I have received a lot of questions about the U.S. Open at Pinehurst No. 2 over the past month. As the first U.S. Open played on ultradwarf greens, people who manage similar surfaces naturally want to know if we learned anything that can improve their programs. I want to share a few takeaways on ultradwarf management from my travels this month and from this year’s U.S. Open that may be helpful.
- Double cutting is a great hack for surface management. Rolling and other practices have their place, but the more you can mow during the growing season, the better. If you really want to make a difference, incorporate a few evening or dry mows as well. Backtrack mowing (up and down the same pass) is key to interacting with the putting surface in multiple directions and managing grain. If you can double cut daily in the growing season, I would recommend it.
- Wise use of plant growth regulators (PGRs) is important for successful ultradwarf management in the warmer months. Starting with modest rates at the beginning of the growing season and increasing as heat and humidity increase is a key for success. I have written quite the opposite advice about managing bentgrass greens. Superintendents often see poor quality of cut on ultradwarf greens in July and August, and PGRs can help address that issue along with other cultural practices. Combining Primo Maxx (trinexapac-ethyl) with Anuew (prohexadione calcium) on ultradwarf greens has proven successful; however, optimal rates and application intervals vary greatly from course to course so test new combinations on a practice or nursery green before applying on all your greens.
- There’s no substitute for sand topdressing and light vertical mowing in the growing season. Removing small amounts of leaf tissue and replacing with sand is a fundamental part of ultradwarf surface management. Ball roll is improved and scalping is reduced with these practices. As with mowing, backtrack vertical mowing is a great way to manage grain in ultradwarf greens. Vertical mowing down grain is the most aggressive direction, so if too much disruption occurs, try making your first pass in a different direction. Mixing in another light vertical mowing later in the week without sand won’t hurt either. Do not use carbide tips on putting greens unless you are trying to aggressively remove material. Light, frequent vertical mowing is very different than vertical mowing or deep, linear aeration.
- Measure what matters. Collecting putting green data and focusing on consistent surface performance has been a key for Pinehurst No. 2. Whether it be for daily play or the U.S. Open, objective data supports management decisions and bolsters communication. Managing appropriate green speeds also improves the golfer experience and pace of play on exciting architecture like Course No. 2. The USGA’s DEACON® and GS3™ tools are used for daily data collection and analysis at Pinehurst and were used during the U.S. Open as well. Whether you are challenging the best in the world or the golfers at your course, these metrics can improve your operation.
While much has been written about ultradwarf putting green management in the past, I highly recommend the following articles for a deeper dive:
- The Ins and Outs of Managing Ultradwarf Putting Greens
- Highlights From the 2018 USGA Ultradwarf Surface Management Workshop
Southeast Region Agronomists:
Jordan Booth, Ph.D., senior director, USGA Course Consulting Service – jbooth@usga.org
Chris Hartwiger, director, Agronomy – chartwiger@usga.org
Chris Neff, agronomist – cneff@usga.org