Why did designing the World Cup pitches take eight years?

Summary

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Short Wave – Episode Summary

Episode Title: Why did designing the World Cup pitches take eight years?
Air Date: July 17, 2026
Host: Nate Rott (for this episode)
Guest: Dr. John Sorokin, Professor of Turf Grass Science, University of Tennessee

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Main Theme and Purpose

This episode of Short Wave dives into the intricate and fascinating world of turf grass science, spotlighting the eight-year-long process of designing and preparing the pitches for the 2026 World Cup. Host Nate Rott and turf expert Dr. John Sorokin unpack the science and engineering behind creating uniform, resilient grass playing fields across 16 diverse stadiums. Beyond the soccer spectacle, they explore how these advances might trickle down to community parks and everyday playing fields.

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Key Discussion Points and Insights

The Challenge: Sixteen Stadiums, One Standard (03:07–04:11)

• Consistency was King: Dr. Sorokin was mandated to ensure all pitches—across indoor and outdoor venues, differing in climate and altitude—remained uniform through 104 matches over six weeks.
  • “He wanted consistency, uniformity across the different venues…We don't want to have to replace any grass during the tournament.” — John Sorokin (01:01)
  • The fields had to withstand heavy, repeated use without mid-tournament repairs or re-sodding.

The Science Behind Stadium Grass (04:11–06:08)

• Technological Evolution:
  • In 1994, grass was grown in parking lots and transported inside domed stadiums, only to fade after weeks without sunlight.
  • In 2026, five indoor venues utilize advanced LED grow lights for “daylight replacement.” Stadiums glow red at night to nurture the grass.
  • “If you drive by these stadiums at nighttime, they're lit up red because they've got these LED grow lights. Growing the grass indoors to replace the sunlight.” — John Sorokin (04:22)
• Hybrid Turf Innovations:
  • Required sand-based root zones and synthetic ‘rebar-like’ fibers reinforce the natural grass, reducing divots and improving stability.
  • Vacuum ventilation allows rapid water drainage—even during torrential rain, pitches stay dry and playable.

Player Safety, Uniformity, and the Art of Pitch Engineering (06:08–09:13)

• Uniform Playing Surface: Essential for fair competition and player safety. A poor surface can affect game outcomes, risk injury, and ruin the spectacle.
  • “If it was a crappy field, they’re going to talk about it…We don’t want to compromise the outcome of the game because of the surface that they’re playing on.” — John Sorokin (06:45)
• Surface Science: Consistency in turf prevents injuries—“not too hard and not too soft”—and ensures reliable ball and player movement.
  • Player, surface, and footwear form a triangle:
    • Different grass types (warm/cool season) across venues demand tailored cleats—like F1 cars switching tires for changing conditions.
  • Testing includes a custom robot foot/strike device to simulate real player interaction with the surface, gathering data to help coaches and equipment managers choose the right gear.
  • “We developed a machine…It tells us the forces that the athlete's feeling vertically, horizontally, laterally…so we can educate players and coaches…” — John Sorokin (08:14)

Tropical Miami to Dome Stadiums: Grass Logistics & Climate Considerations (09:13–10:24)

• Grass Matching and Moving:
  • Grasses chosen are native to each stadium’s climate—cool season for Seattle (ideal between 60–75ºF); warm season for Miami.
  • For extreme climates (e.g., Houston), sod couldn’t be grown locally, so it was cultivated on plastic in Denver, then refrigerated and shipped to stadiums—ensuring healthy, ready-to-root turf.
  • “We actually grew it in Denver…Then shipped it to Dallas, Houston, and Atlanta…harvested at nighttime, put them in refrigerated trucks…” — John Sorokin (09:42)

Getting the Goldilocks Grass (10:24–12:24)

• Performance Matching:
  • Experiments with different mowing heights and ball rebounds ensured cool and warm season grasses offered the same ball behavior—uniformity by scientific measurement.
  • “We launched soccer balls at an angle…so the ball comes in, it's going to bounce at the same angle and the same coefficient of restitution.” — John Sorokin (10:41)
  • Adjusting mowing frequency, growth regulators, and fertilizer for just the right growth and durability.
  • “It's actually really simple. Don't mow it too infrequently. Don't mow it too short and don't mow it too high.” — John Sorokin (11:41)
• All About the Grass Family: Turf grass is not only crucial to sports but humanity due to its resilience and regrowth—unlike wheat or corn.

Innovation and a Trickle-Down Effect (12:24–13:25)

• Legacy Beyond the World Cup:
  • Innovations developed for elite play can improve local parks and fields, enhancing safety and field quality for youth and amateur athletes.
  • “How do we help the average city park and rec field to get better and safer for…our children that are playing on them. Right. I think that’s, to me, one of the great outcomes…” — John Sorokin (13:16)

Whom Does the Turf Scientist Cheer For? (13:25–13:55)

• Pitch Pride:
  • John Sorokin, when asked which team he’d support, jokes:
    • “I'm cheering for the pitches now, first and foremost.” — John Sorokin (13:40)

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Notable Quotes & Memorable Moments

• On Turfgineering:
  “You're describing like a cyborg grass.” — Nate Rott (05:22)
  “Yes, absolutely.” — John Sorokin (05:28)

• On the Impact:
  “…the most important athletes, which is our children that are playing on them.” — John Sorokin (13:19)

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Important Segments & Timestamps

• [00:44] Meet the guest: Dr. John Sorokin, his background and path to turf science
• [04:11] Evolution of turf technology—LED grow lights, sand-based roots, hybridization
• [06:28] Why field quality matters (safety, fairness, spectacle)
• [08:14] Robotic “foot strike” machine and data for player equipment
• [09:42] Growing and transporting sod tailored for different venues
• [10:41] Balancing grass species, mowing, and fertilizer for uniform ball play
• [12:24] The potential impact on community-level sports fields
• [13:40] “Cheering for the pitches” moment

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Tone and Experience

• The conversation is lively and playful, with Nate Rott bringing humor and curiosity (“Do your friends call you Mr. Turf?”), and Dr. Sorokin infusing passion for turf science (“The grass family is the most important family of plants in the world, I would say, because of turf grass.”).

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For Listeners

Whether you’re a soccer fan, engineering buff, or local park enthusiast, this episode reveals the surprising complexity, scientific rigor, and dedication required to create the literal playing field for the world’s top sport—offering a new lens through which to appreciate every patch of green you see, from World Cup stadiums to your own neighborhood park.

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Transcript

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[Nate Rott]

Short wavers, maybe tall waivers. I don't know who you are. What's up, Nate? Rod here. If you've been watching any World cup games and how could you not, because they're on everywhere. There's something you probably haven't appreciated enough and no, it's not the players.

[John Sorokin]

So my name's John Sorokin. I'm a professor at the University of Tennessee and I specialize in turf grass science.

[Nate Rott]

Turf grass science? Yes, it's a thing. And for this World Cup, John had a pretty remarkable mandate from the guy managing the pitches or fields the games are played on.

[John Sorokin]

He wanted consistency, uniformity across the different

[Nate Rott]

venues, indoor fields and outdoor fields.

[John Sorokin]

The one thing he said is we don't want to have to replace any grass during the tournament, which means going in and resoding a stadium or even a goal mouth. We don't want to change any of that.

[Nate Rott]

Meaning the fields had to hold up for 104 matches over six weeks.

[John Sorokin]

16 completely diverse stadiums from Mexico City at really high altitude to the same indoors in Vancouver at sea level and the same as at a tropical Miami. How do we get these to be the same? As close to the same as possible after, you know, a big gulp. My sleepless nights for the next eight years began.

[Nate Rott]

So today on the show, the science that's gone into the playing fields for this year's World cup and what it might mean for a community park near you. You're listening to Shortwave, the science podcast from N.

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[Nate Rott]

All right, John. I'm kind of tempted to call you Mr.

[NPR Fundraising Announcer]

Turf.

[Nate Rott]

Do your friends call you that?

[John Sorokin]

No, you don't want to know what my friends call me, but yeah, that's okay.

[Nate Rott]

How do you get into something like this? You've been doing this for 30 years.

[John Sorokin]

Yeah, by accident. I started off at the University of Calgary thinking I'd be a lawyer in the oil and gas industry, and I did not like it. So I went and got a job on a golf course and I fell in love with it and I transferred to Michigan State University and that's when that World cup was here. I started working on that in the late fall of 92 as a student. And we got to go on the roof of the Silver Dome when the whole tournament was over and jump on it like a trampoline. It was air inflated, right? And then lay down and you're like, holy, I'm a couple hundred feet above the ground. I started looking at the field and you could see after a month indoors with no sunlight, it was showing its wear. And I was like, how do I make that better? How would we make this all uniform? And so I went on, and my PhD was growing grass indoors for dome stadiums. And now doing it, you know, 32 years later for the 20, 26 World Cup.

[Nate Rott]

Is there anything that you guys are doing this year that's different than what's been done in the past?

[John Sorokin]

Yes. Five of the 16 stadiums are indoors. First time this happened actually was in 94 or 32 years ago when the World cup was here. We didn't have the technologies we have today. So we grew the grass in the parking lot and then we put it inside. And for the next 30 days, it started declining because there's no sunlight. Fast forward 32 years. We got five dome stadiums and they've got grow lights in there. So if you drive by these stadiums at nighttime, they're lit up red because they got these LED grow lights. Growing the grass indoors to replace the sunlight.

[Nate Rott]

I'm curious, you know, spending three decades in this field, like how has the science evolved from when you first started till now?

[John Sorokin]

Yeah, well, Jesus, make me feel old when we call it three decades.

[Nate Rott]

We're not aging nobody.

[John Sorokin]

Yes, it's changed a lot. So FIFA has these requirements. You have to have a natural grass pitch that has a sand based root zone, that has an in ground irrigation system. And in that sand root zone, they have to be hybrid Reinforced with synthetic fibers that go in and kind of like act like rebar. So when you go and you, you plant, you're not getting a big divot below out because it stabilizes it below. But the top you're playing on is all grass. But those fibers are stabilizing that sand below.

[Nate Rott]

Whoa. It's like mutant grass. You're describing like a cyborg grass.

[John Sorokin]

Yes, absolutely. If you've watched some of the World cup games that have happened, there's been a lot of rain events.

[Nate Rott]

Yeah.

[John Sorokin]

And that's why they're sand based root zones, so they drain rapidly. But also they have what's called a vacuum ventilation system where they can actually create a suction and pull water out. So there's never standing water on these pitches. England and Mexico, besides being an amazing game.

[Nate Rott]

Yeah, it was.

[John Sorokin]

It had been raining all day and all leading up to the game and even during the game and there wasn't a bit of standing water and the pitch was perfect. So that's because of these requirements that FIFA has and these are all new since the 94 World Cup.

[Nate Rott]

You were describing the most like, complicated, sophisticated field that I, more than I could even begin to comprehend.

[John Sorokin]

Right? Yes. I just want to know, did I ruin it for you? Now, when you watch the next game, are you going to be watching the pitch or are you going to be watching the match?

[Nate Rott]

I mean, since we've been prepping for this story, I've definitely been paying more attention to the pitch. I think a lot of people watching these World cup games might be surprised to hear what an important role the grass field plays. Why is it so important?

[John Sorokin]

Well, when you think of everything that goes into putting on something like this, whether it's the super bowl or the World cup, you've got these immaculate stadiums. You got to make sure you have the hotels for people and you've got the concessions and the skyboxes, everything.

[Nate Rott]

$30 hot dogs.

[John Sorokin]

Yeah, whatever it is, everyone's there to watch the game. And what's most important about all of these things is what the game's being played on. If it was a crappy field, they're going to talk about it. And if it was bare and the ball was bouncing wrong or players going to stop and he blows out a big piece of grass or he slips and falls, that's not good. We don't want to compromise the outcome of the game because of the surface that they're playing on. We want those players to have the perfect canvas that they can have to orchestrate their game and Demonstrate their abilities at the highest level.

[Nate Rott]

I'd assume it has something to do with player safety, too.

[John Sorokin]

Yeah, absolutely. We focus for our safety guidelines is consistency and uniformity. Not too hard and not too soft, not giving you way too much traction, and not being where they're going to slip and fall. Also, because there's three components when it comes to the player safety. There's the player, there's the surface, and then there's the footwear. And if you watch F1, they've got hard, medium and soft tires for the F1 car that they race on, depending on the conditions of the track. And then if it's raining, they put on slicks. If you think of a World cup soccer player as an F1 car, depending on the surface. Because we have warm season grasses and cool season grasses. Because in Miami they're going to grow warm season grass. In Boston they got a cool season grass. Well, you probably want different tires or treads or cleats on those surfaces. So you get the same performance on those two surfaces.

[Nate Rott]

It's like you're setting the stage for one step of this process, but then the players and their coaches and their equipment managers are doing the next phase.

[John Sorokin]

Yeah. And we want to provide evidence based data. We developed a machine at the University of Tennessee that actually simulates a foot strike. And we can get a heat map of a soccer field going up and down it. And it tells us the forces that the athlete's feeling vertically, horizontally, laterally, their level of traction, the time to get to their peak performance, and a rebound effect if there's any bounce back that they're feeling. And so we can educate players and coaches and equipment managers.

[Nate Rott]

Does this device look like a footprint? I'm imagining like a robot foot.

[John Sorokin]

It is. Well, the device is big, and then inside it's got a 3D printed foot. Then you put the shoe on it and it strikes down the surface.

[Nate Rott]

Is it like a mock up of your foot?

[John Sorokin]

Yeah, no, we want to use elite athlete's feet. So we got.

[Nate Rott]

Your foot isn't an elite athlete foot.

[John Sorokin]

That ship has sailed.

[Nate Rott]

Yeah, yeah, my ship sailed too. So from my understanding, the transformation process for each stadium was different. So what were all the factors that went into determining, you know, which combination of grass was going to be best for each place?

[John Sorokin]

So we. What grasses grow in each region, and that's where they're done. The cool season grasses grow best between 60 to 75 degrees. So we can look at Seattle. That's going to be ideal. We got five dome stadiums. They're indoors. Inside it's 70 degrees. We're going to put the cool season grass inside, but it's 95 degrees in Houston. So you can't grow the sod for Houston in Houston because it's too hot outside. So we actually grew it in Denver.

[Nate Rott]

What? And then shipped it to Houston.

[John Sorokin]

The sod was planted a year before in Denver on a sod farm. It was growing on plastic. And then we shipped it to Dallas, Houston and Atlanta from Denver, and they harvested at nighttime, put them in refrigerated trucks, drive it whatever distance they had to go. And the nice thing about the Sodom plastic is it's growing in the exact same sand as what's in the stadium. So we can come and cut it like a pizza, roll it off of the plastic and you've got these healthy roots all intact. And when we go late in the stadium on the sand that's below. Roots grow by gravity. It's called gravitropism. And it establishes faster. And you've got one less stress that you didn't add by cutting off all of its roots. That's how it gets its water and nutrients.

[Nate Rott]

The amount of thought that goes into this is you've blown my mind like 42 times already. So, John, like you've described needing different types of grasses for different climates, which makes sense, but if the goal is uniformity.

[John Sorokin]

Yeah.

[Nate Rott]

How do you make sure that one type of grass performs at the same level as another?

[John Sorokin]

I had a grad student that did work where we launched soccer balls at an angle at like 50 miles an hour and then it bounces. And we had high speed cameras and we tracked it and we found what's the mowing height for the cool season grasses versus the warm season grass. So that when the ball comes in, it's going to bounce at the same angle and the same coefficient of restitution. I had my students, undergrads, putting on soccer cleats and running back and forth doing high steps. If we're not abusing the grass and killing grass, we're not testing its limits. And so we do a lot of that simulation of traffic and abuse. And then we look at just things like plant growth regulators to slow the vertical growth but increase the density and the rigidity of the grass. And we look at different nutrition of nitrogen, fertilizer balances. That's what's the driving force. We don't want to grow too fast because it makes it more lush, but we don't want to grow so little that it's not going to recover when it does because you abuse it. It's a living organism. It will die and it needs to recover. And so we're looking at that balance.

[Nate Rott]

Like the Goldilocks amount of nitrogen.

[John Sorokin]

Exactly. It sounds all really complex, but it's actually really simple. Don't mow it too infrequently. Don't mow it too short and don't mow it too high. And the nice thing about grasses is when you mow it like any other plant in the world, you can't do this to. The grass family is the most important family of plants in the world, I would say, because of turf grass.

[Nate Rott]

Objectively, you would say yes, objectively, Nate.

[John Sorokin]

I'm 100% objective of those grasses. We got rice, corn, wheat, you know, millet. Those are the main staples of the world's diet. Right. You can't go and cut off a wheat field every day. It's not going to grow back or cornfield. But you can with the turf grasses, and that just gets them to actually grow up and put new leaves. So that's what's unique about turf grasses.

[Nate Rott]

Man, I want to be a grad student for you. Can I come do that?

[John Sorokin]

Absolutely.

[Nate Rott]

What impact do you hope that this will have on future World Cups and like other sporting events? Because turf is important, and just about every sport we play is humans.

[John Sorokin]

Yeah. So I think it sort of increased the awareness of what goes behind it. A lot of the research we've done that FIFA did wasn't even used in this World cup, but it's done a lot of innovative things. We developed and we worked and we proved the concept of what's called a shallow pitch profile, where we just now showed that you can come in in a short period time and put a nice natural grass field in, play a game in, take it out, and you can get ready for the motocross or the truck and tractor pull or Taylor Swift or whatever you want. That's really cool. And then just some of the other stuff that's going to have the legacy and trickle down. There's all sorts of things that. How do we help the average city park and rec field to get better and safer for maybe what we might consider the most important athletes, which is our children that are playing on them. Right. I think that's, to me, one of the great outcomes that's come from this and that will continue to go as we disseminate the information that we've gained over these last several years of doing research.

[Nate Rott]

Yeah, Jon, we're taping this before we know who's in the final, but by the time this airs, we should know who the final two teams are. Are you polling for anybody in particular?

[John Sorokin]

You know, as a Canadian, I was obviously cheering for Canada, but I love all the teams. I'm cheering for the pitches now, first and foremost.

[Nate Rott]

Well, I'm going to take a note from your book, John, and I'm going to just cheer for the grass.

[John Sorokin]

Yep.

[Nate Rott]

Well, John, thanks so much for doing this, man. It's really cool. I've learned a lot and thank you. I have a whole new appreciation for what I'm watching on TV now.

[John Sorokin]

Absolutely. Thank you for reaching out and wanting to do this. This has been a lot of fun.

[Nate Rott]

If you're a soccer fan who just listened to this episode because it's about the World cup or you're a fan of sports, I think you'd love some of our other stories on the science behind your favorite athletics, like our story on the physics of ice skating. For more science stories just like these, follow shortwave on the NPR app or wherever you're listening from. This episode was produced by Aru Nair. It was edited by our showrunner, Rebecca Ramirez. Tyler Jones checked the facts. Robert Rodriguez was the audio engineer. I'm Nate Rott. Thanks for listening to Short Wave, the science podcast from npr.

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