073: Soil Nutrient Interactions and the Role of Potassium in Eastern Vineyards with Dr. Jaclyn Fiola

In this bonus episode, Fritz explains why he founded the Virtual Viticulture Academy in 2018. He describes three motivations: consulting travel limited how many growers he could serve; some growers couldn't afford or find individual advice; and vineyard management could feel isolating without nearby peers. The academy was created as a trusted source for research-based vineyard information and a community where growers can ask questions, share vineyard photos and challenges, and learn from one another. Fritz discusses how the academy now connects growers across the United States and around the world. Listen in to learn about the free grower guides, and listeners can take advantage of a membership discount: $75 off the first year with code Underground. In this episode, you will hear: Founding the Virtual Viticulture Academy in 2018

Fritz welcomes Penn State entomologist Dr. Julie Urban for a look back at ten years of spotted lanternfly research — and what vineyard owners have learned along the way. Julie explains why grapevines are especially vulnerable: late-season feeding can disrupt resource flow and drain the carbohydrate reserves vines need for winter. They walk through the lanternfly's life cycle, its unpredictable movement among host plants, and why spring nymph counts don't necessarily tell growers where adults will show up later. They also talk scouting, insecticide timing, tree of heaven, and research into gentler controls, parasitoid wasps, and even vibrations sent through trellis wires. There's no single fix yet, but Julie shares why she's hopeful — and why growers' help matters. In this episode, you will hear: A decade of spotted lanternfly research in the United States

Leading microbial ecologist from UC San Diego, Dr. Jack Gilbert joins us to talk about how soil and management decisions shape the vine and wine microbiome. We start by defining what a microbiome is in plain vineyard terms, and Dr. Gilbert explains how vines "select" specific microbes from the surrounding soil to support nutrient uptake, stress tolerance, and overall vine health. We then walk through Dr. Gilbert's Merlot study that showed roughly 95% of the vine microbiome originates from the soil, and we discuss how these early microbial reactions can influence wine character before commercial yeast ever goes in. The conversation then turns to real-world vineyard practices. We cover how herbicides, tillage, compaction, and inputs can suppress or reshape soil biology. Listeners also hear about emerging work at the UCSD Soil Health Center, including using soil "prebiotics" and "probiotics" together and developing digital twins of vineyards to time interventions more precisely. In this episode, you will hear: Vines actively recruit microbes from the soil to support health, nutrient uptake, and stress tolerance

A big life change is brewing as Fritz shares a personal update from his new home base in Denver, Colorado! After nearly two decades in Houston, he and his family have moved to be closer to the mountains, cooler weather, and an outdoor lifestyle, while still staying near a major airport so he can keep serving growers across the Americas. Nothing about the support, education, or consulting listeners receive is changing; if anything, Fritz feels more energized and inspired to bring fresh ideas to the podcast and the Virtual Viticulture Academy community. In this episode, you will hear: Reasons for relocating to Colorado and the outdoor-focused lifestyle

Fritz welcomes back Dr. Kendra Baumgartner, a longtime friend and one of his very first podcast guests, to tackle a question every grower eventually faces: when does an aging vineyard block cross from struggling to done? Kendra walks through the trunk diseases, root pathogens, and viruses that build up in vines over decades, explaining which problems a vine can carry for years and which ones signal it's time to act. Fritz and Kendra cover how to sample and diagnose these issues in the field, when retraining a vine still makes sense, and when replanting is the smarter call. Kendra brings decades of USDA plant pathology experience and now runs her own vineyard consulting practice, giving growers a clear framework for reading the signs before decline spreads across a whole block. Growers walking their older vineyards this fall will find plenty to take back into the rows. In this episode, you will hear: Trunk diseases like esca, Eutypa, and Botryosphaeria dieback, and how fast each one actually kills a vine