Episode 165: Boosting Yields 50% with a 13-Hour Photoperiod? Debunking Cannabis Science with Dr. Youbin Zheng

Cannabis Cultivation and Science Podcast

Tad Hussey.

Grow, Leisure, Natural Sciences, Cannabis, Science, Cultivation, Gardening, Weed, Organics, Home & Garden, Growing, Marijuana

4.7 • 716 Ratings

🗓️ 19 May 2026

⏱️ 67 minutes

🔗️ Recording | iTunes | RSS

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Summary

Can a simple 1-hour change to your lighting schedule increase your flower yields by 50% and your THC by 9%? On this week’s episode of the Cannabis Cultivation and Science Podcast, host Tad Hussey sits down with leading horticulture professor Dr. Youbin Zheng from the University of Guelph in Ontario, Canada. Dr. Zheng is a principal investigator at the absolute forefront of high-THC cannabis agronomy and the author of the definitive textbook, Handbook of Cannabis Production in Controlled Environments. Drawing directly from peer-reviewed data conducted inside commercial licensed facilities, Tad and Dr. Zheng smash some of the industry’s most deeply rooted legacy myths. They dive into why heavy phosphorus feeding is reducing your profits, the surprising truth about how modern high-THC genetics react to supplemental UV light, and the exact science behind using controlled deficit irrigation to trigger a late-flower cannabinoid spike. Whether you are managing a large-scale commercial facility or navigating a boutique organic living soil bed, Dr. Zheng’s pragmatic, data-first approach offers actionable insights to dramatically optimize your canopy’s ROI.

Transcript

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0:00.0	Welcome to the Cannabis
0:03.0	and Science Podcast. I'm your host, Tad Hussey of Kiss Organics.
0:23.0	This is the podcast where we discuss the cutting edge of growing from a science-based perspective
0:27.2	and drawn top experts from around the industry to share their wisdom and knowledge.
0:31.9	My guest this week is Dr. Yubin Zhang.
0:34.5	Dr. Zhang is a professor at the University of Guelph in Ontario, Canada, where his lab
0:39.3	has been at the forefront of high-THC cannabis research since the country legalized recreational use
0:44.8	in 2018. As a principal investigator, he collaborates directly with licensed commercial facilities
0:50.8	to ensure his lab's research can be applied by growers right away. He is also the author of the recently published Handbook of Cannabis Production and Controlled
0:59.0	Environments, a definitive scientific resource for students and cultivators alike.
1:04.0	Dr. Zhang and his team of talented graduate students and research associates look closely at all aspects of indoor and greenhouse horticulture
1:11.7	management ranging from light intensity and spectrum to deficit irrigation and proper crop nutrition.
1:17.8	His breakthrough findings on extended photo periods, UV radiation, and phosphorus thresholds
1:22.7	are actively changing the way cultivators optimize their facilities and manage plant health.
1:27.3	Joining us today to talk about how a 13-hour day cycle can radically increase flour yield,
1:32.5	the realities of utilizing drought stress and late flour, and why the industry is vastly
1:36.8	over-applying phosphorus is Dr. Eubin Zhang.
1:39.3	Now on to the show.
1:44.0	Dr. Zhang, thank you so much for coming on the podcast today. Thank you for having me.
1:50.9	Yeah, I was fortunate enough to hear you speak at PhotoX. I think I've actually heard you speak there a couple
1:56.7	times now. And you shared some of your research around photobiology and I'd love to talk
2:03.5	to you about that but can you share a little bit about yourself in your lab? Sure, yeah, it's always
	...

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