Ben Wherley, Ph.D., and master's student Garrett Flores at Texas A&M AgriLife Research in College Station set out to answer a practical question: can the coffee grounds the world throws away actually help turf? With funding from the U.S. Golf Association Green Section, they ran two studies, and the results line up with what growers using our blends see in the field.
What the study measured
The team looked at coffee grounds two ways. The first was a two-year topdressing trial that compared fresh and composted grounds against seven other organic and synthetic fertilizers. The second worked spent grounds into the root zone at 10 and 20 percent by volume and tested them against sphagnum peat moss and sand on Tifway Bermuda grass.
What they found
- On their own, grounds did little. Spread on the surface by themselves, spent coffee grounds gave minimal benefit. Paired with other nutrient sources, though, they held those nutrients longer than synthetic fertilizer did.
- In the root zone, they matched or beat peat. After an early stretch of mild yellowing during establishment, turf grown in coffee-amended soil caught up within three months and equaled or exceeded the peat moss and sand controls for growth, color, density, and nutrient retention.
- They held up under drought. Coffee-amended plots resisted wilting longer than the other treatments and bounced back faster once they were watered again.
- The nitrogen is real. Coffee grounds carry 2.5 to 3 percent nitrogen, and a 13,000-square-foot putting surface built with them performed well after a year.
Why it matters for growers
The study points to coffee grounds as a credible, renewable stand-in for peat moss in golf and sports-field root zones, with better water resilience as a bonus. It is the science behind why coffee compost is the foundation of every Mayer blend, and why companies like Mayer Materials and GeoJava have built turf and lawn products around it.