Episode 152: Light, Spectrum, and Plant Signals — A Practical Guide with Dr. David Hawley part 2
In this episode, I sit down with Dr. David Hawley to talk about what plants actually care about when it comes to light. We dig into how to think in DLI instead of just chasing PPFD numbers, why uniformity matters more than raw power, and how spectrum fine-tunes rather than defines your grow. David breaks down what far-red and UV really do (and don’t do), how to manage leaf temperature as light intensity climbs, and why clean lenses and smart dimming often beat a fancy new fixture. It’s a practical, myth-busting chat about using light as a tool—not a trophy—and it’s packed with tips you can apply right away whether you’re running a living soil facility or just trying to dial in a tent at home.
Cannabis Cultivation and Science Podcast · Fluence Lighting, Dr. David Hawley, KIS Organics, Tad Hussey
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Show Notes
In this conversation, Tad and Dr. David Hawley (Chief Science Officer at Fluence) unpack what really matters when dialing in your lighting strategy for cannabis and other high-value crops. They get deep into how plants perceive light, what “good spectrum” actually means, and how to think about intensity, uniformity, and plant response in a more scientific (and practical) way.
Topics covered include:
Understanding Daily Light Integral (DLI) and how it relates to plant metabolism
When to use far-red and what to expect from it
The truth about UV lighting and secondary metabolite production
Managing leaf temperature and avoiding hidden stress from high PPFD
How fixture placement and uniformity impact yield and morphology
Using dimming strategies through different growth stages
Why overemphasizing spectrum specs can distract from the real gains
Practical steps for mapping your grow and verifying performance
David also shares insights on under-canopy lighting, canopy architecture, and the future of horticultural light design, offering takeaways for both commercial cultivators and serious home growers.
Resources mentioned:
Fluence by OSRAM
KiS Organics Living Soil & Nutrients
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