The USGA announced it has revised its recommendations for putting green construction, and has included emphasis on greater communication and collaborations, the consideration of new technology and materials, and added clarity to certain agronomic verbiage.
The USGA’s basic 1960 guidelines haven’t changed much over the years, says USGA Agronomist Brad Whitlark, with the last revision issued in 2004. Whitlark addressed a crowd of superintendents Monday during an education session focused on turf solutions where he outlined many of the changes.
The USGA approached revising its putting green recommendations with four main objectives in mind:
- To review new technology and how it impacts or improves green construction.
- Provide education by improving the clarity and increase the awareness of the USGA’s principles and methodology.
- To maintain a broad range of methodology.
- Consider alternative methods by recognizing the potential benefits and pitfalls of other methods of green construction and to provide guidance for those methods.
The process involved extensive industry cooperation with the USGA reaching out to various scientists, golf course architects, superintendents and agronomists for their input. The USGA then contracted with turf consultant Dr. Norm Hummel to write the revisions.
The revisions were included in a variety of steps the USGA suggests superintendents follow for success when engaging in green construction. Some of those include:
- Assemble a Team. The revision advises to bring together the various parties who will be involved in the design, construction and maintenance of the new green. In addition, at this time it’s advised to look at the putting green cavity and subgrade, as well as re-examine the green drainage including the addition of clean out ports and a perimeter drain that extends into low-lying areas.
- Gravel & Intermediate Layer. Wicking barriers are now optional. It advises to no longer use sulfate soundness test or LA abrasion test, instead conduct a “micro-deval test” for material stability. In addition, the USGA acknowledges iron oxide layers may form when using an acidic root zone over neutral or alkaline gravel.
- Root Zone Mix. The revision includes a better explanation of root zone materials and provides better guidance on choosing root zone mixtures for site conditions. It addresses the use of organic matter and provides a warning about material variability. It expands and enhances the discussion on water and nutrient retention with an emphasis on moisture retention while retaining air porosity. It also expands the discussion on the do’s and don’ts of root zone blending.
- Top Covering, Placement, and Smoothing. Mentions power tamping as a method to firm the perimeter of greens to minimize settling.
- Pre-Plant Prep. Offers to consider seed, sod and sprig options. Mix pre-plant fertilizer to the top 2 inches of soil depending on soil chemistry.
- Grow In. Advises to reach out to local agronomists and soil testing laboratories to develop a grow-in plan.
Whitlark says the USGA does not expect to issue any additional updates, rather it considers the 2018 version to be a document that will grow and evolve.
“We’d like to now treat this as a living and breathing document and update it as need and as we see fit,” he says.