075: The Importance of Mycorrhizal Fungi for Vineyard Health with Dr. R. Paul Schreiner
Release Date: 07/08/2025
080: Transitioning from Grape Grower to Winemaker with Jim Duane - Part 1
Vineyard Underground
Many vineyard owners eventually consider moving beyond grape growing into winemaking, whether to create a new revenue stream, take control of their fruit, or explore a more creative outlet. In this episode, we welcome winemaker and podcaster Jim Duane of Seavey Vineyard and the Inside Winemaking podcast for the first part of a two-part discussion on how growers can make this transition successfully. The conversation discusses the mindset, skills, and resources needed to move from vineyard to cellar. Jim shares why a formal chemistry degree isn’t required to produce quality wine, how growers...
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079: Plan My Vineyard with Matthieu Wheeler
Vineyard Underground
In this episode, Fritz walks through the full planning process for a brand-new vineyard alongside guest Matthieu Wheeler. Matthieu, the winemaker at Cassidy Hill Vineyard in Connecticut and founder of Wheeler Winery, is preparing to establish his own vineyard on a newly purchased property. With Fritz’s guidance, listeners get a behind-the-scenes look at what goes into selecting vineyard sites, designing blocks, and preparing the land for long-term success. Fritz and Matthieu cover vineyard economics, including the realistic costs of establishing and maintaining vines, equipment investments,...
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078: Beyond Organic Wine with Adam Huss
Vineyard Underground
In this episode of Vineyard Underground, Fritz welcomes Adam Huss — host of the Beyond Organic Wine podcast, winemaker at Centralas Wine, and creator of the Crenshaw Cru Wine Garden in South Los Angeles. Adam shares his unconventional path into winemaking, beginning with a career in the nonprofit sector before launching a winery focused on ecological and community-driven practices. The conversation explores Adam’s philosophy of going “beyond organic” to embrace an ecological approach to winegrowing — one that avoids getting boxed into industry buzzwords and instead focuses on the...
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077: Transitioning Vineyards to Regenerative Organic Certification with Hilary Graves
Vineyard Underground
In this episode, we welcome Hilary Graves, Vineyard and Grower Relations Manager at Booker Wines, to discuss how she successfully transitioned an Organic vineyard to regenerative organic certification. With over 20 years of field experience on California’s Central Coast, Hilary brings practical strategies and candid stories about what it really takes to move beyond standard organic practices. Hilary explains the core pillars of regenerative organic certification — soil health, social fairness, and animal welfare — and why she and the team at Booker Wines chose to pursue this path. She...
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076: Growing Grapes Around the World – England with Dr. Belinda Kemp
Vineyard Underground
In this episode of Vineyard Underground, we welcome Dr. Belinda Kemp, viticulture and enology researcher at NIAB in East Malling, England, to explore the evolving wine industry in the UK. With a background in theatrical arts and a PhD in Pinot Noir, Dr. Kemp brings a dynamic perspective to the scientific and practical aspects of cool climate viticulture. The conversation covers England’s emerging reputation for sparkling wine, the impact of climate variability on grape production, and the country's increasing focus on sustainability and innovation. Dr. Kemp discusses the shift from...
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075: The Importance of Mycorrhizal Fungi for Vineyard Health with Dr. R. Paul Schreiner
Vineyard Underground
In this episode of Vineyard Underground, Fritz welcomes Dr. R. Paul Schreiner, recently retired research plant physiologist from the USDA, for a deep dive into the fascinating world of mycorrhizal fungi and their impact on vineyard health. With over two decades of research experience in grapevine physiology and root biology, Dr. Schreiner shares the critical roles these fungi play in nutrient uptake, root efficiency, drought tolerance, and overall soil structure. Fritz and Dr. Schreiner explore what arbuscular mycorrhizal fungi (AMF) are, how they form symbiotic relationships with grapevine...
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074: Variation in Young Vine Training in Diverse Climates
Vineyard Underground
In this solo episode, we take a deep dive into the many variables that influence young vine training in different climates. Listeners will gain a clear understanding of how climate, trellis selection, rootstock vigor, and regional weather risks shape vine training strategies. Fritz explains how cold-climate growers often rely on double trunks or “spare parts viticulture” to prepare for winter damage, while warmer-climate vineyards may benefit from fast-tracking techniques like green topping and one-shoot training for quicker vineyard establishment. We walk through scenarios where...
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073: Soil Nutrient Interactions and the Role of Potassium in Eastern Vineyards with Dr. Jaclyn Fiola
Vineyard Underground
In this episode of Vineyard Underground, Fritz welcomes soil scientist Dr. Jaclyn Fiola for an in-depth discussion on one of viticulture’s most misunderstood nutrients — potassium. Drawing from her recent research and extensive fieldwork across the Mid-Atlantic region, Jaclyn breaks down how potassium behaves differently from other macronutrients, where it originates in the soil, and what makes its availability so complex for grape growers. Fritz and Jaclyn explore why vineyards in the Eastern U.S. often see discrepancies between soil and tissue potassium levels and how that can impact...
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072: How Research Influences Our Spray Program Decisions with Dr. Katie Gold
Vineyard Underground
In this episode of Vineyard Underground, host Fritz Westover welcomes Dr. Katie Gold, Assistant Professor of Grape Pathology at Cornell University, for a deep dive into how research drives informed spray program decisions in the vineyard. Dr. Gold brings her extensive expertise in grape disease management to the conversation, shedding light on how growers can use scientific data and field research to refine their fungicide strategies and protect their crops more effectively. Fritz and Katie explore the critical role of disease forecasting models, including how they are developed and validated,...
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071: Demystifying Spray Adjuvants with Paul Crout
Vineyard Underground
In this episode, we are joined by a friend and repeat guest, Paul Crout. Paul is a leading pest control advisor, certified crop control advisor, and one of the foremost experts on wine grape nutrition, spray adjuvants, and more in the ag and viticulture realm. He currently works as a leading agronomist with Helena Agra Enterprises in California, and he has the honor of being the only guest we've had on the podcast three times! Adjuvants can be a dry topic, but we promise this discussion provides a lot of valuable take-home information. It’s one of those episodes where you will want to take...
info_outlineIn this episode of Vineyard Underground, Fritz welcomes Dr. R. Paul Schreiner, recently retired research plant physiologist from the USDA, for a deep dive into the fascinating world of mycorrhizal fungi and their impact on vineyard health. With over two decades of research experience in grapevine physiology and root biology, Dr. Schreiner shares the critical roles these fungi play in nutrient uptake, root efficiency, drought tolerance, and overall soil structure.
Fritz and Dr. Schreiner explore what arbuscular mycorrhizal fungi (AMF) are, how they form symbiotic relationships with grapevine roots, and why grapes are considered “super hosts.” They discuss how AMF enhances phosphorus acquisition, especially in low-P soils, and how they support the uptake of other nutrients like potassium, zinc, and copper. They also talk about factors that suppress or encourage fungal colonization, such as excessive fertilization, cultivation, cover cropping, and herbicide use.
Dr. Schreiner also previews ongoing research from the High-Resolution Vineyard Nutrition Project, which is helping redefine best practices for tissue sampling and nutrient timing. Whether you’re planting a new vineyard or managing an established one, this episode offers an essential look at how understanding underground biology can elevate your vineyard management decisions.
In this episode, you will hear:
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How grapevines form symbiotic relationships with mycorrhizal fungi
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Why phosphorus is the most important nutrient supported by AMF
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The effects of nitrogen and phosphorus fertilization on fungal colonization
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Whether commercial AMF inoculants are worth the investment
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Practices that promote healthy fungal populations in vineyard soil
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Resources:
If you are starting a vineyard or thinking about starting a vineyard, apply to be on the podcast for Fritz’s help planning your vineyard – VineyardUndergroundPodcast.com/Contact/
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Today’s Guest:
Dr. R. Paul Schreiner is a research plant physiologist specializing in research on grapevine physiology with a focus on plant nutrition and the functioning of roots and arbuscular mycorrhizal fungi. He is currently working with the High Resolution Vineyard Nutrient Management Project as a co-director, leading the plant nutrition and product quality group.
Connect with Paul through the High Resolution Vineyard Nutrient Management Project: https://highresvineyardnutrition.com/.
Episode Sponsor:
Today’s episode was brought to you by the Inside Winemaking podcast.
Thank you to the Inside Winemaking podcast for sponsoring today’s episode. To learn more about the art & science of winemaking with Jim Duane, visit www.insidewinemaking.com/ and listen to the Inside Winemaking podcast on your favorite podcast app with new episodes releasing every other Tuesday.
Episode Credits
If you like this podcast and are thinking of creating your own, consider talking to my producer, Emerald City Productions. They helped me grow and produce the podcast you are listening to right now. Find out more at https://emeraldcitypro.com. Let them know we sent you.