Arrowhead Stadium, home of the Kansas City Chiefs, uses natural grass rather than artificial turf. It has maintained a natural playing surface since the stadium opened in 1972, making it one of the NFL venues that has never switched to synthetic. The choice is not purely traditional, though. Kansas City sits in what turf professionals call the transition zone, a climate band where keeping a living field healthy year-round requires serious effort and creative agronomy.
What Grows on the Field
The playing surface at Arrowhead is built on a sand-based root zone with an extensive drainage and irrigation system underneath. The primary grass species used on the field is a warm-season turfgrass suited to summer heat. Bermudagrass and its hybrid varieties are standard choices for athletic fields in the region because they tolerate heavy foot traffic, recover quickly from damage, and thrive in the hot Missouri summers. But bermudagrass goes dormant in cold weather, turning brown and essentially sleeping through the winter months. That creates an obvious problem for a football team whose season stretches from September into January or beyond.
To keep the field green and functional during colder months, grounds crews typically overseed dormant bermudagrass with a cool-season turfgrass. Perennial ryegrass is the most widely used species for this purpose because it germinates quickly and provides a green, actively growing surface through fall and early spring.1International Turfgrass Society Research Journal. Alternative cool‐season turfgrass species for overseeding dormant bermudagrass The result is a two-species system: the bermudagrass carries the field through summer, the overseeded ryegrass takes over for winter, and the transition between them has to be managed carefully so neither chokes the other out.
Why Kansas City’s Climate Makes Things Harder
Kansas City sits squarely in the transition zone, a geographic band running roughly through the middle of the United States where neither warm-season nor cool-season grasses are perfectly at home. Winters get cold enough that bermudagrass can suffer real damage from freezing, and the risk of turf loss from severe cold is a well-documented concern for grounds managers in this climate.2PubMed Central. Optimization of Nitrogen, Phosphorus, and Potassium Fertilization Rates for Overseeded Perennial Ryegrass Turf on Dormant Bermudagrass in a Transitional Climate A particularly brutal cold snap can kill bermudagrass outright, forcing an expensive and time-consuming re-establishment of the entire root system.
To fight this, Arrowhead Stadium’s field relies on an underground heating system embedded beneath the playing surface. Heated water circulates through pipes below the root zone, keeping soil temperatures high enough to prevent the grass crowns from freezing during the coldest weeks. This kind of subsurface heating is standard for natural-grass NFL fields in cold-weather cities but adds significantly to operating costs. The stadium also uses grow lights and tarps at various points during the year to supplement natural sunlight, particularly when the stadium’s structure casts shadows over parts of the field. Shade stress is a known challenge for turfgrass in enclosed or partially enclosed stadiums, and Arrowhead’s open-air design gives it an advantage over domed or roofed venues in that regard.
The NFL’s Shift Away From Artificial Turf
Arrowhead’s commitment to natural grass has gone from a somewhat old-fashioned choice to an increasingly mainstream one across the league. In the early 2000s, a large share of NFL stadiums used some form of synthetic turf, often marketed as lower-maintenance and more weather-resistant than natural grass. But player advocacy, injury research, and pressure from the NFL Players Association have steadily pushed the league toward natural surfaces. As of recent seasons, the majority of NFL teams now play on natural grass, and several teams that had used artificial turf for years have made the switch back.
The reasons behind this shift center mostly on player health. Research comparing injury rates between the two surfaces consistently points in the same direction, even if the size of the difference varies by study and by body part.
Injury Rates on Grass Versus Artificial Turf
A study examining all lower-extremity injuries across the 2021 and 2022 NFL seasons found that the injury rate on natural grass was about 1.22 injuries per game, compared with about 1.42 on artificial turf. More strikingly, the odds of an injury requiring season-ending surgery were roughly 60 percent higher on artificial turf than on grass, and that gap held even after accounting for weather, player age, position, week of injury, and prior injury history.3PubMed Central. Lower Extremity Injury Rates on Artificial Turf Versus Natural Grass Surfaces in the National Football League During the 2021 and 2022 Seasons
A broader systematic review of the published literature on lower-extremity injuries across sports found that foot and ankle injuries are consistently more common on artificial turf, whether old or new-generation synthetic surfaces. The picture for knee injuries is somewhat murkier overall, though elite-level football athletes may face higher knee injury risk on turf compared with grass.4PubMed. Lower Extremity Injury Rates on Artificial Turf Versus Natural Grass Playing Surfaces: A Systematic Review The concern about ACL tears in particular has driven much of the conversation. Biomechanical testing shows that artificial turf generates higher rotational forces and greater cleat-surface traction than natural grass, and that combination may increase ACL injury risk.5DigitalCommons@PCOM. The Impact of Artificial Turf versus Natural Grass on Anterior Cruciate Ligament Injury Rates in Football and Soccer: A Scoping Review
The mechanism is fairly intuitive. When a player plants a foot and pivots, the shoe needs to release from the surface at a certain point. If the surface grips too hard, the knee absorbs forces it was not designed for. Mechanical testing confirms that artificial grass surfaces show higher peak torque, rotational traction, and stiffness compared with natural grass.6PubMed Central. Influence of Cleats-Surface Interaction on the Performance and Risk of Injury in Soccer: A Systematic Review Natural grass gives a little more, both literally and figuratively. The soil and root system beneath living grass provides a degree of give that synthetic infill over a hard base does not replicate as well, even in the latest-generation products.
This body of evidence is a big reason why the NFL and the Players Association have pushed so hard for the remaining artificial-turf venues to make the switch. For venues like Arrowhead that never left natural grass, the research has essentially validated a choice that was already in place.
How Surface Type Affects Heat
Injury risk is the most talked-about difference between grass and turf, but surface temperature may be the most dramatic. For early-season games in Kansas City, when September and early October can still bring summer heat, the type of surface underfoot matters a lot for player comfort and safety.
A systematic review of thermal measurements across multiple sports fields found that third-generation synthetic grass surfaces averaged roughly 46°C (about 115°F), while natural grass averaged around 24°C (about 75°F) in comparable conditions. Even synthetic surfaces with cooling technology built in still averaged around 40°C, well above natural grass.7PubMed Central. The effect of synthetic grass sports surfaces on the thermal environment: A systematic review That is a difference you can feel through your shoes and one that affects how quickly players overheat during play.
A field study comparing artificial turf directly with natural turf found that the daytime mean surface temperature of artificial turf reached about 50°C (122°F), compared with around 30–32°C (86–90°F) for natural turf. At its peak, the artificial surface hit about 72°C (162°F), which is hot enough to cause irreversible skin burns in as little as 15 seconds of contact.8Building and Environment. The microclimate, surface energy flux and human skin burn risks of artificial turf as compared to natural turf A separate measurement study recorded maximum surface temperatures on artificial turf reaching the same 72°C mark, significantly hotter than natural grass, bare soil, or even asphalt measured in the same conditions.9WSEAS TRANSACTIONS ON ENVIRONMENT AND DEVELOPMENT. Surface Temperature Experienced and Irrigation Effects on Artificial Turf
The reason for the gap is straightforward. Living grass cools itself through transpiration, the same process that makes standing in a park feel cooler than standing on a parking lot. Water moves through the plant and evaporates from leaf surfaces, pulling heat out of the immediate environment. Synthetic fibers do not transpire. They absorb solar radiation and re-radiate it as heat, behaving more like pavement than vegetation. Irrigating artificial turf can bring temperatures down temporarily, but the effect fades fast once the water evaporates from the synthetic material.
For an outdoor stadium like Arrowhead that hosts games in late summer heat, this thermal advantage of natural grass is not trivial. Players spend hours on the surface during warm-ups and games. Ground-level temperatures can be substantially higher than the air temperature announced on the broadcast, and a 20- to 30-degree-Celsius gap between surface types translates into meaningfully different heat exposure for athletes.
Maintaining a Natural Field Through a Full Calendar
One of the traditional arguments in favor of artificial turf is that it can handle constant use without rest. A natural grass field needs recovery time after being torn up by cleats, and heavy events like concerts can destroy sections of turf entirely. Arrowhead hosts not only Chiefs games but also concerts, soccer matches, and other events throughout the year. Every non-football event that rolls heavy staging equipment across the field or packs fans onto the grass creates potential damage that the grounds crew has to repair before the next game.
NFL grounds crews have become increasingly sophisticated at managing this. Portable sod is one tool, where pre-grown sections of grass on reinforced mats can be laid down to replace damaged areas in a matter of days. Some stadiums use modular tray systems that allow entire panels of turf to be swapped out. Growing technology like supplemental lighting rigs, which look like massive banks of grow lamps on wheels, can be rolled onto the field between events to accelerate regrowth. At Arrowhead, the open-air design helps because natural sunlight reaches most of the field surface for a good portion of the day. Stadiums with large overhangs or retractable roofs often struggle more with shade-related turf health.
The overseeding cycle is another layer of complexity. As fall approaches and bermudagrass begins to slow down, the crew seeds ryegrass into the existing turf. The timing has to be precise: too early, and the ryegrass competes with still-active bermudagrass; too late, and it does not establish before cold weather arrives. Then in spring, the reverse transition happens. The ryegrass needs to step aside as bermudagrass wakes up and resumes growth. Grounds managers use mowing height, fertilization, and sometimes herbicides to manage which species dominates at each point in the calendar. It is a year-round job with remarkably little margin for error, especially when playoff games extend the season into January or February.
What Players and Fans Actually Notice
From the stands or on television, the distinction between a well-maintained artificial surface and a healthy natural grass field can be surprisingly hard to spot. Modern synthetic turf is designed to look like real grass, complete with varying shades of green fibers and organic-looking infill. But players describe the feel as noticeably different. Natural grass is softer underfoot, especially when the soil beneath it has some moisture. The surface has a slight inconsistency that synthetic fields lack, with some spots firmer than others depending on how compacted the soil is or how recently the field was aerated. Paradoxically, players tend to prefer that slight unpredictability because it more closely mimics the surfaces human legs evolved to run on.
The cleat interaction is another difference players emphasize. On natural grass, a cleat digs into the soil and releases relatively easily when the foot rotates or lifts. On synthetic turf, the fibers and rubber infill grip the cleat differently, and as the biomechanical research shows, that grip tends to be stronger and less forgiving during cutting and pivoting movements. Some players change their cleat type depending on the surface, opting for shorter studs or different configurations on turf to reduce the rotational traction that can stress joints.
Kansas City’s weather adds another layer to the game-day experience. Late-season home games at Arrowhead can feature frozen or snow-covered grass, which changes the playing surface dramatically. A frozen natural field is hard and slick, reducing traction but also reducing the rotational forces that cause non-contact injuries. A snow-covered field slows the game down and turns footing into a contest of balance. These conditions are part of Arrowhead’s identity as a cold-weather venue and would be fundamentally different on an artificial surface, which handles cold and precipitation in its own ways but does not freeze or become snow-covered in quite the same organic fashion.
Why Some Venues Still Use Artificial Turf
If natural grass is better for players and cooler in the heat, the obvious question is why any NFL stadium still uses synthetic surfaces. The answer usually comes down to architecture and economics. Fully enclosed domed stadiums struggle to grow real grass because the roof blocks sunlight and restricts airflow. Retractable-roof venues have an easier time but still face challenges with shade patterns and humidity control. Multi-use facilities that host dozens of events per year also feel the pull of synthetic surfaces, since artificial turf can tolerate far more foot traffic without visible damage.
Cost plays a role too, though the math is more complicated than it first appears. Artificial turf has a high installation cost but relatively low day-to-day maintenance expenses. Natural grass fields require year-round staff, irrigation systems, fertilization programs, mowing, aeration, overseeding, heating, and supplemental lighting, all of which add up. But artificial turf has its own hidden costs: the surface has to be replaced every eight to ten years, infill needs replenishment, and deep cleaning is necessary to manage bacteria and odor that build up over time. When injury costs are factored in, with players missing games and undergoing surgeries at higher rates on synthetic surfaces, the economic picture shifts further in favor of natural grass for organizations that can support it.
For Arrowhead Stadium, the open-air design, the availability of sunlight, and the organizational willingness to invest in a full-time grounds crew have made natural grass a sustainable choice for more than fifty years. The trend across the league suggests that more teams are reaching the same conclusion, not out of nostalgia, but because the data on player health has become difficult to ignore.