Vineyard Underground

Small vineyard decisions made early in the season can create major ripple effects later in the year, and in this episode, Fritz breaks down three vineyard management tasks that are frequently skipped, delayed, or underestimated despite their outsized impact on vine health, fruit quality, and long-term vineyard performance.
Fritz focuses first on shoot thinning and explains why timing is everything. He walks through the economic and practical advantages of thinning early, including improved spray penetration, better airflow, easier hand harvesting, and even reduced pruning labor during dormancy. 
He then explains why bloom and veraison sampling windows are critical for understanding nutrient status and preventing deficiencies before they become costly problems. Lastly, he tackles water stress monitoring and the common misconceptions surrounding vineyard stress. 
Listen in for practical ways growers can monitor irrigation effectiveness, evaluate soil moisture, and avoid relying solely on visual assumptions about vine stress levels. Remember, better data leads to better vineyard decisions.
In this episode, you will hear:
Early shoot thinning can improve fruit quality, airflow, spray coverage, and long-term pruning efficiency

Delayed shoot thinning increases labor costs and creates more winter pruning wounds susceptible to trunk disease

Tissue sampling at bloom and veraison helps growers identify nutrient deficiencies before productivity suffers

Leaf blade sampling may provide more reliable nutrient data than petiole sampling for many nutrients

Water stress should be monitored with both field observation and measurable soil moisture data

Excess vigor, nutrient imbalance, weather extremes, fungal disease, and insects can all contribute to flower browning during bloom

Follow and Review:
If you enjoyed this episode, be sure to follow the podcast and leave a 5-star review on Apple Podcasts! Your support helps us reach more listeners. 💜 Click the '+' in the top right corner of Apple Podcasts to follow now.
Resources:
Get Fritz's Shoot Thinning, Tissue Sampling, and Plant Stress resources available for podcast listeners at VirtualViticulureAcademy.com/tasks.
Have a vineyard question? Go to VineyardUndergroundPodcast.com and click the Ask Fritz button.
Episode Sponsor:
Today's episode was brought to you by SensorInsight and Clemens Technologies.
Thank you to SensorInsight for sponsoring today's episode. SensorInsight is a leader in vineyard soil moisture and weather monitoring. SensorInsight designs state-of-the-art, remote satellite monitoring of soil moisture and weather, bringing actionable information for your vineyard operations straight to your phone, with real-time data so you can best decide when to turn on your irrigation, how long to run the system, and learn how the dynamics of soil moisture can change over a given season. Visit them today at https://sensorinsight.io. And don't forget to mention the code Underground to receive a discount on your SensorInsight solution.
Thank you to Clemens Technologies for sponsoring today's episode. Clemens Technologies is the market leader in machinery for all elements of vineyard management. Visit https://www.clemens-online.com/us/ and provide the code UNDERGROUND to receive 5% off your order of in-stock machinery. Or reach out to Thomas Clemens directly at [email protected] with any questions.
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.

We are back with another solo episode! Fritz dives into the world of Reddit viticulture advice to separate helpful guidance from misleading recommendations. Using real vineyard and winemaking questions pulled from Reddit threads, Fritz evaluates the quality of the responses while adding his own professional perspective.
The episode covers a wide range of vineyard topics, but throughout it, Fritz highlights an important lesson for growers at every level: context matters. Many online answers contain kernels of truth, but successful vineyard management depends on site conditions, climate, soil, vine age, regional disease pressure, and long-term goals. He explains why broad internet advice often lacks the specificity growers actually need to make confident decisions.
Listeners will come away with a fresh perspective on vineyard establishment, irrigation management, pruning strategies, disease prevention, and realistic expectations for small-scale winegrowing projects.
In this episode, you will hear:
Establishing vineyards in cool climates like the UK and Northern Europe

PIWI grape varieties and disease-resistant planting strategies

Realistic timelines for vineyard establishment and first harvests

Challenges of starting and managing a small hobby vineyard

Irrigation management for young vines during extreme summer heat

Reviving neglected Frontenac and Edelweiss vineyards in the Midwest

Follow and Review:
If you enjoyed this episode, be sure to follow the podcast and leave a 5-star review on Apple Podcasts! Your support helps us reach more listeners. 💜 Click the '+' in the top right corner of Apple Podcasts to follow now.
Resources:
If you're starting a vineyard or thinking about starting a vineyard, visit https://www.virtualviticultureacademy.com/growsmart to get Fritz's online Prospective Winegrape Grower Course to help you get your vineyard planned and planted correctly from the start. Use the code PODCAST at checkout to save $89.99 as a thank you for being a podcast listener.
Get more information from Fritz about soil moisture sensors – types of sensors, location and placement, installation, and understanding soil monitoring data at https://www.virtualviticultureacademy.com/sensor.
Have a vineyard question? Go to VineyardUndergroundPodcast.com and click the Ask Fritz button.
Episode Sponsor:
Today's episode was brought to you by Vintner's Vault and Vigneron Toy Store.
Thank you to Vintner's Vault for sponsoring today's episode! Vintner's Vault is the #1 winery equipment company that I recommend to my growers, who are also winemakers. Visit TheVintnerVault.com and use the code UNDERGROUND5 (all caps) to save 5% off of your online order, or mention that you heard about them on the Vineyard Underground podcast when contacting them for a larger piece of equipment, consulting services, or turn-key packages, and they will provide a podcast listener discount for you. 
Thank you to Vigneron Toy Store for sponsoring today's episode. Vigneron Toy Store specializes in Harvesters, Sprayers, Frost Mitigation Equipment, Canopy Management Trimmers, and more. As grape growers themselves, they can expertly help you determine the best equipment for your specific vineyard needs. And, as a special offer for our podcast listeners, you can save 5% off in-stock machines by entering the promo code Underground on the contact form at vignerontoystore.com.
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.

Plant growth regulators (PGRs) are powerful tools that can dramatically influence vine performance, but they also come with complexity and risk. In this episode, Fritz welcomes back Dr. Matthew W. Fidelibus of UC Davis to explore how these compounds are used across table, raisin, and wine grape production.
Dr. Fidelibus explains that PGRs include both naturally occurring plant hormones and synthetic compounds that mimic hormonal effects. While they've long been foundational in table grape production, their use in winegrapes is far less common and more nuanced. The conversation highlights how sensitivity to timing, rate, and variety is critical, with even small misapplications potentially affecting fruit set, bud development, or yields across multiple seasons.
Fritz and Dr. Fidelibus dig into specific compounds like gibberellic acid, abscisic acid, and ethephon, discussing how they can influence berry size, cluster architecture, color development, and ripening. They also explore emerging research on improving color in virus-affected vineyards, delaying ripening in warm climates, and even modifying aroma profiles.
A key takeaway is that PGRs are not a one-size-fits-all solution. They require careful evaluation, regulatory compliance, and, ideally, small-scale trials before broader use. For growers facing challenges like poor fruit set, uneven ripening, or compact clusters, these tools may offer targeted solutions — but only when used with precision and a strong understanding of vine physiology.
Listeners will walk away with a clearer understanding of both the potential and the pitfalls of incorporating PGRs into vineyard management.
In this episode, you will hear:
Overview of plant growth regulators and how they influence vine physiology

Historical use of PGRs in table and raisin grape production

Key compounds like gibberellic acid, abscisic acid, and ethephon

Applications for cluster thinning, berry sizing, and color development

Challenges and risks of using PGRs in winegrapes

Emerging research, including virus mitigation and ripening control

Follow and Review:
If you enjoyed this episode, be sure to follow the podcast and leave a 5-star review on Apple Podcasts! Your support helps us reach more listeners. 💜 Click the '+' in the top right corner of Apple Podcasts to follow now.
Resources:
Come grow with Fritz through https://www.virtualviticultureacademy.com! Save $75 off your first year of membership with the code Underground at checkout.
Have a vineyard question? Go to VineyardUndergroundPodcast.com and click the Ask Fritz button.
Today's Guest:
Dr. Matthew W. Fidelibus is an extension specialist in the Department of Viticulture and Enology, UC Davis. 
Connect with Matthew and view his research – https://wineserver.ucdavis.edu/people/matthew-fidelibus#/ or follow him at https://bsky.app/profile/viticulture.bsky.social 
Episode Sponsor:
Today's episode was brought to you by Clemens Technologies and SensorInsight.
Thank you to Clemens Technologies for sponsoring today's episode. Clemens Technologies is the market leader in machinery for all elements of vineyard management. Visit https://www.clemens-online.com/us/ and provide the code UNDERGROUND to receive 5% off your order of in-stock machinery. Or reach out to Thomas Clemens directly at [email protected] with any questions.
Thank you to SensorInsight for sponsoring today's episode. SensorInsight is a leader in vineyard soil moisture and weather monitoring. SensorInsight designs state-of-the-art, remote satellite monitoring of soil moisture and weather, bringing actionable information for your vineyard operations straight to your phone, with real-time data so you can best decide when to turn on your irrigation, how long to run the system, and learn how the dynamics of soil moisture can change over a given season. Visit them today at https://sensorinsight.io. And don't forget to mention the code Underground to receive a discount on your SensorInsight solution.
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.

Organic grape production is gaining momentum, but making the transition from conventional farming requires careful planning, patience, and a willingness to adapt. In this episode of Vineyard Underground, Fritz welcomes Rob Warren, owner and operator of Desert Willow Vineyard and Warren Farms in Seminole, Texas, to share his experience converting his vineyard to certified organic production.
Rob explains how his agricultural background in organic row crops gave him experience with organic systems long before he applied those principles to grape growing. As consumer demand began to shift toward more natural and sustainably produced wines, wineries started seeking organic fruit, prompting Rob to pursue certification.
During the conversation, Fritz and Rob walk through the realities of transitioning a vineyard to organic management. Rob discusses the three-year certification timeline, the importance of documenting the final use of conventional inputs, and the need for growers to rethink pest, disease, and weed management strategies.
A major focus of the episode is that Rob uses sheep in the vineyard. The sheep help control weeds, provide natural fertilization, and even assist with canopy management by removing leaves in the fruiting zone.
Throughout the episode, Rob provides honest background information on the challenges and the long-term benefits of improved soil health and stronger vine resilience.
For vineyard owners considering organic production, this episode offers practical guidance and real-world lessons from a grower who has successfully made the switch.
In this episode, you will hear:
Market demand from wineries and consumers increasingly favors organic grape production

Weed management is often the biggest early challenge when moving away from conventional herbicides

Sheep can play a valuable role in weed control, fertilization, and canopy leaf removal

Organic pest and disease control often requires more frequent monitoring and spray applications

Soil health improvements through cover crops and livestock integration strengthen long-term vineyard resilience

Follow and Review:
If you enjoyed this episode, be sure to follow the podcast and leave a 5-star review on Apple Podcasts! Your support helps us reach more listeners. 💜 Click the '+' in the top right corner of Apple Podcasts to follow now.
Resources:
Register for Fritz's live, virtual two‑day Early Season Vineyard Management Bootcamp on April 22nd and 23rd.
Come grow with Fritz through https://www.virtualviticultureacademy.com! Save $75 off your first year of membership with the code Underground at checkout. 
Have a vineyard question?  Go to VineyardUndergroundPodcast.com and click the Ask Fritz button.
Today's Guest:
Rob Warren is the owner and operator of Desert Willow Vineyard and Warren Farms in Seminole, Texas, and a leading innovator in regenerative and organic vineyard management and farming. 
Connect with Rob:
Facebook: https://www.facebook.com/desertwillowvineyard 

Instagram: https://www.instagram.com/desertwillowvineyard/ 

YouTube: https://www.youtube.com/channel/UCrjWaulJw7tATQC3trzhPJQ 

Episode Sponsor:
Today's episode was brought to you by Clemens Technologies and Sunridge Nurseries.
Thank you to Clemens Technologies for sponsoring today's episode. Clemens Technologies is the market leader in machinery for all elements of vineyard management. Visit https://www.clemens-online.com/us/ and provide the code UNDERGROUND to receive 5% off your order of in-stock machinery. Or reach out to Thomas Clemens directly at [email protected] with any questions.
Thank you to Sunridge Nurseries for sponsoring today's episode. Sunridge Nurseries is the exclusive nursery sponsor of the Vineyard Underground podcast. They have been a family-owned company for over 45 years, and their dedicated focus on quality and consistency has grown them into the largest supplier of grapevines in both North and South America and the industry leader in nursery standards. Visit them today at SunridgeNurseries.com and mention the code Underground to receive a podcast listener discount on your vine order.
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.

In this final installment of the Vineyard Nutrition Essentials series, Fritz is joined by Dr. Jaclyn Fiola, Assistant Professor of Soil and Environmental Science at Delaware Valley University, to unpack the critical role magnesium plays in vineyard health and productivity. Building on prior discussions around potassium, the conversation explores how magnesium functions as a key macronutrient, particularly as the central component of chlorophyll and a driver of photosynthesis and energy transfer in grapevines.
Dr. Fiola explains that magnesium primarily originates from soil minerals, especially in darker, magnesium-rich parent materials, and that soil characteristics such as pH, texture, moisture, and cation exchange capacity influence its availability. There is a delicate balance between magnesium, potassium, and calcium, and nutrient competition can lead to deficiencies even when soil levels appear adequate.
Listeners will learn how to identify magnesium deficiency symptoms, including interveinal chlorosis in older leaves, and why these symptoms typically emerge later in the growing season. The episode also underscores the importance of accurate diagnosis through soil and tissue testing to avoid mismanagement.
Listen now to learn the important role of magnesium in your vineyard.
In this episode, you will hear:
Magnesium as a core component of chlorophyll and photosynthesis

Soil pH, texture, and moisture driving nutrient availability

Competition between magnesium, potassium, and calcium

Late-season deficiency symptoms and how to recognize them

Importance of tissue testing for accurate diagnosis

Pre-plant and in-season magnesium correction strategies

Follow and Review:
If you enjoyed this episode, be sure to follow the podcast and leave a 5-star review on Apple Podcasts! Your support helps us reach more listeners. 💜 Click the '+' in the top right corner of Apple Podcasts to follow now.
Resources:
Visit www.virtualviticultureacademy.com/sampling to access Fritz's how-to guides and videos for proper sampling and target nutrient values.
Listen to Dr. Jaclyn Fiola's previous podcast episode (episode 73) to learn about the role of potassium in vineyards.
Have a vineyard question? Go to VineyardUndergroundPodcast.com and click the Ask Fritz button.
Come grow with Fritz through https://www.virtualviticultureacademy.com! Save $75 off your first year of membership with the code Underground at checkout. 
Today's Guest:
Dr. Jaclyn Fiola is a soil scientist who specializes in vineyard soils and soil science pedagogy. She works as an Assistant Professor of Soil and Environmental Science at Delaware Valley University.
Connect with Jaclyn, follow her, and view her research.
Episode Sponsor:
Today's episode was brought to you by Vigneron Toy Store and Shellt Grow Tubes.
Thank you to Vigneron Toy Store for sponsoring today's episode. Vigneron Toy Store specializes in Harvesters, Sprayers, Frost Mitigation Equipment, Canopy Management Trimmers, and more. As grape growers themselves, they can expertly help you determine the best equipment for your specific vineyard needs. And, as a special offer for our podcast listeners, you can save 5% off in-stock machines by entering the promo code Underground on the contact form at vignerontoystore.com.
Thank you to Shellt Grow Tubes for sponsoring today's episode. Shellt makes the ultimate grow tubes for grape vines and orchard trees. Their grow tubes are reusable, recyclable, and designed to grow with your vineyard by clicking together for taller or wider coverage. I exclusively recommend Shellt Grow Tubes to the growers I work with. Visit https://www.shellt.us/ and order with the code UNDERGROUND to save 15% off all online orders, plus free shipping within the continental United States.
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.