April 6, 2020

How Cutting Height Effects Top-Growth
Dr. Thomas A. Nikolai & Dr. Kevin Frank

Essential maintenance for a golf course could be defined as anything normally performed on a regular basis that maintains long term turfgrass health. If we didn’t consider it essential maintenance, then it is unlikely it would be performed as it would simply cost money without any significant value in improving turf quality or performance.  

Putting Green Height of Cut Study

Over the years there have been several height-of-cut (HOC) studies performed at Michigan State University.  In 2013 we initiated a bentgrass putting green HOC study. Clipping weights are presented in Table 1. There were 3 HOC in the study and the results showed the lowest HOC always had  the highest clipping weight (i.e. the lower the cutting height the more top-growth). The differences in clipping weights were especially greater in May than the summer months. If you can only mow your putting greens 3-4 times per week raising the HOC should reduce top-growth and reduce the likelihood of scalping resulting from reduced mowing frequency. 

 Table 1. 2013 Putting Green height of cut (HOC) study. Clippings weights in grams.

Lawn or Golf Course Rough Height of Cut Study

In 2019 a lawn care or golf course rough HOC study was initiated on a Kentucky bluegrass, perennial ryegrass, and fine leaf fescue mixture. HOC was 2, 2.5, and 3-inches. Clipping weights  are presented in Table 2. Once again, the lowest HOC always produced the highest clipping weight.  

Take Home Summary

These two studies show that raising mowing heights whether it’s for putting greens or higher cut turf such as lawns or golf course roughs will result in less top-growth between mowing. 

Photo 1. Height of cut study funded by the MTF in 2019, will continue in 2020 and 2021.

Table 2. 2019 Lawn mixture height of cut (HOC) study results from 2019.  Clipping weights in grams.

As a reminder Dr. Kevin Frank will be hosting a webinar, Tuesday at 1pm.  Click the banner below for information.

Reduced maintenance on athletic fields and lawns due to novel coronavirus

Turfgrass management considerations for athletic fields and home lawns during the “Stay Home, Stay Safe” executive order.

Kevin Frank, Michigan State University Extension, Department of Plant, Soil and Microbial Sciences - March 30, 2020

At Governor Whitmer’s news conference on March 26, 2020, she stated that landscape services are not included as a business necessary to sustain or protect life. I’m honestly not sure if athletic field maintenance also falls under this prevue, but my best guess would be that it does. Proceeding under the premise that both athletic field and lawn care maintenance are to cease through the April 13 “Stay Home, Stay Safe” executive order, the following is important to consider when maintenance does resume.

Although it’s been an early spring to this point, Mother Nature is still somewhat on our side. My only turf observations now are limited to my lawn, lawns on my daily walk and pictures on social media. At least in mid-Michigan, lawns and athletic fields have not required mowing yet. My expectation would be that although top-growth will certainly begin to accelerate, growth will not spiral out of control in the next couple weeks. When mowing does resume, consideration may need to be given to mowing at a higher than standard mowing height and slowly decreasing it over time to prevent any scalping injury that would set the turf back. Obviously, homeowners may still mow their lawns, so these comments are directed at professional management of lawns and athletic fields.

Many might have questions about crabgrass preemergence herbicide applications at this time. Using GDD Tracker, most mid- to southern portions Michigan are quickly approaching the optimum application window for preventative herbicides. The optimum application window stretches from 250 to 500 growing degree days (GDD) using a base 32 temperature. East Lansing, Michigan, for example has accumulated 190 GDD through March 26 and is forecast to reach the optimum application window on March 30. Although we’ll hit the optimum application window next week, it’s likely we’ll stay there for at least two weeks if not longer.

Even if we’re outside of the optimum timing when business resumes, you still have options. Herbicides that contain the active ingredient dithiopyr (Dimension) are effective up to the two-leaf stage of crabgrass, which even this year probably wouldn’t occur until early May. I discussed this issue with Dave Gardner from the Ohio State University. He indicated that in the numerous trials he’s conducted over the years, as long as crabgrass is not visible in the stand, all the typical preemergence herbicides are still generally effective and possibly a better option than relying solely on postemergence control.

For athletic fields that may not typically apply a preemergence herbicide due to spring seeding, keep in mind the herbicides Mesotrione (Tenacity) and topramezone (Pylex) can be good choices in certain situations. Both of these products can be applied on the same day of seeding Kentucky bluegrass for crabgrass control during establishment, but be careful and read the label about applications on other cool-season turf species.

We are all clearly in unprecedented times as this is the time of year when turf management is usually busy with activity preparing turf for the coming season. Stay safe, we’ll get through this and I’m confident we’ll be able to get the turf back in top condition sooner rather than later.  

This article was published by Michigan State University Extension. For more information, visit https://extension.msu.edu. To have a digest of information delivered straight to your email inbox, visit https://extension.msu.edu/newsletters. To contact an expert in your area, visit https://extension.msu.edu/experts, or call 888-MSUE4MI (888-678-3464).

2020 Michigan Turfgrass
Conference Guide - 90th Anniversary

The Michigan Turfgrass Foundation is proud to present the Conference Guide for this year's Michigan Turfgrass Conference.  Please click the photo above to read about this years event.  Early Registration for the Conference ends on December 27th, so Sign Up today!