SANTA CLARA, Calif. — During his drive to work Tuesday, San Francisco 49ers head groundskeeper Matt Greiner called up his good friend and Kansas City Chiefs counterpart Travis Hogan.
The message: Bravo!
Arrowhead Stadium had just hosted a game with a minus-30-degree wind chill — a massive storyline heading into the contest — but the field and footing were nonfactors.
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“It didn’t look like Augusta National — far from it,” Greiner said this week. “But to have the footing the way it was with those conditions and those temperatures? It was a marvel.”
Now Greiner and his crew are preparing for their own winter weather, showers that are expected to turn to light rain right around Saturday’s 5:15 p.m. PT kickoff. Greiner admitted he nervously checked the forecast every two hours during the run-up to the game — it changed a lot throughout the week — but he’s confident the Levi’s Stadium surface is ready for its moment in the playoff spotlight.
After all, the surface is greener and healthier than it’s ever been at this time of year thanks in part to a new tool in Greiner’s arsenal, a bank of grow lights that arrived in mid-November. Anyone who peeked inside the stadium around that time might have thought a spaceship had touched down on the field. The lights are neon pink and cover a third of the field.
Greiner said the movable rigs contain red- and blue-light waves that encourage photosynthesis, as well as infrared lights that help warm the surface temperature. Which is to say, they help the grass grow.
Green grass and red end zones: Levi’s Stadium gets ready for the playoffs… pic.twitter.com/46rR06c5qg
— Matt Barrows (@mattbarrows) January 18, 2024
Nick McKenna, the assistant athletics director at Texas A&M and the former president of the Sports Field Management Association, said the technology has its roots in the Netherlands, where it was used to help tulips grow in low light. Major League Soccer has used grow lights for a while on its pitches with NFL teams like the Chiefs and Baltimore Ravens catching on in recent years. Even the Miami Dolphins use them because the awnings inside Hard Rock Stadium, designed to shield fans from the hot South Florida sun, also rob the field of sunlight.
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“We’ve got these newer stadiums where a lot of it is about the fan experience,” McKenna said. “You want the fans covered and protected from weather. So they’re building them more vertical where you’re creating these unprecedented shade lines. And at the end of the day, grass is a plant. It’s got to have a certain amount of light.”
Even a wide-open stadium like Levi’s doesn’t get enough light in the winter. The suite tower on the west side of the venue blocks a lot of the light, and the warm-weather Bermuda grass that makes up the bulk of the Levi’s playing surface typically goes dormant in late November.
The grow lights are designed to keep it awake a little longer. Greiner said the north side of the field gets more natural light than the south side, which is why the grow lights have spent more time on the south end of the field. He said sensors in the field that measure everything from light to soil temperature to moisture content suggest the grow lights are working. So do less scientific methods such as how often his crew has to cut the grass or how much paint is needed in the end zones, logos and other areas.
“We’ve never had a better stand of grass in the south end zone,” Greiner said. “We’ve never grown out of paint as much as we have in the south end zone. It’s been drastically different.”
The Levi’s playing surface got off to a famously rocky start when it was first installed in 2014. Then-head coach Jim Harbaugh had to cancel a practice because swaths of grass were being dislodged. A season later, it looked as if Ravens kicker Justin Tucker had been swallowed by the field when a chunk of grass gave way on a field goal attempt.
Recently, however, the field has been one of the more stable surfaces in the league with consistently strong reviews from 49ers players. Defensive end Randy Gregory, who’s had stints in Dallas and Denver, called it “one of the better fields I’ve played on.”
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“I don’t feel sluggish on it,” he said. “It’s short enough to feel fast and high enough that we can sort of plant (our feet) in and not feel like it’s concrete.”
Greiner said the grow lights will never be able to replicate the summertime sun. But he said all of the measurements he makes — including the rotational resistance of the grass, which essentially determines how it will hold up to the pounding of a three-hour football game — have remained higher this winter than they have in the past.
The field also hasn’t been under the same stress it endured in 2019, the last time the 49ers had home-field advantage throughout the playoffs. That December, the stadium hosted two 49ers games as well as the Pac-12 championship (Dec. 6) and Redbox Bowl (Dec. 30).
Levi’s didn’t host any college games in December 2023. And the 49ers have used the same surface since Ed Sheeran played at Levi’s on Sept. 16, a Saturday. New grass was rolled in on the Monday and Tuesday after the concert, and the 49ers hosted the New York Giants on Thursday. Greiner said he swapped out what he calls the “gut” — the well-trafficked section between the numbers — after the Rams game on Jan. 7. Because of that, he said the field might not have the aesthetically pleasing golf-course look it had on, say, Oct. 8, when the Dallas Cowboys visited.
But it ought to play well.
“If you’re starting off with a superiorly strong stand of grass, and then you add in the elements such as the grow lights, that’s how you can sustain these fields,” he said.
(Photo courtesy of Terrell Lloyd / San Francisco 49ers)
