Navigating the Lighting Landscape: Building Uniformity and Precision in Cannabis Cultivation

An interview with Deron Caplan, PhD

Deron Caplan, PhD, is a cannabis cultivation scientist and Senior Consultant at Sostanza. With experience designing high-performance production systems across the USA, Canada, Europe, Australia, and Latin America, he specializes in integrating lighting, environmental control, and crop physiology into repeatable, data-driven cultivation strategies.

Deron shares his perspective on lighting design for commercial indoor cultivation. From PPFD targets and uniformity to planning top and under-canopy strategies and selecting reliable lighting partners.

Deron measuring LAI above the canopy.

What key lighting principles should every cultivator lock in before picking fixtures?

Deron: I think that before choosing fixtures or setting intensity targets, it’s critical to define your cultivation system. Are you working indoors or in a greenhouse? Are you targeting a high-density production model or something more specialized? What cultivars are you planning to grow (and how many), and what are their optimal PPFD targets?

Once you understand those fundamentals, I aim to establish a consistent canopy for measurement and control. In commercial-scale cannabis cultivation environments—let’s say anything over 5,000 square feet — I prefer to fix lighting height and manage PPFD through fixture output, not by raising and lowering lights. Adjusting height introduces unnecessary complexity, potential for mechanical failure and, inconsistency across batches.

How should growers think about PPFD when using top and under-canopy light?

Deron: A useful approach is to think in total PPFD applied in all directions to the canopy. For growers using only top lighting, a common target is around 1,200 µmol/m²/s. But if you’re integrating under-canopy lighting—say, 200–300 µmol/m²/s—you can reduce top lighting accordingly while keeping total intensity balanced.

For example, 900 µmol/m²/s from above plus 300 µmol/m²/s from below delivers similar total PPFD while improving lower canopy development.

What common layout mistakes do you still see in modern rooms?

Deron: Uniformity is one of the most overlooked yet impactful aspects of lighting design. Uneven light distribution, especially at the edges of rooms or along walkways, creates “border effects” that translate directly into variable yields, maturity rates, and visual quality within the same batch.

A uniform canopy ensures that all plants develop at the same pace and finish with similar characteristics. This matters both operationally and commercially: buyers notice inconsistency. Cannabis facilities that achieve tight lighting uniformity see not only better yields but also more repeatable, predictable product quality—batch after batch.

LEDs, HPS, and the Hybrid Approach

Deron: Most new lighting development for controlled environment cultivation is focused on LEDs, and for good reason: energy efficiency, tunable spectra, and refined optics continue to improve each year. That said, many experienced growers still incorporate HPS fixtures alongside LEDs to take advantage of their heat output.

Personally, I see strong results from both LED-only and mixed systems. As growers become more comfortable with LED environments—adjusting temperature, humidity, and under-canopy conditions accordingly—I think we will continue to see the industry move further toward LED-dominant designs.

Beyond spec sheets, how do you pick a lighting partner?

Deron: When we evaluate lighting systems for indoor cannabis facilities, the main differentiators aren’t usually the brand names or marketing claims. I find that many top-tier fixtures perform within a similar range of efficiency, and the differences are not detectable when scaled as often claimed. 

What truly separates great setups is how well the lighting system is planned, implemented, and supported.

At Sostanza, we evaluate lighting based on how they support our clients before and after installation. A key requirement is their ability to prepare custom light maps for the facility layout and mounting height. That step is critical for achieving uniform intensity across the canopy. Without it, you’re likely to end up with uneven growth patterns and batch-to-batch variability.

Other factors like warranty, ease of replacement, and responsiveness for technical support also carry a lot of weight. The best lighting partners view the relationship as ongoing - helping you refine your layout, troubleshoot, and adapt as your production evolves.

Selecting lights should be part of a broader cultivation strategy, not just a purchasing decision. When the system is designed around your facility, your workflow, and the strains you will grow, it becomes much easier to maintain consistency and understand the true impact of light on performance