A look into the profile of one of the greens at Heritage Oaks Golf Course in Harrisonburg, Va., after a PlanetAir application. Notice the curved arc of the tine hole and the slicing effect through the thatch layer. Photos by Charlie Fultz
Thatch issues and high organic matter (OM) on bentgrass greens tend to lead to many issues year-round in the transition zone, but also in all areas where bentgrass is the chosen grass for greens. Too much thatch and OM can cause watering issues and can
lead to localized dry spot, disease, inefficient nutrient use and availability, and many other issues during the hot summers in Virginia. The transition zone is a difficult enough place to maintain turf without the problems listed above.
Being able to manage thatch and get OM to acceptable levels are two important management issues I had to address at Heritage Oaks Golf Course in Harrisonburg, Va., since I inherited problems with both. But some research over the winter, broad soil testing,
work with a respected turf lab and a commitment to a “program” have helped turn my greens into much healthier and more manageable surfaces.
I became the golf course superintendent at Heritage Oaks GC in May 2020. It was right in the middle of a course closure, as the city decided to close all recreational outlets due to COVID-19. I had not been a superintendent in 13 years; I had left the
industry and ran my own athletic-field-management company for the six years prior and spent time as a technical representative for a foliar fertilizer company. While I didn’t like having the course closed, it allowed me time to get to know the
greens at Heritage Oaks, and I found we had some issues.
There was a substantial thatch issue on the greens — over 1 inch of a thick fibrous mat — and the collars had been sodded four to five times over the years. Layering had shown up in the profile. The greens at Heritage Oaks are built to USGA
recommendations. Constructed in 2000-2001, they didn’t percolate well. Customers had long complained how the greens at Heritage were soft, slow and spongy (the three S’s you don’t want). I was determined to address these issues with
the standards I’d practiced since coming into the business: twice-a-year aerification, using ½-inch coring tines; topdressing to fill the holes; and spiking greens regularly during the summer.
The No. 4 green at Heritage Oaks mid-summer. No nitrogen was applied throughout the growing season, and consistent, healthy greens were present the entire year through a prolonged summer and fall drought.
The issue we encountered with this approach the first two years was almost uncontrollable growth after such events (including the monthly spiking). We applied growth regulators weekly, but we could not get the greens growth to slow down. We started backing
off on the rates on the greens without any luck. I was applying 0.10 pounds nitrogen per 1,000 square feet every other week, and I began easing off that rate to where I was putting down 0.10 pounds nitrogen per 1,000 square feet just once a month.
But that was not stopping the uncontrollable growth we saw, especially in 2022.
I was at wit’s end, because we continued removing an unacceptable amount of clippings off the greens, and our green speeds suffered. Our rooting toward the end of the summer of 2022 was, on several of the greens, barely 1 inch by the end of August.
I was concerned about even aerifying in August 2023 because I wasn’t sure the greens would take it. 2022 left me with many questions and not a lot of answers.
I was more determined than ever to find a way to make my greens better. During the winter of 2022-2023, I began reading how some superintendents had begun putting almost no nitrogen on their greens in-season. I read how they were using soil and tissue
tests to determine what their greens needed and when. I also read how many superintendents were bucking the trend of twice-a-year coring and heavily topdressing their greens. I also spoke to several notable soils professionals in the industry and
began to zero in on what I perceived was the solution to my problems.
2023 was going to be the year of no nitrogen for me. It became my Twitter (now X) hashtag: #NoNin2023. With everything I’d read and studied over the winter, I formulated the following program:
Twice-a-year heavy verticutting with ¼-inch solid quad tine aerification and topdressing to fill in the vertical mowing grooves.
Monthly slicing of the greens with the PlanetAir.
A spray program consisting of:
a. Weekly: trinexapac-ethyl at 6 ounces per acre and prohexadione calcium at 4 ounces per acre.
b. Every two weeks:
- Soluble calcium (10%) application.
- Minors package.
- Soluble potassium with seaweed extract.
- Fungicide application.
c. Once a month:
- Biostimulant application (with wetting agent).
Blackstrap molasses application (with wetting agent).
Rolling greens a minimum of two times a week in lieu of mowing.
Annual ½-inch solid deep tine aerification (minimum 7 inches deep).
Prior to program implementation, we did an in-depth soil, nutrient and OM analysis through an accredited soil laboratory out of Pennsylvania (Tournament Turf Labs) in February 2023. I found my baselines and saw that my greens needed a little bit of phosphorus
and potassium (which always seems to be the case in sand-based greens), as well as calcium and sulfur. With all this data in mind, the program began March 2023.
The author’s PlanetAir machine. The tines pictured are the larger 1⁄4-inch slicing tines and are used only in the spring and fall, with the course utilizing 1⁄8-inch slicing tines through the summer months.
Throughout the entire process, one thing that stood out was how well the greens held their root depth and consistent speeds. As is the case in the transition zone, root depth will shallow during the heat and humidity of a Virginia summer, but we held
root depth substantially better in 2023 than in the previous two years. We dealt with a substantial drought throughout most of the summer in Virginia, and the greens performed beautifully.
We didn’t see any thinning of the Poa annua on our greens (we are about 80% bentgrass, 20% Poa), and our greens held up well with the 20% increased play we had received in 2023 over 2022. We were able to maintain green speeds much better, and whenever
we thought we might need a little punch of nitrogen, we instead sliced our greens with the PlanetAir. Almost immediately, we saw the green-up, and we did that monthly.
Green speeds became more controllable. We spent the entire summer mowing at 0.110 inch and maintained green speeds of 10.5 on the Stimpmeter. There were a few times in the spring we hovered around 11-12 (we were dry and windy in the spring), but with
our play I was happy with 10.5
The biggest question I had from this program was to see if our OM showed a decrease in the upper 1.5 inch. I chose three greens on the course to test: No. 2, which is wide open; No. 13, which is partially shaded; and No. 16, which is our largest and dries
out faster than any of the others. We pulled soil samples in February 2023 and had them analyzed. After the season, in October, I pulled soil samples for testing and sent them away to be analyzed.
We found decreases of 25%, 29% and 37% from February to October 2023 in the amount of OM in the top 1.5 inches of the three greens tested. Two of the three greens now had OM in the acceptable range, and the third (No. 16) is very close. All of this was
achieved with no hollow-tine core aerification, minimal topdressing and a modest golf course budget.
It was even better than what I thought was possible.
I am blown away by what I saw in the results. Several of the superintendents I had talked to said it took a good two growing seasons to achieve the results they wanted, and then they began to add nitrogen incrementally back into their programs. That is
the plan I also will use going into the 2024 season. I do not plan to apply any N outside of a small amount this month with our vertical mowing. I do not plan to solid-tine the greens at all in 2024 outside of the PlanetAir use, and we now plan to
go every three weeks instead of monthly. The response to the machine is noticeable, and you can tell when the greens “want” to be opened again. I do not plan to change the spray program for 2024, as I am happy with the results achieved
this year.
The slicing results after using the PlanetAir machine.
With all of that in mind, #NoNin2023 will now be #NoNin2024, and I hope to reach the goal of all of my greens finding OM acceptable levels by the end of this year.
Once we reach acceptable levels across the spectrum for all our greens, I will begin to add N back in the form of soluble or foliar applications and maintain the greens as such. I will also watch the OM numbers in the future, because I also do not plan
to core-aerify the greens if it isn’t needed. I believe strongly that our thatch and OM levels can be maintained and controlled using the methods we implemented in 2023.
Charlie Fultz, general manager and GCSAA Class A golf course superintendent at Heritage Oaks Golf Course in Harrisonburg, Va., is an 18-year member of GCSAA. He won the association’s Leo Feser Award — presented to the best superintendent-written article in GCM — in 2006.