In this episode of Vineyard Underground, Fritz talks with Dr. Mark Krasnow of Thoughtful Viticulture about how to tell real vine stress from false alarms in the vineyard.
Mark explains why grapevines are often tougher than they look and breaks stress into three main categories: water, heat, and wind. He and Fritz highlight common misreads and show how these assumptions lead to overwatering, shallow roots, excess vigor, and higher disease risk.
The conversation focuses on using data instead of guesswork, pairing tools such as pressure bombs, porometers, and soil moisture probes so growers can set meaningful irrigation thresholds. Mark also shares why he prefers early-season water stress for red varieties to influence berry size and phenolics, while keeping vines better supplied after veraison.
They compare stress responses in young versus mature vines and touch on Mark’s work with powdery mildew spore monitoring, which suggests many early-season sprays may be unnecessary.
In this episode, you will hear:
- Why grapevines are often more resilient than growers assume
- How overwatering can create shallow roots, excess vigor, and more disease risk
- The difference between perceived water stress and measured stress
- How to pair soil moisture probes with pressure bomb readings to set a real “red line” for irrigation
- Why early-season water stress can improve red wine quality when managed correctly
- How vine age affects stress tolerance and root development
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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.
Have a vineyard question? Go to VineyardUndergroundPodcast.com and click the Ask Fritz button.
Today’s Guest:
Dr. Mark Krasnow is a renowned plant physiologist and consultant and the founder of Thoughtful Viticulture – a company that helps vineyards grow the highest quality fruit in the most sustainable and efficient manner possible.
Connect with Mark at thoughtfulviticulture.com and follow him @drkraz or on his blog https://www.thoughtfulviticulture.com/blog.
Episode Sponsor:
Today’s episode was brought to you by HydroGeo Environmental and SensorInsight.
Thank you to HydroGeo Environmental for sponsoring today’s episode. For over 20 years, Bubba Beasley and his team have helped vineyard growers with site assessments, mapping, soil and groundwater evaluations, and optimal vineyard layouts. Using the latest technology and industry expertise, HydroGeo brings clarity to even the most complex landscapes. Visit HydroGeoEnvironmental.com and mention the Vineyard Underground podcast for a special discount on your service.
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.
