David Hawley, Ph.D.

David Hawley is Research and Development Manager and Director of Horticultural Services at Fluence, where he leads the company’s global horticulture research program. He built the program from the ground up beginning in 2018, and it now produces the objective, replicable evidence behind Fluence’s product decisions and the cultivation guidance its customers rely on.

One of his first initiatives set the tone for the rest. When Hawley joined Fluence, every lighting manufacturer in the market was claiming its spectrum was the best one for every application — a claim that cannot be true of all of them at once, and probably of none. Rather than argue, he tested it. The Foursquare project put the four dominant spectrum styles of the day — broad white, warm white, pink, and purple — against the four largest horticulture segments: cannabis, vine crops, leafy greens, and berries. What began as a single comparison grew into fifteen projects spanning crop species and production environments, and it produced the evidence base for Fluence’s core spectrum lineup at the time: R4, R6, R6F, R8, and R9B.

Hawley’s work since has focused on getting more crop out of every kilowatt. He is the inventor of the Red Sandwich cultivation method, which reduces cannabis lighting operating expense by 26 percent against conventional practice, and a co-inventor of the T48 lighting method, which delivers roughly a 20 percent reduction. He also leads a team of cannabis cultivation consultants who work directly with commercial operators on dialing in their environments.

He earned his Ph.D. in Environmental Science at the University of Guelph’s Controlled Environment Systems Research Facility, and his peer-reviewed research includes foundational work on subcanopy lighting in cannabis as well as studies on intracanopy lighting, red photon fraction, and green light penetration in greenhouse crops. He speaks regularly through webinars and industry publications, and is a consistent advocate for scientific integrity in a market where claims routinely outpace evidence.

Area of Expertise

• Cannabis cultivation lighting
• Light spectrum optimization
• Lighting energy efficiency / OPEX reduction
• Under-canopy and intercanopy lighting
• Controlled-environment agriculture research

Credentials

• Ph.D., Environmental Science — University of Guelph, 2018 (Controlled Environment Systems Research Facility; advisor Dr. Mike Dixon)
• M.Sc., Environmental Science — University of Guelph, 2013
• B.Sc., Plant Biotechnology — University of Guelph, 2010

Experience

• 15+ years in controlled-environment agriculture across academia and industry; 8 years at Fluence (2018–present).

Notable Work

Projects and inventions:

• Led “Foursquare,” a spectrum research initiative testing four dominant spectrum styles across the four largest horticulture segments; grew into 15 projects and produced the evidence base for Fluence’s R4, R6, R6F, R8, and R9B spectra
• Co-Inventor, Fluence “Red Sandwich” cultivation method — 26% reduction in cannabis lighting OPEX
• Co-inventor, Fluence T48 lighting method — approximately 20% reduction in lighting OPEX

Selected peer-reviewed publications:

• Hawley, D., Graham, T., Stasiak, M., & Dixon, M. (2018). Improving cannabis bud quality and yield with subcanopy lighting. HortScience, 53(11), 1593–1599.
• Schouten, I., Hawley, D., Olschowski, S., Ouzounis, T., et al. (2024). Partially substituting top-light with intracanopy light increases yield more at higher LED light intensities. HortScience, 59(3), 421–428.
• Kusuma, P., Ouzounis, T., Hawley, D., et al. (2022). On the pros and cons of red photons for greenhouse tomato production. The Journal of Horticultural Science and Biotechnology.
• Lanoue, J., Little, C., Hawley, D., & Hao, X. (2022). Addition of green light improves fruit weight and dry matter content in sweet pepper due to greater light penetration within the canopy. Scientia Horticulturae, 304, 111350.

Recent webinars and articles:

• Red Sandwich: A New Way to Cultivate More for Less — Fluence Webinar
• Maximizing Cannabis Yield with Intercanopy Lighting — Fluence Webinar
• Fluence Research: How Light Affects Photobleaching in Cannabis
• Die Rolle von rotem Licht beim Anbau