The Doublecut with Micah Woods

I go back five years to another video showing ball reaction on greens topdressed once that year. 

Calcium is an essential element that is almost never required as fertilizer for turfgrass. This episodes explains how mass flow of Ca in the soil water creates an accumulation of Ca at the root surface.

The KBC News TV station did a profile of Keya GC greenkeeper Andrew McDaniel. Watch that (with an English language soundtrack, if necessary) and hear about the driest summer in at least 40 years (I didn't look back farther than that).

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I discussed grass responding to P at establishment, but not at maturity, as a function of soil P combined with rootzone volume. 

Posts discussed are:

The topic of nutrient availability and extractable vs. exchangeable vs. available nutrients used to come up a lot, and I'm glad I haven't been asked this question as frequently in recent years. Fortunately, I have a long list of blog posts about this topic, and a good starting point is the one reviewed in this episode : https://www.asianturfgrass.com/post/its-not-really-about-extractable-or-available/

This episode discusses Grime's definition of stress as "external constraints which limit the rate of dry matter production" and how this is related to nutrient supply/demand/requirement for fine turfgrass.

I looked at sand particle sizes at the top of putting green rootzones, and compared those particle sizes to what is in the sand topdressing. The average results of this analysis are presented in this episode.

I looked at the temperatures and dew points for a range of cities around the world during the first month of the most recent meteorological summer. June 2026 in the northern hemisphere, and December 2025 in the southern.

The blog post discussed is: https://www.asianturfgrass.com/post/first-month-of-summer-dew-point-depression/

Also see the day in that month with the highest average dew point: https://www.paceturf.org/gallery/detail/first-month-of-summer-2026-maximum-dew-point

The firmness of putting greens varies with the surface organic material. More organic material in the top 2 cm (0.8 inches), and greens are softer. I discuss terminology, the relationship between firmness and organic material, and what you can do about this.

I've updated my recommendation for the sand quantity to apply for every unit of clipping volume harvested, if your goal is to keep surface organic material constant. Bjarni and I discussed topdressing by this method and the new equation that finds this sand amount.

This is about partitioning the growth flush after a rain. What's causing that growth flush? I made some calculations, using New Forest GC in the UK as an example. The increased soil water content from a 20 mm rain, in this example, would increase daily clipping volume from 10 mL/m2 to 22 mL/m2, a 12 mL increase.

It sounds counterintuitive at first, that you can maintain a lower average water content in the soil, and a higher air content in the soil, by applying irrigation every day. Once upon a time, I thought the way to keep soils drier and with more air was to implement deep and infrequent irrigation. 

Brian Whitlark joined me to talk about sand topdressing of putting greens and especially about sand amounts.

High maintenance turf often requires a high disturbance and high stress environment. Grime's CSR theory says there are "no viable strategies" for plants in such an environment. I discuss the implications of this.

Blog post discussed is https://www.asianturfgrass.com/post/competition-stress-disturbance/

T-Jay Creamer is the golf course superintendent at Olympic View Golf Club on Vancouver Island. He's seen a steady decrease in OM2 in response to his N and sand rates, along with substantially more consistent OM2 values green to green. We discussed the results and what he does to accomplish this.

Jason Haines is the Links Superintendent at Cabot Cape Breton. We had a wide ranging conversation about blog posts from 2025, a new #MLSN article,  controlling snow mold, things that look easy but aren't easy, and more.

Stewart Naugler is the Director of Agronomy at Loraloma in Texas. We talked about zoysiagrass as a golfing surface, playability, and maintenance requirements.

We started by discussion my "Achieving the warm-season links" article, available here: https://www.asianturfgrass.com/publication/woods-2013-gca/

Read more about all kinds of turfgrass topics at https://www.asianturfgrass.com/
Find a suite of decision-making tools at https://www.paceturf.org/
Get free ATC newsletters at https://www.asianturfgrass.com/newsletter/

Thatch and mat at the top of turfgrass rootzones are removed from soils prior to testing for soil organic matter. Total organic material (OM246) testing is designed to measure the soil organic matter plus the thatch and mat.

The blog post discussed is https://www.asianturfgrass.com/post/organic-matter-and-screens/

Read more about all kinds of turfgrass topics at https://www.asianturfgrass.com/
Find a suite of decision-making tools at https://www.paceturf.org/
Get free ATC newsletters at https://www.asianturfgrass.com/newsletter/

This gives an overview of the seminars I presented at the GCSAA Conference in 2026 and discusses updated PACE Turf site analyses of photosynthetically active radiation (PAR).

Maggie Reiter joined me to discuss her "Finding Turf Twitter" analysis, her analysis of current turf research topics at the ASA-CSSA-SSSA meetings, tropical grasses, and irrigation water requirements.

We discussed: 

Scientific writing is not always as clear as this. There's an article I really enjoyed that stated right at the start, in the abstract, that core aeration "might not be worth doing." 

Dr. Kaminski joined me from his sabbatical in Australia to discuss flights, turf photos, and what he's been doing on his sabbatical.

This episode answers that question with how I recommend doing this. For today, we don't need to add N. But the soil nutrient levels decrease with time, we can predict how much the grass will use, and I make fertilizer recommendations looking into the future, rather than waiting to test again before making a decision to apply. 

Joe Gulotti joined me to give the doublecut treatment to the top posts of 2025 on the ATC blog, plus a bit of holiday extravaganza.

When grass clippings are returned to the turf, the quantity of nutrients required as fertilizer is decreased. In this episode I discuss how I handle the clippings returned situation.

The #MLSN method for nutrient recommendations involves an MLSN value that the soil is not supposed to drop below. But what does this value mean, when converted from the usual units of ppm (mg/kg) to how many years it would take grass to use that much of the element? 

This episode explains the steps I'd take to change greens from too hard (surface hardness and ball bounce, not hard as in difficulty) to just right. It follows that the opposite steps could be taken to move greens from too soft to just right.

The blog post discussed is https://www.asianturfgrass.com/post/to-keep-green-soft/
The ball bounce video from Dan Dinelli is at https://youtu.be/r1LV77z_Ziw

Read more about all kinds of turfgrass topics at https://www.asianturfgrass.com/
Find a suite of decision-making tools at https://www...

Expressing sand quantities as a depth makes communication easier. But to know the depth, you need to know how much sand was applied to begin with. I've been surprised at how many turf managers don't know the exact amount applied. This short episode explains why I think you should measure sand amounts.

I explain how I answered a couple questions about how much N and how much sand a particular grass might require. Specifically, I recommend adjusting N based on #ClipVol and sand based on #OM246.

Blog post discussed: https://www.asianturfgrass.com/post/sand-nitrogen-measuring-guessing/
OM246 calculator: https://asianturfgrass.shinyapps.io/om246/

Read more about all kinds of turfgrass topics at https://www.asianturfgrass.com/
Find a suite of decision-making tools at https://www.paceturf.org/
Get free ATC newsletters at https://www.asianturfgrass.com/newsletter/

The New York Golf Economic & Environmental Impact Report has interesting results for MLSN and ClipVol usage in New York. 58% of golf courses measure clipping volume and 47% interpret soil tests using MLSN.

Blog post: https://www.asianturfgrass.com/post/survey-says-mlsn-clipping-volume-golf-courses-new-york/
Full report: https://www.newyorkgolfimpact.org/

Read more about all kinds of turfgrass topics at https://www.asianturfgrass.com/
Find a suite of decision-making tools at https://www.paceturf.org/
Get free ATC newsletters at https://www.asianturfgrass.com/newsletter/

Piper and Oakley wrote that "there is nothing mysteriously beneficial in their formulas" and that mixed fertilizers are "extensively advertised" but "are not to be recommended." Arthur wrote that soil testing is a "commercial gimmick" and that fine turf with clippings collected needs only "a little nitrogen in spring, no phosphates, and very little potash."  I recommend an article I wrote that attempts to explain this in the context of #MLSN.

Blog posts discussed are:

- https://www.asianturfgrass.com/post/very-generally-used-not-to-be-recommended/
- https://www.asianturfgrass.com/post/jim-arthur-mlsn-and-precision-fertilization/

I explain why I recommend collecting soil nutrient samples to a 10 cm (4 inch depth). I also discuss the importance of repeated soil sampling in order to check the change in test results over time. I look at a photo gallery from the 2025 Danish Golf Championship.

Posts discussed include:

PACE Turf post about Vixen 7x stand loupes: https://www.paceturf.org/memberedition/where-to-find-small-magnifying-loupes

My Short Grammar of Greenkeeping book is one of the required books for turf class at Horry-Georgetown Technical College in South Carolina. Professor Jim Huntoon joined me to discuss the book, why he uses it for teaching, and how the internship (or summer cooperative work experience) program works.

Janne Lehto from Hirsala Golf in Finland attended the 15th International Turfgrass Research Conference (ITRC) in Japan. We discussed the heat and humidity in Japan during summer, saunas, his golfing experiences in Japan, and the ITRC.

The blog post with information about heat and humidity is: https://www.asianturfgrass.com/post/japan-hot-humid-latitude/
Read more about all kinds of turfgrass topics at https://www.asianturfgrass.com/
Find a suite of decision-making tools at https://www.paceturf.org/
Get free ATC newsletters at https://www.asianturfgrass.com/newsletter/

John Forrest and Jeff Austen joined me from Western Australia to discuss layers in the rootzone, the educational system and apprenticeships, and sand.

How do you compare sands to show to what degree one is finer or coarser than another? I've been trying to figure out an easy way to visualize this with comparison to reference materials. Adam Moeller joined me to discuss sands, Ksat, the coefficient of uniformity, particle sizes, and more.

John Emerson is an extension agent for the University of Delaware who has completed a statewide soil sampling project from good performing turf across the state. We talked about this project, and about nutrient management of turfgrass more generally, in this episode.

The D50 is a value that represents the median particle diameter in a sand. I calculated the D50 for 302 sands from around the world, and 15% of them are finer than the limit defined by the USGA Recommendations for a Method of Putting Green Construction.

Read about this at https://www.asianturfgrass.com/post/d50-median-sand-diameter/

I explain that moving from full sun to tree shade reduced photosynthetically active radiation by about 80%. I show an app, and a PACE Turf document, that will allow you to find both PPFD and DLI no matter where you are located.

I discussed these links:
- https://www.asianturfgrass.com/post/shade-and-sun/
- https://asianturfgrass.shinyapps.io/ppfd_by_time/
- https://www.paceturf.org/memberedition/weather
- https://www.paceturf.org/gallery/detail/photosynthetically-active-radiation
- https://www.asianturfgrass.com/post/rule-of-thumb-for-cloud-effect-on-par/

Read more about all kinds of turfgrass topics...

John Petrovsky is manager of USGA Green Section Education. He is also the host of the USGA Green Section podcast. We discussed a recent episode about GvX that had an especially insightful quote from Chris Tritabaugh. Also, the U.S. Open, championship golf, clipping volume, and even a bit about MLSN.

Links for topics we discussed include: