Turfgrass Epistemology

In this episode of Turfgrass Epistemology, I discuss the peer-reviewed article “Dollar Spot Resistance among Blends of Creeping Bentgrass Cultivars” by Abernathy et al. (2001), published in Crop Science. This study evaluates whether blending creeping bentgrass cultivars can reduce dollar spot severity compared to monostands on golf course putting greens. I explain how highly susceptible cultivars...

In this episode of Turfgrass Epistemology, I break down the classic Crop Science paper “Assessing Irrigation Management for Its Effects on Disease and Weed Levels in Perennial Ryegrass” by Jiang, Fry, and Tisserat (1998). This study directly examines how irrigation scheduling (daily vs. ET-based irrigation) influences brown patch, dollar spot, weed pressure, pesticide use, and turf quality on pere...

In this episode of Turfgrass Epistemology – Comments & Emails Part 2, I continue responding to viewer questions and email discussions about turfgrass management, soil testing, fertilizer programs, dollar spot control, and common lawn care myths. This follow-up video addresses new comments from golf course superintendents, lawn care operators, and homeowners who are trying to separate evidence-...

In this episode of Turfgrass Epistemology, I respond to viewer comments and emails covering some of the most common questions and misconceptions I see about turfgrass science, soil fertility, nutrient management, and disease control. I address recurring themes from golf course superintendents, lawn care professionals, and homeowners, explain where confusion often arises, and clarify how peer-revie...

In this episode of Turfgrass Epistemology, I discuss the peer-reviewed article “Dollar Spot and Gray Leaf Spot Severity as Influenced by Irrigation, Chlorothalonil, Paclobutrazol, and a Wetting Agent” by McDonald, Dernoeden, and Bigelow (2006), published in Crop Science. This landmark study examines how irrigation regime, soil moisture, and common management inputs influence dollar spot and gray l...

In this episode of Turfgrass Epistemology, I discuss and interpret the peer-reviewed article “Optimizing Liquid-Applied Iron Sulfate Rate and Application Interval for Dollar Spot Suppression on Golf Course Fairways” by Soldat et al. (2024), published in Crop Science. This paper builds on earlier iron sulfate research and focuses on practical optimization—how rate, application interval, and spray v...

In this episode of Turfgrass Epistemology, I discuss and interpret the peer-reviewed article “Influence of Ferrous Sulfate and Its Elemental Components on Dollar Spot Suppression” by McCall et al. (2016), published in Crop Science. This paper is foundational to many modern discussions about using iron—specifically ferrous sulfate—as a tool for managing dollar spot on creeping bentgrass putting gre...

In this episode of Turfgrass Epistemology, I discuss and critically interpret the peer-reviewed article “Impact of Ferrous Sulfate Concentration on Clarireedia Isolate Growth and Dollar Spot Development” by Shelton et al. (2021), published in Crop Science. This paper is frequently cited in conversations about using iron—specifically ferrous sulfate—as a non-fungicidal tool for dollar spot suppress...

In this episode of Turfgrass Epistemology, I break down and discuss the peer-reviewed article “Dollar Spot Suppression on Creeping Bentgrass in Response to Repeated Foliar Nitrogen Applications” by Townsend et al. (2021), published in Plant Disease. This paper directly addresses one of the most common and controversial questions in turfgrass management: can nitrogen fertilization meaningfully supp...

In this episode of Turfgrass Epistemology, I critically examine and respond to two popular soil fertility videos that promote base saturation theory and a simplified soil pH–nutrient availability diagram, and I explain why both should be treated with extreme skepticism—or ignored entirely—when making turfgrass management decisions. Much of the base saturation messaging presented in these videos re...

In this episode of Turfgrass Epistemology, I walk through a recent peer-reviewed study that examines how potassium fertilization influences dollar spot severity on annual bluegrass (Poa annua) and creeping bentgrass (Agrostis stolonifera) putting greens. The article, Potassium fertilization effects on dollar spot of annual bluegrass and creeping bentgrass, presents multi-year field data showing th...

In this episode of Turfgrass Epistemology, I review and respond to comments, emails, and TikTok messages I’ve received throughout 2025 related to turfgrass science, soil fertility, nutrient management, and common turf industry claims. From thoughtful questions to recurring misconceptions, this video highlights what turf managers, lawn care professionals, golfers, and homeowners are asking—and wher...

In this episode of Turfgrass Epistemology, I sit down with Dr. John Inguagiato to discuss his peer-reviewed research on phosphite use for suppressing cyanobacteria (blue-green algae) on putting greens. Together, we break down the science behind phosphite chemistry, application rates, turf safety, and what the data actually say—beyond marketing claims. Dr. Inguagiato’s 2017 Crop Science paper, “Eff...

In this video I take a close, critical look at "Data-Drive Lawn Care" (https://www.youtube.com/watch?v=pjRXNcIi3Hk) and share my honest thoughts on what works — and what doesn’t. I break down the arguments, highlight where I think the logic falls short, and offer my own perspective on the topic. 🔎 What I cover: Key claims made by the original creator Moments where I agree — and moments where I re...

In this video, I review and break down one of the most referenced articles in cool-season turfgrass pathology: “Severity of Gray Leaf Spot in Perennial Ryegrass as Influenced by Mowing Height and Nitrogen Level” by Williams, Burrus, and Vincelli (2001). This study investigated how two major management practices—mowing height and nitrogen rate—affect the intensity of gray leaf spot (Pyricularia gri...

In this video, I provide an in-depth, evidence-based critique of the nitrogen-efficiency product RDX-N and the claims made in the promotional video circulating online. If you’ve ever wondered whether biostimulants, nitrogen enhancers, or “metabolic activators” actually work in real-world turfgrass or crop management, this breakdown is for you. I review the product’s marketing claims, examine the d...

In this episode of Turfgrass Epistemology, I sit down with Dr. Lee Miller of Purdue University, one of the leading experts in turfgrass pathology, to break down everything you need to know about turfgrass disease resistance, fungicide rotations, and accurate turf disease identification. Whether you manage golf course greens, sports fields, or home lawns, this conversation gives you the practical,...

In this video, I analyze the 2025 Zhang et al. study on how fungicide scheduling and bentgrass cultivar resistance interact to influence dollar spot control. This research provides some of the strongest evidence to date that curative, damage-threshold-based fungicide programs can dramatically reduce inputs—up to 78 percent in certain cases—when paired with disease-resistant bentgrass cultivars. I...

In this video, I break down one of the most influential papers ever written on turfgrass pathology: Walsh, Ikeda, and Boland’s 1999 review on the biology and management of dollar spot. This paper remains a foundational resource for understanding how the pathogen operates, why the disease is so persistent on cool-season turf, and which management strategies are supported by evidence rather than tra...

In this episode of Turfgrass Epistemology, I review a popular lawn-care website article and an accompanying YouTube video that teach homeowners how to interpret a soil test that is, in reality, scientifically invalid for making nutrient decisions. These resources look polished and authoritative, but the advice they provide is fundamentally flawed — and following it can lead to unnecessary product...

Not all scientific journals are created equal. Some exist to advance knowledge — others exist to collect publishing fees. In this episode of Turfgrass Epistemology, we explore how to tell the difference. I’ll walk through the refereed process and explain how it differs from standard peer review, why that distinction matters, and how the structure of editorial oversight determines the credibility o...

In this episode of Turfgrass Epistemology, we take a close look at one of the most frequently cited studies in turfgrass pathology — Golembiewski and Danneberger’s 1998 Agronomy Journal paper exploring how trinexapac-ethyl (TE) and nitrogen fertility influence the severity of dollar spot (Sclerotinia homoeocarpa) in creeping bentgrass. The researchers found that TE, a popular plant growth regulato...

In this episode, I sit down to talk about a topic that’s been at the heart of American higher education for more than a century — university extension. We’ll explore how extension began, why it was once the lifeblood of land-grant universities, and how the system that connected science to society is now quietly disappearing. Extension was created so universities could serve the public — not just b...

Can something as simple as mowing time really stop a turfgrass disease? In this episode of Turfgrass Epistemology, we look back at a landmark 1996 study by Williams, Powell, Vincelli, and Dougherty from the University of Kentucky — a paper that changed how superintendents think about dew, nitrogen, and dollar spot control. Dollar spot (Sclerotinia homoeocarpa) thrives on leaf moisture. Williams et...

In this video, I explore the history and current state of university turfgrass programs—from their rise during the post-war boom in golf, parks, and sports fields to their decline in recent decades. I explain how turfgrass faculty positions are created and filled, what factors lead to the loss of those positions, and why many programs are now disappearing altogether. I connect the dots between enr...