Anatomy of a green restoration

When a golf facility takes on a greens restoration project like the one underway at Savannah Harbor, the term “USGA specs” frequently comes up. It’s a reference to the set of guidelines titled “Specifications for a Method of Putting Green Construction” that was first published by the U.S. Golf Association in 1960.

The USGA Green Section – the organization's arm that "develops and disseminates sustainable management practices that produce better playing conditions for better golf" – has tweaked the guidelines several times, typically to reflect advances in the science of agronomy or technological innovations. The document was last updated in 2018.

A golf course is built on a subgrade that’s sculpted to create various features of the playing area, including fairways, tee boxes and bunkers, as well as the shape and contours of the putting greens. The 130 acres of the golf course on Hutchinson Island is composed of dredge spoil from the Savannah River, capped by roughly a foot of sand.

On each green complex, drainage pipes that radiate outward from a center line are laid in trenches and covered with four inches of gravel. Above the gravel is 12 inches of “rootzone mix,” a combination of sand and organic matter as prescribed for the property’s climate and overall soil conditions. The rootzone is carpeted with grass designed specifically for golf greens; Savannah Harbor will be using a brand called TifEagle, which is the third generation of bermudagrass varieties developed by plant geneticists at the Coastal Plains Experiment Station in Tifton Ga.

“Eagle has proven itself to be the premier ultra-dwarf variety,” says Lynn Childress, Director of Grounds at Savannah Harbor, referring to grasses bred to withstand the stresses of low mowing heights, frequent verticutting (to control thatch build-up), as well as cold and heat tolerance, and resistance to disease.

Restoration of a golf green doesn’t necessarily entail rebuilding from the subsurface up. If the drainage layer is intact and functioning well, and the entire layer of greens mix hasn’t been compromised by disease or pests, only the top four inches needs to be removed and replaced before new grass is planted.

“The problem for a green when it gets older is not 10 inches down; it’s just in the top four inches,” says Childress. “That’s where all the living and dying happens with the root system. It turns into organic matter, and that doesn’t drain well. It doesn’t allow air to flow back and forth, and it harbors disease and weed infestation. That’s what we have to get rid of.”

As happens to all greens over time, Savannah Harbor’s have shrunk, and some of their subtle contours have disappeared. The putting surfaces will be restored to their original size, as designed by course architect Bob Cupp.

“These greens are huge,” says Childress, who has been Savannah Harbor’s course superintendent since it opened. “It’s part of who we are.”

The project also includes replacement of the irrigation loops around each green. “That will help with (water) coverage and make it easier for Lynn to grow quality grass,” says Ron Despain, Senior Vice President for Golf Development at Troon Golf, which built the course and has had the golf operations management contract since it opened.

Todd Godwin Construction, based in Ellabell, Ga., is the irrigation and turfgrass installation contractor. Childress used Godwin’s company when the club’s bunkers were renovated in 2014. “He does exceptional work,” says Childress, “and I asked for him specifically.”

Work began at holes No. 5 and 6 on April 11. Two weeks later, every green was in an early stage of refurbishment. (Work is slated to commence on the practice green on May 2.) Dustin Strickland, Troon’s South Carolina-based regional Director of Agronomy, will make weekly visits to monitor progress and provide consultation. Despain says he expects to conduct monthly inspections.

Here’s how the project will unfold:

• The first task on each green is to strip sod from the areas that will become the green collars, as well as the paths leading to each hole’s irrigation connection. The irrigation connection valves will be replaced, as will the sprinkler heads that surround each green. The process includes fusing new joints or pipe sections, and inspecting the irrigation wiring and replacing it when necessary.

• When irrigation installation has been completed on a hole, its putting surface will be stripped to a depth of four inches. The eight inches of soil left above the gravel drainage bed will be tilled, with a product called Profile added to the mix. “Profile is a porous ceramic material that actually replaces the peat that was typically used in older greens,” says Despain. “It has a better water holding capacity and a better nutrient holding capacity than peat.”

• Once the tilling is complete, a new four-inch layer of 90 percent sand, 10 percent Profile will be laid. (The piles of sand on the road between the 17th and 18th holes are pre-mixed rootzone material that’s been set aside for the new top layer on each green. At left is a closeup of the root zone mix.) The top layer then must be compacted and graded to ensure that the surface drains properly and to restore original contours.

• To achieve that end, Godwin’s shaping crew will work from green gradient diagrams – topographical surveys that show variations of one-tenth of an inch. “This enables the shapers to detect areas that are flat, which doesn’t allow for drainage,” says Childress. “The consulting agronomists (from Troon) want to put subtle movement back into the greens, which has the dual effect of improving drainage and making them a little more interesting.”

• After each green has been shaped, it gets an application of fertilizer designed specifically for planting preparation. Then the putting surfaces will be sprigged with TifEagle and the collars will be sodded with Tifway 419 Bermuda turfgrass (the same as the fairways). Childress hopes to start planting by the first week of June.

• Next comes grow-in, which includes weekly applications of fertilizer and lots of watering. After three weeks, the new grass should be hearty enough for mowing.

“At some point the course is going to look complete, but we have to repeat the process of grow and cut, grow and cut, grow and cut until the root system is strong enough to withstand the stress of play,” says Childress.

Once the greens have matured, the goal will be to mow as often as possible, which Childress believes separates championship caliber courses from the also-rans. If the weather cooperates and no glitches impede progress, Savannah Harbor should be ready for play by late August.

“I’ve been asked to make sure the place looks new when we open up,” says Childress. “And it will.”