Turfgrass Epistemology

In this episode of Turfgrass Epistemology, I break down the peer-reviewed Crop Science article “Mowing Strategies and Dew Removal to Minimize Dollar Spot on Creeping Bentgrass” by Ellram, Horgan, and Hulke (2007). This study evaluates how mowing time, dew removal frequency, blade sharpness, and leaf wetness duration (LWD) influence dollar spot severity on creeping bentgrass fairways. I explain why mowing at 4:00 AM consistently reduced dollar spot compared to 10:00 AM, why daily dew removal outperformed alternate-day removal, and why dull mower blades did not increase disease despite common belief. The controlled-environment data also show lesion size increased dramatically as leaf wetness duration extended from 6 to 18 hours. If you manage creeping bentgrass, battle dollar spot, or want to better understand the role of irrigation timing, dew removal, and cultural disease control, this video connects classic research to modern integrated pest management strategies. Subscribe for more turfgrass disease management, dollar spot research, and evidence-based golf course agronomy discussions focused on how we know what we know. Become a member of Turfgrass Epistemology and support turfgrass research: www.youtube.com/@TurfgrassEpistemology/join Voicemail: 859-444-4234 Apple Podcast https://podcasts.apple.com/us/podcast/turfgrass-epistemology/id1717271379 Spotify Podcast https://open.spotify.com/show/1cTpdrChToeEFAOX9wkXFI iHeart Radio Podcast https://www.iheart.com/podcast/1323-turfgrass-epistemology-129043524/ Podbean https://turfgrassepistemology.podbean.com/ Online consulting Calendly.com/TravisShaddox Twitter Twitter.com/TravisShaddox Email TravisShaddox@gmail.com Turfgrass Programs and Extension Service Information: https://www.usna.usda.gov/assets/images/as_pdf_image/LandGrantColleges.pdf

In this episode of Turfgrass Epistemology, I discuss the Purdue Extension publication “Common Diseases on Cool-Season Lawns” (BP-218-W), a practical guide to identifying and managing diseases on Kentucky bluegrass and tall fescue. This publication outlines major lawn diseases including dollar spot, brown patch, Pythium blight, red thread, rust, summer patch, gray leaf spot, and leaf spot/melting out, while also emphasizing the critical distinction between biotic diseases and abiotic disorders such as compaction, drought, and nutrient stress. I explain why accurate diagnosis requires understanding host species, environmental conditions, and disease spread patterns—not just visual symptoms. If you manage cool-season lawns, advise homeowners, or work in turfgrass disease management, this video breaks down key takeaways from this guide and connects them to evidence-based lawn care practices. Subscribe for more turfgrass disease management, lawn care science, and evidence-based turfgrass education focused on how we know what we know. Subscribe for more turfgrass science, irrigation research, and evidence-based golf course management discussions focused on how we know what we know. #Turfgrass #SoilScience #LawnCare #GolfCourseManagement #TurfgrassScience #SoilFertility #CriticalThinking #TurfTok #TurfgrassEpistemology #EvidenceBased #LawnCareTips 📌 https://www.gofundme.com/f/TurfgrassEpistemology Thank you for being part of this community and for supporting evidence-based turfgrass science. Join Turfgrass Epistemology to get access to perks: https://www.youtube.com/channel/UC-UZnHkJhAmARDZ4YoHnc_A/join Voicemail: 859-444-4234 Apple Podcast https://podcasts.apple.com/us/podcast/turfgrass-epistemology/id1717271379 Spotify Podcast https://open.spotify.com/show/1cTpdrChToeEFAOX9wkXFI iHeart Radio Podcast https://www.iheart.com/podcast/1323-turfgrass-epistemology-129043524/ Podbean https://turfgrassepistemology.podbean.com/ Online consulting Calendly.com/TravisShaddox Twitter Twitter.com/TravisShaddox Email TravisShaddox@gmail.com Turfgrass Programs and Extension Service Information: https://www.usna.usda.gov/assets/images/as_pdf_image/LandGrantColleges.pdf Diagnostic Criteria for Turfgrass Bullshit Disorder:https://drive.google.com/file/d/1Y_GeVPQ237pzm0ImTP4eVij6I9D0PHPn/view

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 like Crenshaw increased disease pressure in blends, how resistant cultivars like L-93 suppressed dollar spot, and why overall disease levels in blends often reflected a compromise between the resistance levels of the individual components. The key takeaway: blending resistant and susceptible cultivars can significantly reduce dollar spot compared to planting a susceptible cultivar alone—but blends do not automatically create superior resistance across the board. If you manage creeping bentgrass putting greens or make decisions about cultivar selection, genetic diversity, and dollar spot management, this video breaks down what the data actually show and how blending fits into an evidence-based disease management strategy. Subscribe for more turfgrass science, cultivar performance research, and evidence-based golf course management discussions. Become a member of Turfgrass Epistemology and support turfgrass research: www.youtube.com/@TurfgrassEpistemology/join Voicemail: 859-444-4234 Apple Podcast https://podcasts.apple.com/us/podcast/turfgrass-epistemology/id1717271379 Spotify Podcast https://open.spotify.com/show/1cTpdrChToeEFAOX9wkXFI iHeart Radio Podcast https://www.iheart.com/podcast/1323-turfgrass-epistemology-129043524/ Podbean https://turfgrassepistemology.podbean.com/ Online consulting Calendly.com/TravisShaddox Twitter Twitter.com/TravisShaddox Email TravisShaddox@gmail.com Turfgrass Programs and Extension Service Information: https://www.usna.usda.gov/assets/images/as_pdf_image/LandGrantColleges.pdf

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 perennial ryegrass fairways. I explain how ET-based irrigation reduced water use by nearly 200%, how daily irrigation suppressed brown patch but increased dollar spot, and why irrigation strategy did not significantly influence crabgrass or dandelion populations. If you manage golf course fairways or make decisions about irrigation management, turfgrass disease control, and water conservation, this video connects classic research to modern turf management and integrated pest management strategies. Subscribe for more turfgrass science, irrigation research, and evidence-based golf course management discussions focused on how we know what we know. #Turfgrass #SoilScience #LawnCare #GolfCourseManagement #TurfgrassScience #SoilFertility #CriticalThinking #TurfTok #TurfgrassEpistemology #EvidenceBased #LawnCareTips 📌 https://www.gofundme.com/f/TurfgrassEpistemology Thank you for being part of this community and for supporting evidence-based turfgrass science. Join Turfgrass Epistemology to get access to perks: https://www.youtube.com/channel/UC-UZnHkJhAmARDZ4YoHnc_A/join Voicemail: 859-444-4234 Apple Podcast https://podcasts.apple.com/us/podcast/turfgrass-epistemology/id1717271379 Spotify Podcast https://open.spotify.com/show/1cTpdrChToeEFAOX9wkXFI iHeart Radio Podcast https://www.iheart.com/podcast/1323-turfgrass-epistemology-129043524/ Podbean https://turfgrassepistemology.podbean.com/ Online consulting Calendly.com/TravisShaddox Twitter Twitter.com/TravisShaddox Email TravisShaddox@gmail.com Turfgrass Programs and Extension Service Information: https://www.usna.usda.gov/assets/images/as_pdf_image/LandGrantColleges.pdf Diagnostic Criteria for Turfgrass Bullshit Disorder:https://drive.google.com/file/d/1Y_GeVPQ237pzm0ImTP4eVij6I9D0PHPn/view

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-based turfgrass science from marketing claims and social media advice. I clarify misunderstandings about nutrient ratios, iron applications, nitrogen programs, and disease suppression while explaining how to interpret research correctly. If you’re interested in soil fertility, turfgrass disease management, golf course agronomy, or lawn care best practices, this episode provides practical, research-driven answers to real questions from the field. Subscribe for more turfgrass science, critical thinking in lawn care, and evidence-based golf course management discussions that go deeper than quick tips and product hype. Become a member of Turfgrass Epistemology and support turfgrass research: www.youtube.com/@TurfgrassEpistemology/join Voicemail: 859-444-4234 Apple Podcast https://podcasts.apple.com/us/podcast/turfgrass-epistemology/id1717271379 Spotify Podcast https://open.spotify.com/show/1cTpdrChToeEFAOX9wkXFI iHeart Radio Podcast https://www.iheart.com/podcast/1323-turfgrass-epistemology-129043524/ Podbean https://turfgrassepistemology.podbean.com/ Online consulting Calendly.com/TravisShaddox Twitter Twitter.com/TravisShaddox Email TravisShaddox@gmail.com Turfgrass Programs and Extension Service Information: https://www.usna.usda.gov/assets/images/as_pdf_image/LandGrantColleges.pdf

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-reviewed research should be interpreted instead of relying on anecdotes, marketing claims, or social media shortcuts. This video focuses on critical thinking in turfgrass management, explaining how to evaluate advice, understand soil and tissue test results, and avoid common reasoning errors when making fertility and pest management decisions. If you’ve commented on a video, sent an email, or wondered whether advice you see online is actually supported by science, this episode is for you. Subscribe for evidence-based turfgrass content, long-form explanations, and practical discussions that go beyond soundbites and fertilizer folklore. 🔔 Subscribe for more evidence-based turfgrass content, scientific paper discussions, and long-form explanations that go beyond social media soundbites. #Turfgrass #SoilScience #LawnCare #GolfCourseManagement #TurfgrassScience #SoilFertility #CriticalThinking #TurfTok #TurfgrassEpistemology #EvidenceBased #LawnCareTips 📌 https://www.gofundme.com/f/TurfgrassEpistemology Thank you for being part of this community and for supporting evidence-based turfgrass science. Join Turfgrass Epistemology to get access to perks: https://www.youtube.com/channel/UC-UZnHkJhAmARDZ4YoHnc_A/join Voicemail: 859-444-4234 Apple Podcast https://podcasts.apple.com/us/podcast/turfgrass-epistemology/id1717271379 Spotify Podcast https://open.spotify.com/show/1cTpdrChToeEFAOX9wkXFI iHeart Radio Podcast https://www.iheart.com/podcast/1323-turfgrass-epistemology-129043524/ Podbean https://turfgrassepistemology.podbean.com/ Online consulting Calendly.com/TravisShaddox Twitter Twitter.com/TravisShaddox Email TravisShaddox@gmail.com Turfgrass Programs and Extension Service Information: https://www.usna.usda.gov/assets/images/as_pdf_image/LandGrantColleges.pdf Diagnostic Criteria for Turfgrass Bullshit Disorder:https://drive.google.com/file/d/1Y_GeVPQ237pzm0ImTP4eVij6I9D0PHPn/view

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 leaf spot development on creeping bentgrass and perennial ryegrass fairways. I explain why dollar spot was consistently more severe under dry, infrequently irrigated conditions, how soil moisture strongly influenced disease severity late in the season, and what this means for cultural disease management strategies on golf courses. The discussion also covers how chlorothalonil performance varied with irrigation regime, why paclobutrazol provided partial dollar spot suppression, and why wetting agents alone were unreliable for disease control. Most importantly, I explain how this paper reshapes the way we should think about water management as a disease driver, rather than viewing irrigation only through the lens of turf stress or playability. If you manage creeping bentgrass fairways, battle chronic dollar spot, or want an evidence-based explanation of how irrigation practices interact with fungicides and plant growth regulators, this video walks through what the data actually show—and how to apply it responsibly in modern turfgrass management. Subscribe for more turfgrass science discussions, classic paper reviews, and evidence-based explanations focused on how we know what we know in turf management. Don’t forget to like, share, and subscribe to stay updated on more science-driven insights! Become a member of Turfgrass Epistemology and support turfgrass research: www.youtube.com/@TurfgrassEpistemology/join Voicemail: 859-444-4234 Apple Podcast https://podcasts.apple.com/us/podcast/turfgrass-epistemology/id1717271379 Spotify Podcast https://open.spotify.com/show/1cTpdrChToeEFAOX9wkXFI iHeart Radio Podcast https://www.iheart.com/podcast/1323-turfgrass-epistemology-129043524/ Podbean https://turfgrassepistemology.podbean.com/ Online consulting Calendly.com/TravisShaddox Twitter Twitter.com/TravisShaddox Email TravisShaddox@gmail.com Turfgrass Programs and Extension Service Information: https://www.usna.usda.gov/assets/images/as_pdf_image/LandGrantColleges.pdf

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 volume influence dollar spot suppression on creeping bentgrass and annual bluegrass fairways. I explain the dose-dependent response observed across multiple locations, why 7-day reapplication intervals consistently outperformed 14-day intervals, and why spray water volume and tank-mixing with fertilizer had minimal impact on disease control. The discussion emphasizes what this research means for golf course superintendents looking to reduce fungicide reliance while avoiding phytotoxicity and unnecessary applications. Rather than treating iron sulfate as a cure-all, I place these results in the context of integrated dollar spot management, fungicide resistance concerns, and realistic expectations for non-fungicidal suppression strategies. If you manage fairways, evaluate iron programs, or want an evidence-based explanation of how liquid iron sulfate actually performs against dollar spot, this video breaks down what the data show—and how to apply it responsibly. Subscribe for more turfgrass science, peer-reviewed paper discussions, and evidence-based explanations focused on how we know what we know in turf management. 🔔 Subscribe for more evidence-based turfgrass content, scientific paper discussions, and long-form explanations that go beyond social media soundbites. #Turfgrass #SoilScience #LawnCare #GolfCourseManagement #TurfgrassScience #SoilFertility #CriticalThinking #TurfTok #TurfgrassEpistemology #EvidenceBased #LawnCareTips 📌 https://www.gofundme.com/f/TurfgrassEpistemology Thank you for being part of this community and for supporting evidence-based turfgrass science. Join Turfgrass Epistemology to get access to perks: https://www.youtube.com/channel/UC-UZnHkJhAmARDZ4YoHnc_A/join Voicemail: 859-444-4234 Apple Podcast https://podcasts.apple.com/us/podcast/turfgrass-epistemology/id1717271379 Spotify Podcast https://open.spotify.com/show/1cTpdrChToeEFAOX9wkXFI iHeart Radio Podcast https://www.iheart.com/podcast/1323-turfgrass-epistemology-129043524/ Podbean https://turfgrassepistemology.podbean.com/ Online consulting Calendly.com/TravisShaddox Twitter Twitter.com/TravisShaddox Email TravisShaddox@gmail.com Turfgrass Programs and Extension Service Information: https://www.usna.usda.gov/assets/images/as_pdf_image/LandGrantColleges.pdf Diagnostic Criteria for Turfgrass Bullshit Disorder:https://drive.google.com/file/d/1Y_GeVPQ237pzm0ImTP4eVij6I9D0PHPn/view

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 greens. The study evaluates whether ferrous sulfate itself, or its individual components iron and sulfur, are responsible for observed dollar spot suppression. Using both field trials on USGA-spec creeping bentgrass greens and controlled in-vitro assays, the authors show that ferrous sulfate consistently reduced dollar spot severity, while elemental sulfur had no effect and chelated iron produced inconsistent results across years. In this video, I walk through the experimental design, disease response data, and turf quality results, with particular emphasis on what actually drives suppression. The findings demonstrate that ferrous sulfate behaves differently than iron chelates and sulfur, and that the disease response cannot be explained simply by nutrient sufficiency, sulfur acidification, or color response. Instead, the evidence points toward a direct fungistatic or fungitoxic effect of ferrous sulfate on the dollar spot pathogen at sufficiently high concentrations. I also explain why the in-vitro results matter for interpreting field performance. The paper shows that low iron concentrations can actually stimulate fungal growth, while very high concentrations suppress mycelial development across a range of pH levels. This nuance is critical, because it explains why iron programs can sometimes appear inconsistent or even counterproductive when rates, formulations, or application frequency are poorly understood. Throughout the discussion, I place this study in the broader context of dollar spot management, fungicide resistance, and integrated pest management. Ferrous sulfate is not presented as a replacement for fungicides, nor as a fertility shortcut, but as a biologically active compound that can partially suppress disease under specific conditions—while also carrying real risks if misused. This episode is especially relevant for golf course superintendents, turfgrass researchers, and advanced turf managers who are considering iron-based programs for dollar spot suppression and want to understand what the science actually supports, what it does not, and why oversimplified interpretations can lead to poor decisions. Subscribe for more long-form turfgrass science discussions, peer-reviewed paper breakdowns, and clear explanations focused on how we know what we know in turfgrass management. Don’t forget to like, share, and subscribe to stay updated on more science-driven insights! Become a member of Turfgrass Epistemology and support turfgrass research: www.youtube.com/@TurfgrassEpistemology/join Voicemail: 859-444-4234 Apple Podcast https://podcasts.apple.com/us/podcast/turfgrass-epistemology/id1717271379 Spotify Podcast https://open.spotify.com/show/1cTpdrChToeEFAOX9wkXFI iHeart Radio Podcast https://www.iheart.com/podcast/1323-turfgrass-epistemology-129043524/ Podbean https://turfgrassepistemology.podbean.com/ Online consulting Calendly.com/TravisShaddox Twitter Twitter.com/TravisShaddox Email TravisShaddox@gmail.com Turfgrass Programs and Extension Service Information: https://www.usna.usda.gov/assets/images/as_pdf_image/LandGrantColleges.pdf

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 suppression on golf course turf. The study combines multi-site field trials with controlled in-vitro experiments to examine how ferrous sulfate rate influences dollar spot severity on creeping bentgrass fairways and putting greens, as well as how different Clarireedia isolates respond to increasing iron concentrations in culture. I walk through both components of the research, explaining what the data show about rate response, diminishing returns, and why previously recommended rates may be higher than necessary for meaningful disease suppression. A major focus of the discussion is the nonlinear nature of the response. The results demonstrate that approximately 25–26 kg ha⁻¹ of ferrous sulfate was sufficient to achieve about 50% dollar spot suppression, with much smaller gains at higher rates and increased risk of turf injury under stress conditions. I explain why this matters for real-world management and how these findings challenge the tendency to assume that “more is better” when it comes to iron applications. I also discuss the in-vitro portion of the study, which shows that ferrous sulfate has a direct fungitoxic effect on Clarireedia, but that the concentration required to suppress mycelial growth varies by isolate and by host type. This section is important for understanding why field performance can be inconsistent and why pathogen biology, management history, and turf system context all influence outcomes. Throughout the video, I place this paper within the broader dollar spot literature and explain what it does—and does not—justify in practice. Ferrous sulfate is not a replacement for fungicides, nor is it a magic bullet, but it can function as a partial suppression tool within an integrated disease management program when its limitations are understood. This episode is especially relevant for golf course superintendents, turfgrass researchers, and advanced turf managers who are evaluating iron-based programs for dollar spot control and want to separate evidence-based conclusions from oversimplified recommendations. Subscribe for more long-form turfgrass science discussions, peer-reviewed paper breakdowns, and clear explanations focused on how we know what we know in turfgrass management. 🔔 Subscribe for more evidence-based turfgrass content, scientific paper discussions, and long-form explanations that go beyond social media soundbites. #Turfgrass #SoilScience #LawnCare #GolfCourseManagement #TurfgrassScience #SoilFertility #CriticalThinking #TurfTok #TurfgrassEpistemology #EvidenceBased #LawnCareTips 📌 https://www.gofundme.com/f/TurfgrassEpistemology Thank you for being part of this community and for supporting evidence-based turfgrass science. Join Turfgrass Epistemology to get access to perks: https://www.youtube.com/channel/UC-UZnHkJhAmARDZ4YoHnc_A/join Voicemail: 859-444-4234 Apple Podcast https://podcasts.apple.com/us/podcast/turfgrass-epistemology/id1717271379 Spotify Podcast https://open.spotify.com/show/1cTpdrChToeEFAOX9wkXFI iHeart Radio Podcast https://www.iheart.com/podcast/1323-turfgrass-epistemology-129043524/ Podbean https://turfgrassepistemology.podbean.com/ Online consulting Calendly.com/TravisShaddox Twitter Twitter.com/TravisShaddox Email TravisShaddox@gmail.com Turfgrass Programs and Extension Service Information: https://www.usna.usda.gov/assets/images/as_pdf_image/LandGrantColleges.pdf Diagnostic Criteria for Turfgrass Bullshit Disorder:https://drive.google.com/file/d/1Y_GeVPQ237pzm0ImTP4eVij6I9D0PHPn/view

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 suppress dollar spot without relying solely on fungicides?  The study evaluated repeated foliar nitrogen applications on creeping bentgrass putting greens across multiple years and locations, using a spoon-feeding approach that mirrors how many golf course superintendents manage fertility today. I walk through the experimental design, nitrogen rates, nitrogen sources, and how dollar spot severity responded over time. A major focus of the discussion is why only the highest nitrogen rate consistently reduced dollar spot severity, while lower, more typical spoon-feeding rates provided little to no disease suppression. In this video, I explain what the results actually show—and just as importantly, what they do not show. While nitrogen clearly influenced dollar spot development, the rate required to achieve meaningful suppression raises practical, agronomic, and environmental concerns. I also discuss how nitrogen source had minimal and inconsistent effects, why foliar nitrogen concentration may be more informative than application rate alone, and how these findings fit into integrated pest management strategies rather than stand-alone fertility “solutions.” This episode is especially relevant for golf course superintendents, turfgrass researchers, and advanced turf managers who hear that “more nitrogen reduces dollar spot” without adequate context. The data demonstrate that the relationship between nitrogen and disease is real but non-linear, highly rate-dependent, and constrained by tradeoffs involving growth, thatch accumulation, environmental risk, and secondary disease pressure. As always, the goal of this discussion is evidence-based interpretation, not fertilizer folklore or oversimplified recommendations. If you are making fertility decisions to manage dollar spot on creeping bentgrass putting greens, this video will help you better understand how nitrogen fits into the bigger disease management picture. Subscribe for more long-form turfgrass science discussions, peer-reviewed paper breakdowns, and clear explanations focused on how we know what we know in turfgrass management. Don’t forget to like, share, and subscribe to stay updated on more science-driven insights! Become a member of Turfgrass Epistemology and support turfgrass research: www.youtube.com/@TurfgrassEpistemology/join Voicemail: 859-444-4234 Apple Podcast https://podcasts.apple.com/us/podcast/turfgrass-epistemology/id1717271379 Spotify Podcast https://open.spotify.com/show/1cTpdrChToeEFAOX9wkXFI iHeart Radio Podcast https://www.iheart.com/podcast/1323-turfgrass-epistemology-129043524/ Podbean https://turfgrassepistemology.podbean.com/ Online consulting Calendly.com/TravisShaddox Twitter Twitter.com/TravisShaddox Email TravisShaddox@gmail.com Turfgrass Programs and Extension Service Information: https://www.usna.usda.gov/assets/images/as_pdf_image/LandGrantColleges.pdf

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 relies on the idea that soils must be managed toward specific “ideal” cation percentage ratios to achieve productivity. In this video, I explain why base saturation is not a causal driver of turfgrass performance, why the concept persists despite decades of contradictory evidence, and how it functions more as a marketing narrative than a scientifically defensible soil fertility framework in turf systems. I also discuss how focusing on cation ratios distracts from the variables that actually matter, such as nutrient sufficiency, cation exchange capacity, soil texture, and plant demand. I also critique the soil pH diagram used in these videos, which is frequently circulated across agriculture and lawn care media. I explain why this diagram is oversimplified, misleading, and biologically inaccurate, and why it should not be used to diagnose nutrient deficiencies or guide fertilizer decisions. Rather than nutrients abruptly “locking up” outside narrow pH bands, I explain how nutrient availability is continuous, soil-specific, and governed by chemistry, mineralogy, and management history—not cartoon gradients. Throughout the video, I walk through why these ideas are especially problematic in turfgrass systems, where soils are often sand-based, heavily modified, intensively managed, and fundamentally different from agronomic field soils. I explain how misuse of base saturation theory and pH diagrams leads to unnecessary amendments, wasted money, and false confidence—while offering no predictive power for turf response. This episode is intended for golf course superintendents, turfgrass scientists, lawn care professionals, and homeowners who want evidence-based soil fertility interpretation rather than tradition, authority, or marketing-driven dogma. The goal is not to argue opinions, but to explain why certain ideas fail scientifically, why they continue to spread, and how to replace them with better reasoning. If you’ve ever been told your soil is “out of balance,” that your calcium-to-magnesium ratio is wrong, or that nutrients are “locked up” based on a single pH chart, this video will help you understand why those claims persist—and why they don’t hold up under scrutiny. Subscribe for long-form turfgrass science discussions, critical analysis of common soil fertility claims, and clear explanations focused on how we know what we know in turfgrass management. Subscribe for more long-form turfgrass science discussions, peer-reviewed paper breakdowns, and practical explanations focused on how we know what we know in turfgrass management. 🔔 Subscribe for more evidence-based turfgrass content, scientific paper discussions, and long-form explanations that go beyond social media soundbites. #Turfgrass #SoilScience #LawnCare #GolfCourseManagement #TurfgrassScience #SoilFertility #CriticalThinking #TurfTok #TurfgrassEpistemology #EvidenceBased #LawnCareTips 📌 https://www.gofundme.com/f/TurfgrassEpistemology Thank you for being part of this community and for supporting evidence-based turfgrass science. Join Turfgrass Epistemology to get access to perks: https://www.youtube.com/channel/UC-UZnHkJhAmARDZ4YoHnc_A/join Voicemail: 859-444-4234 Apple Podcast https://podcasts.apple.com/us/podcast/turfgrass-epistemology/id1717271379 Spotify Podcast https://open.spotify.com/show/1cTpdrChToeEFAOX9wkXFI iHeart Radio Podcast https://www.iheart.com/podcast/1323-turfgrass-epistemology-129043524/ Podbean https://turfgrassepistemology.podbean.com/ Online consulting Calendly.com/TravisShaddox Twitter Twitter.com/TravisShaddox Email TravisShaddox@gmail.com Turfgrass Programs and Extension Service Information: https://www.usna.usda.gov/assets/images/as_pdf_image/LandGrantColleges.pdf Diagnostic Criteria for Turfgrass Bullshit Disorder:https://drive.google.com/file/d/1Y_GeVPQ237pzm0ImTP4eVij6I9D0PHPn/view

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 that increasing potassium rates consistently increased dollar spot severity under the conditions tested. This directly challenges the common assumption that potassium fertilization automatically improves stress tolerance or reduces disease pressure in turfgrass systems. In the video, I explain the experimental design, including potassium and nitrogen rate treatments, mat layer and leaf tissue measurements, and how disease severity was quantified over time. I also discuss why potassium behaved differently than many turf managers expect, and how disease response depended on antecedent potassium levels in both the mat layer and plant tissue. This discussion emphasizes the importance of context in fertility management. Potassium is an essential nutrient, but its relationship with turfgrass disease is not linear or universally beneficial. The results highlight why relying on generalized nutrient “rules” without soil and tissue data can lead to unintended consequences in disease management programs. If you manage golf course putting greens, work in turfgrass research, or make fertility decisions based on soil tests and tissue analysis, this episode provides critical insight into how potassium, nitrogen, and dollar spot interact in real turf systems. The goal is not to discourage potassium use, but to encourage evidence-based decision-making grounded in measured nutrient status rather than assumptions. Subscribe for more long-form turfgrass science discussions, peer-reviewed paper breakdowns, and practical explanations focused on how we know what we know in turfgrass management. 🔔 Subscribe for more evidence-based turfgrass content, scientific paper discussions, and long-form explanations that go beyond social media soundbites. #Turfgrass #SoilScience #LawnCare #GolfCourseManagement #TurfgrassScience #SoilFertility #CriticalThinking #TurfTok #TurfgrassEpistemology #EvidenceBased #LawnCareTips 📌 https://www.gofundme.com/f/TurfgrassEpistemology Thank you for being part of this community and for supporting evidence-based turfgrass science. Join Turfgrass Epistemology to get access to perks: https://www.youtube.com/channel/UC-UZnHkJhAmARDZ4YoHnc_A/join Voicemail: 859-444-4234 Apple Podcast https://podcasts.apple.com/us/podcast/turfgrass-epistemology/id1717271379 Spotify Podcast https://open.spotify.com/show/1cTpdrChToeEFAOX9wkXFI iHeart Radio Podcast https://www.iheart.com/podcast/1323-turfgrass-epistemology-129043524/ Podbean https://turfgrassepistemology.podbean.com/ Online consulting Calendly.com/TravisShaddox Twitter Twitter.com/TravisShaddox Email TravisShaddox@gmail.com Turfgrass Programs and Extension Service Information: https://www.usna.usda.gov/assets/images/as_pdf_image/LandGrantColleges.pdf Diagnostic Criteria for Turfgrass Bullshit Disorder:https://drive.google.com/file/d/1Y_GeVPQ237pzm0ImTP4eVij6I9D0PHPn/view

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 where confusion often arises when science meets social media. I address trends I’ve seen across platforms, clarify misunderstandings, and explain why certain claims persist despite decades of research. Topics discussed include: Common turfgrass myths repeated in social media comments Misinterpretations of soil tests, nutrients, and fertilizers Questions about phosphorus, potassium, nitrogen, and soil biology The influence of marketing and anecdote vs. peer-reviewed science Why short-form content (TikTok, reels, shorts) often oversimplifies turf science How to develop critical thinking skills when evaluating turfgrass advice online This episode is not about calling people out—it’s about slowing down, adding context, and explaining how we know what we know in turfgrass science. Whether you’re a golf course superintendent, lawn care operator, researcher, or homeowner trying to make better management decisions, this discussion is designed to help you separate evidence from noise. If you’ve emailed me, commented on YouTube, or left a TikTok comment in 2025, there’s a good chance your question—or one just like it—is addressed here. 🔔 Subscribe for more evidence-based turfgrass content, scientific paper discussions, and long-form explanations that go beyond social media soundbites. #Turfgrass #SoilScience #LawnCare #GolfCourseManagement #TurfgrassScience #SoilFertility #CriticalThinking #TurfTok #TurfgrassEpistemology #EvidenceBased #LawnCareTips 📌 https://www.gofundme.com/f/TurfgrassEpistemology Thank you for being part of this community and for supporting evidence-based turfgrass science. Join Turfgrass Epistemology to get access to perks: https://www.youtube.com/channel/UC-UZnHkJhAmARDZ4YoHnc_A/join Voicemail: 859-444-4234 Apple Podcast https://podcasts.apple.com/us/podcast/turfgrass-epistemology/id1717271379 Spotify Podcast https://open.spotify.com/show/1cTpdrChToeEFAOX9wkXFI iHeart Radio Podcast https://www.iheart.com/podcast/1323-turfgrass-epistemology-129043524/ Podbean https://turfgrassepistemology.podbean.com/ Online consulting Calendly.com/TravisShaddox Twitter Twitter.com/TravisShaddox Email TravisShaddox@gmail.com Turfgrass Programs and Extension Service Information: https://www.usna.usda.gov/assets/images/as_pdf_image/LandGrantColleges.pdf Diagnostic Criteria for Turfgrass Bullshit Disorder:https://drive.google.com/file/d/1Y_GeVPQ237pzm0ImTP4eVij6I9D0PHPn/view

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, “Effect of Phosphite Rate and Source on Cyanobacteria Colonization of Putting Green Turf,” is one of the most frequently cited studies on this topic. In this conversation, we explore how phosphite differs from phosphate, why cyanobacteria respond differently to these compounds, and how phosphite applications can reduce algal crusting without relying solely on traditional fungicides  This discussion covers: How phosphite suppresses cyanobacteria colonization on creeping bentgrass putting greens Differences between phosphite vs. phosphate in turf systems Optimal phosphite application rates that balance efficacy and phytotoxicity risk Why product source and formulation matter less than active ingredient rate Practical implications for algae management programs on golf greens How this research fits into modern integrated turfgrass management If you manage putting greens, work in turfgrass research, or want an evidence-based explanation of phosphite products that cuts through anecdote and advertising, this episode provides critical context straight from the study’s lead author. 📄 Research discussed: Inguagiato, J.C., Kaminski, J.E., & Lulis, T.T. (2017). Effect of Phosphite Rate and Source on Cyanobacteria Colonization of Putting Green Turf. Crop Science 57: S-274–S-284. 🔔 Subscribe for more science-driven turfgrass discussions, paper reviews with authors, and critical analysis of common turf management claims. #TurfgrassScience #GolfCourseManagement #Phosphite #Cyanobacteria #PuttingGreens #TurfgrassResearch #SoilScience #EvidenceBasedTurf #TurfgrassEpistemology 📌 https://www.gofundme.com/f/TurfgrassEpistemology Thank you for being part of this community and for supporting evidence-based turfgrass science. Join Turfgrass Epistemology to get access to perks: https://www.youtube.com/channel/UC-UZnHkJhAmARDZ4YoHnc_A/join Voicemail: 859-444-4234 Apple Podcast https://podcasts.apple.com/us/podcast/turfgrass-epistemology/id1717271379 Spotify Podcast https://open.spotify.com/show/1cTpdrChToeEFAOX9wkXFI iHeart Radio Podcast https://www.iheart.com/podcast/1323-turfgrass-epistemology-129043524/ Podbean https://turfgrassepistemology.podbean.com/ Online consulting Calendly.com/TravisShaddox Twitter Twitter.com/TravisShaddox Email TravisShaddox@gmail.com Turfgrass Programs and Extension Service Information: https://www.usna.usda.gov/assets/images/as_pdf_image/LandGrantColleges.pdf Diagnostic Criteria for Turfgrass Bullshit Disorder:https://drive.google.com/file/d/1Y_GeVPQ237pzm0ImTP4eVij6I9D0PHPn/view

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 respectfully disagree Glaring omissions and what I believe should have been addressed My own take: what’s convincing, what needs more nuance 💡 Why this matters: Discussions like this are important — not just to critique others, but to encourage deeper thinking and accountability. If you’ve seen the original video: I invite you to watch this, think along with me, and decide for yourself what holds up. 👇 Join the conversation: Do you agree or disagree with my take? Did I miss anything? What would you add? Let me know your thoughts in the comments — I read them all 🙂 🔔 Don’t forget to like, subscribe, and turn on notifications if you want more content like this. 🎓 Turfgrass Epistemology — How do we know what we know? 📌 https://www.gofundme.com/f/TurfgrassEpistemology Thank you for being part of this community and for supporting evidence-based turfgrass science. Join Turfgrass Epistemology to get access to perks: https://www.youtube.com/channel/UC-UZnHkJhAmARDZ4YoHnc_A/join Voicemail: 859-444-4234 Apple Podcast https://podcasts.apple.com/us/podcast/turfgrass-epistemology/id1717271379 Spotify Podcast https://open.spotify.com/show/1cTpdrChToeEFAOX9wkXFI iHeart Radio Podcast https://www.iheart.com/podcast/1323-turfgrass-epistemology-129043524/ Podbean https://turfgrassepistemology.podbean.com/ Online consulting Calendly.com/TravisShaddox Twitter Twitter.com/TravisShaddox Email TravisShaddox@gmail.com Turfgrass Programs and Extension Service Information: https://www.usna.usda.gov/assets/images/as_pdf_image/LandGrantColleges.pdf Diagnostic Criteria for Turfgrass Bullshit Disorder:https://drive.google.com/file/d/1Y_GeVPQ237pzm0ImTP4eVij6I9D0PHPn/view

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 grisea) epidemics in perennial ryegrass managed under golf-course conditions. I walk through the methods, results, and implications of the research, and I discuss how the findings align—or don’t align—with common industry assumptions twenty years later. 🔬 Topics I cover in the review: The study design and why the researchers chose fairway- and rough-height mowing How N rates (0, 36.6, and 73.2 kg N ha⁻¹ per month) influenced GLS severity Why mowing height had less effect on disease than expected Environmental conditions that shaped the epidemic What turf managers can actually take away from this paper How these results compare to modern GLS observations in perennial ryegrass 💡 Why this article matters today: Gray leaf spot remains one of the most destructive diseases of perennial ryegrass on golf courses. Understanding how cultural practices influence disease severity is still essential for developing integrated, evidence-based management programs. This paper is a cornerstone in that conversation—and it still sparks debate. 👇 Join the discussion: Do you agree with how the authors interpreted their data? Have you observed different mowing-height effects in your region? Should N programs be modified during GLS-prone months? Share your thoughts in the comments. Critical evaluation of research—new and old—is how we advance turfgrass science and avoid assumptions that fail in the field. If you enjoy evidence-based turfgrass breakdowns, hit LIKE and SUBSCRIBE. Become a member of Turfgrass Epistemology and support turfgrass research: www.youtube.com/@TurfgrassEpistemology/join Voicemail: 859-444-4234 Apple Podcast https://podcasts.apple.com/us/podcast/turfgrass-epistemology/id1717271379 Spotify Podcast https://open.spotify.com/show/1cTpdrChToeEFAOX9wkXFI iHeart Radio Podcast https://www.iheart.com/podcast/1323-turfgrass-epistemology-129043524/ Podbean https://turfgrassepistemology.podbean.com/ Online consulting Calendly.com/TravisShaddox Twitter Twitter.com/TravisShaddox Email TravisShaddox@gmail.com Turfgrass Programs and Extension Service Information: https://www.usna.usda.gov/assets/images/as_pdf_image/LandGrantColleges.pdf

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 data presented in the official RDX-N brochure, and explain what the science really says about nitrogen uptake, nitrogen metabolism, and plant physiology. But this video is more than a review of one product—it's a lesson in how to evaluate agronomic claims using critical thinking and epistemology. When you understand how knowledge is justified, you’re better equipped to: • Identify misleading or unproven claims • Recognize when data is incomplete, selective, or irrelevant • Avoid being persuaded by marketing language • Make informed decisions based on reliable evidence In turfgrass, agriculture, and lawn care, new products appear constantly—each claiming to increase yields, improve nitrogen efficiency, reduce inputs, or boost plant health. Without strong critical thinking skills, it’s easy to be misled. Epistemology—the study of how we know what we know—helps protect you when you’re confronted with products, technologies, or scientific claims you’ve never heard of. By the end of this video, you’ll understand: • What RDX-N claims to do • Whether those claims are supported by high-quality evidence • How to assess scientific credibility in turfgrass and crop management • How to apply critical thinking when evaluating any agronomic product If you’re a turfgrass manager, agronomist, sports field manager, lawn care professional, or scientifically curious homeowner, this channel will help you make smarter, evidence-driven decisions. Subscribe to Turfgrass Epistemology for more videos on turfgrass science, nitrogen management, soil fertility, agronomy, and the critical thinking skills needed to navigate misinformation in the industry. 🎓 Turfgrass Epistemology — How do we know what we know? 📌 https://www.gofundme.com/f/TurfgrassEpistemology Thank you for being part of this community and for supporting evidence-based turfgrass science. Join Turfgrass Epistemology to get access to perks: https://www.youtube.com/channel/UC-UZnHkJhAmARDZ4YoHnc_A/join Voicemail: 859-444-4234 Apple Podcast https://podcasts.apple.com/us/podcast/turfgrass-epistemology/id1717271379 Spotify Podcast https://open.spotify.com/show/1cTpdrChToeEFAOX9wkXFI iHeart Radio Podcast https://www.iheart.com/podcast/1323-turfgrass-epistemology-129043524/ Podbean https://turfgrassepistemology.podbean.com/ Online consulting Calendly.com/TravisShaddox Twitter Twitter.com/TravisShaddox Email TravisShaddox@gmail.com Turfgrass Programs and Extension Service Information: https://www.usna.usda.gov/assets/images/as_pdf_image/LandGrantColleges.pdf Diagnostic Criteria for Turfgrass Bullshit Disorder:https://drive.google.com/file/d/1Y_GeVPQ237pzm0ImTP4eVij6I9D0PHPn/view

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, science-based guidance needed to protect your turf from common and emerging diseases. We explore what disease resistance in turfgrass truly means, why resistance develops, and how environmental conditions and management practices influence disease pressure. Dr. Miller explains how to design effective fungicide rotation programs, how to avoid resistance through proper FRAC group management, and how to choose the right mode of action at the right time of year. If you’re looking for evidence-based turfgrass management, best practices for fungicide use, or expert insights into turf disease diagnostics, this video delivers the tools you need. Subscribe for more science-driven conversations on turfgrass health, management, and critical thinking. 🎓 Turfgrass Epistemology — How do we know what we know? 📌 https://www.gofundme.com/f/TurfgrassEpistemology Thank you for being part of this community and for supporting evidence-based turfgrass science. Join Turfgrass Epistemology to get access to perks: https://www.youtube.com/channel/UC-UZnHkJhAmARDZ4YoHnc_A/join Voicemail: 859-444-4234 Apple Podcast https://podcasts.apple.com/us/podcast/turfgrass-epistemology/id1717271379 Spotify Podcast https://open.spotify.com/show/1cTpdrChToeEFAOX9wkXFI iHeart Radio Podcast https://www.iheart.com/podcast/1323-turfgrass-epistemology-129043524/ Podbean https://turfgrassepistemology.podbean.com/ Online consulting Calendly.com/TravisShaddox Twitter Twitter.com/TravisShaddox Email TravisShaddox@gmail.com Turfgrass Programs and Extension Service Information: https://www.usna.usda.gov/assets/images/as_pdf_image/LandGrantColleges.pdf Diagnostic Criteria for Turfgrass Bullshit Disorder:https://drive.google.com/file/d/1Y_GeVPQ237pzm0ImTP4eVij6I9D0PHPn/view

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 explain how the researchers designed the field trials, what the low damage threshold means in practice, how 24-hour and next-application-day schedules performed differently, and why resistant cultivars such as Declaration produced such large savings without sacrificing control. I also discuss how inoculation affected disease pressure, why susceptible cultivars behaved differently, and what this means for superintendents trying to reduce fungicide use while maintaining high-quality fairways. If you want a clear, evidence-based explanation of how timing, cultivar resistance, and disease pressure shape fungicide performance, this video brings the science into focus. 🎓 Turfgrass Epistemology — How do we know what we know? 📌 https://www.gofundme.com/f/TurfgrassEpistemology Thank you for being part of this community and for supporting evidence-based turfgrass science. Join Turfgrass Epistemology to get access to perks: https://www.youtube.com/channel/UC-UZnHkJhAmARDZ4YoHnc_A/join Voicemail: 859-444-4234 Apple Podcast https://podcasts.apple.com/us/podcast/turfgrass-epistemology/id1717271379 Spotify Podcast https://open.spotify.com/show/1cTpdrChToeEFAOX9wkXFI iHeart Radio Podcast https://www.iheart.com/podcast/1323-turfgrass-epistemology-129043524/ Podbean https://turfgrassepistemology.podbean.com/ Online consulting Calendly.com/TravisShaddox Twitter Twitter.com/TravisShaddox Email TravisShaddox@gmail.com Turfgrass Programs and Extension Service Information: https://www.usna.usda.gov/assets/images/as_pdf_image/LandGrantColleges.pdf Diagnostic Criteria for Turfgrass Bullshit Disorder:https://drive.google.com/file/d/1Y_GeVPQ237pzm0ImTP4eVij6I9D0PHPn/view