How Wimbledon Dictates Grass Court Speed

The 9,709 square feet of Wimbledon’s Centre Court grass—not to mention the other 17 championship courts and 20 grass practice courts—take on a singular focus during the two-week The Championships, but it’s a year-round effort to care for the world’s most famous sward (a fancy term for an area of short grass).

Every court gets a renovation in September—the All England Lawn Tennis Club uses over nine tons of grass seed annually—with a focus on creating durability during the two-week event. And while there’s only so much that the group of 15 permanent ground staff at the club—an additional 13 temporary staff are added for the tournament—can do with the amount of use the ryegrass courts receive, the focus is all about durability and consistency.

Determining the speed of the court, which gets tested daily, comes down more to the soil than the actual grass, which is cut to eight millimeters daily. The general compacting of the soil over time, as well as the weather leading into the tournament and each day, are the major factors in how the ball responds.

“The amount a ball bounces is largely determined by the soil, not the grass,” Wimbledon reports. “The soil must be hard and dry to allow 13 days of play without damage to the court sub-surface. To achieve the required surface of even consistency and hardness, the courts are rolled and covered to keep them dry and firm.”

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All courts get re-lined with a mix of titanium dioxide via a transfer wheel marker, rolled and mowed daily during The Championships.

While the September rebuild really starts the process for the next summer’s The Championships, preparations begins with a skimming of the top roughly 12 millimeters. Think of this as a severe balding.

“This removes all weak and weed grasses from the sward, and it reestablishes the levels where play has worn the surface,” says Will Brierley, Wimbledon senior groundsman. Crews till a seedbed to lay new seed and fertilizer. It takes about one ton of seed each year. Covering the courts with a semi-permeable translucent growth cover for up to a week regulates heat and moisture. A program of mowing in the fall helps firm the surface and levels the grass before receiving a top-dressing of fine soil — about six tons total — and dragging to ensure the perfect leveling of the soil.

In 2001, the All England Club switched from a mixture of 70 percent ryegrass and 30 percent red fescue to a 100 percent ryegrass for increased durability, as suggested by the Sports Turf Research Institute in Yorkshire, UK. The ryegrass contains up to three different cultivars to make for a dense sward with improved bounce.

This famed ryegrass sits above a “seedbed” of drainage pebbles, drainpipes, small stones and course soil.

Prepping for The Championships, Wimbledon intensifies in spring. A post-winter roll removes frost, and a spraying program starts in April to help with plant growth, durability, color and root development. “The date of this is worked back from the tournament start date to enable us to maximize the application,” Brierley says.

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Since March, the sward height drops about one millimeter every two weeks. Millimeter by millimeter, weather dependent, of course, the overall height of cut for The Championships slices from a hefty winter growth of 13 millimeters down to the playing elevation of eight millimeters, the height of the sward for play since 1995. At the playing height in time for Members’ Day in May, the ryegrass can adjust to the stress of its height before the stress of trampling begins.

The marking of the courts begins in early May and during the playing season the grass is cut every other day. In June, crews start to restrict the amount of water put on the courts to help the soil firm up, ensuring hard and dry soil for The Championships.

During the two-week tournament, daily care of the courts includes measuring wear and hardness. The grounds crew tests soil moisture content, court hardness wear and plant chlorophyll levels to dictate evening watering amounts.

“The tests will determine,” Brierley says, “how much irrigation is needed at the end of play to keep the grass alive and keep the court firmness at a playable reading.”

Early every morning, Wimbledon courts receive a mow from a Toro cylinder mower and marks from a wheeled machine that lays titanium dioxide 50 millimeters wide for the lines — 100 millimeters for the baseline. It takes 500 gallons each year to mark all the lines. And Rufus, a trained Harris Hawk, patrols the grounds to ensure pigeons stay off the lawns.

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The practice courts get their care in the evening, allowing players to get on the courts early each day. All championship and practice courts receive the same level of care to give equal playability “as close to humanly possible” across the site. The only special need includes a machinery lift to get equipment onto No.2 Court.

About a week in, the grounds crew uses a machine dubbed the Billy Goat to essentially vacuum and clear off any kicked up debris from a week of play. Unlike the clay courts at Roland-Garros, the Wimbledon courts don’t receive any care during play, except to cover from rain as needed.

Whether Centre Court or a practice court, the bounce of the ball at Wimbledon is a carefully crafted effort to manage a living plant.

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