondary lighting a clear investment. In others, where price differences between bud grades are minimal, the ROI may not be as compelling. This is why it is always encouraged for growers to run the numbers. The team at Fluence is available to help assess whether intercanopy or subcanopy lighting makes financial sense for a specific operation.
HVAC and beyond
When light intensity is increased—whether from top lights, intercanopy, or subcanopy sources—transpiration also increases. This means that HVAC and dehumidification systems must be equipped to handle higher moisture loads. Failing to account for this can result in higher humidity, increased disease pressure, and ultimately lower yields. This is why lighting is always approached as part of a holistic environmental strategy, ensuring that all factors—light, temperature, humidity, and airflow—are working in balance.
The future of intercanopy and subcanopy lighting
Looking ahead, it is anticipated that research will continue to refine best practices for secondary lighting in cannabis cultivation. Specifically, more precise guidelines are expected to be developed to help growers determine when intercanopy or subcanopy lighting is appropriate based on canopy density and plant architecture. Additionally, spectrum optimization is likely to play a significant role in the future. There is already exploration underway to fine-tune subcanopy spectra to further enhance yield and bud quality. If successful, these advancements could fundamentally change how secondary lighting is deployed and dramatically improve efficiency for cannabis growers worldwide.
For more information:
Fluence
https://fluence-led.com/