A machine called a Renovator is equipped with steel shanks that pulverize sod into sprigs and can cut sprigs into compacted soil on 6-inch centers. Discs and a roller push the sprigs into the soil 1.5 inches deep. This machine has been used extensively in southern Arizona and southern Nevada where compacted, poor soils are common.
Rolling fairways with a 2-6 ton asphalt roller is commonly done to push sprigs into the ground, along with producing a smoother, firmer playing surface. A smooth surface will yield better mowing quality. In some instances, courses that tilled the fairways prior to planting have seen mower scalping after turf establishment because the ground was not smooth. Once the turf is established, it will take years of topdressing to effectively smooth out any imperfections, so it’s very important to plant into a smooth surface.
Recommended sprig rate
Sprig rates for fairway renovation are higher than for new construction or sprigging into soil with no competition from remnant grasses. A sprig rate of 400 to 800 U.S. bushels per acre is common. A U.S. standard bushel has a volume of 1.25 cubic feet, a Georgia bushel is supposed to be 0.4 cubic feet and a Texas bushel may range from 0.4 to 1.23 cubic feet. While a higher sprig rate is more expensive, it expedites establishment and helps the new turf outpace regrowth of any remnant grasses. At higher sprig rates, full turf cover may be accomplished in about eight weeks from planting.
Ideal time to plant sprigs
This may seem counterintuitive, but it is not recommended to plant sprigs when it is hot and dry. Ideally, plant sprig material during hot and humid weather. Planting when hot and dry slows establishment and will require more inputs – especially water. Alternatively, research shows success planting dormant or near-dormant sprig material early in the year. A study completed in Arkansas in 2016 indicated dormant sprigging bermudagrass and zoysiagrass achieved full cover by the end of the season and performed just as well as summer sprigging with much less inputs. The authors stated that, “Dormant sprigging reached full coverage as fast or faster than traditional spring or summer planting dates at both locations, indicating that bermudagrass and zoysiagrass establishment can be achieved earlier in the growing season using dormant sprigging methods.”
Treat sprigs to aid establishment
Treating bermudagrass with fungicide prior to sprigging accelerates establishment. Coordinate with the sod supplier to apply a fungicide such as a combination product with fluxapyroxad and pyraclostrobin four to six weeks prior to cutting sprigs.
How long will it take for sprigs to establish?
Full turf coverage and playable conditions can be achieved six to 10 weeks after sprigging if the area is closed to allow for frequent irrigation and routine nitrogen inputs. In general, it is recommended to supply 0.25 to 0.5 pounds of nitrogen per 1,000 square feet per week for the first six weeks after planting.
Case Studies in Fairway Conversion
Many courses in California have converted to hybrid bermudagrass over the past 15 years and that trend continues in earnest due to rapidly rising water costs and imposed water limitations. Several examples of courses who have made the conversion are described below.
Birnam Wood Golf Club
Birnam Wood Golf Club in Santa Barbara historically maintained a mixed stand of cool-season turfgrasses, sometimes referred to as the “California Turf Surprise.” This turf composition produces acceptable playing conditions, but never delivers a premier golf experience and the water demand is higher than it would be for warm-season turf. Historically, Birnam Wood budgeted for about 185 acre-feet of water use annually (approximately 60 million gallons) with a cost of nearly $200,000 per year.
The golf course’s leadership recognized an opportunity to improve the consistency of playing conditions and reduce resource inputs, most notably irrigation water, by converting the cool-season turf to bermudagrass. In 2015 and 2016, the golf course converted 31 acres of fairway to ‘Santa Ana’ bermudagrass and converted the roughs to ‘Tifway 419’ bermudagrass. In addition, 7.2 acres of irrigated turf was replaced with low-water-use landscaping.
After the renovation, the golf course water budget is about 135 acre-feet annually, which is a 25% reduction in annual water inputs. The cost of water for the course has increased over 500% in the past decade and water costs today are nearly $11.00 per hundred cubic feet (HCF). At current prices, the 25% water reduction saves the facility over $100,000 annually. The conversion has also saved approximately $100,000 per year in fertilizer, seed and plant protectants. The cost of the project, which included minimal soil preparation and sodded bermudagrass, was about $1.25 million and within seven years the project paid for itself.
Menlo Country Club
Menlo Country Club in the San Francisco Bay Area converted the fairway on their sixth hole from perennial ryegrass to ‘Santa Ana’ bermudagrass in 2018 to see whether water savings and improved playability would justify converting all the fairways. Golf course superintendent Chris Eckstrom documented significant water savings on this fairway – noting that 25% savings over cool-season grasses is very realistic. Based on this success, in 2021 the golf course converted the remaining 33 acres of perennial ryegrass fairways to ‘Santa Ana’ bermudagrass and replaced 2.4 acres of turf with naturalized grasses.