Sports-Field Mowing Excellence

By Randy Gaddo

This column, “LBWA” (Leadership By Wandering Around), is based on the premise that, in order to find out what’s going on in the field, a parks and rec leader has to leave his or her desk and “wander around” the area of operations, talk to people, ask questions and kick around ideas with the individuals in the thick of delivering services to the public.  So the author will bring up issues that may be common to many PRB readers and ask the leaders who are the readers to weigh in and share their knowledge and experiences. 

Parks and recreation maintenance crews tasked with mowing sports fields often have choices: just get the basic job done and mow the turf at least once a week—twice in heavy growing seasons, if they’re lucky; or move the mowing to a higher plane.

The move toward this higher plane may involve varying mowing techniques using different equipment and at the highest level, and include a pattern in the field.

I know there are maintenance pros shaking their heads ruefully as they read this and are saying, “Yeah, dream on, we wish we had the time, staff, and budget to make those beautiful patterns you see on college and pro fields.”

Well, OK, I accept that skepticism, and it is justified—but let’s do a little dreaming and see where it takes us.  Who knows, there may be some middle ground where time-and-money-strapped parks and rec pros can transcend the obvious obstacles and at least step up a rung or two on the hypothetical ladder.

Just The Basics
Mowing turf is more than merely keeping the grass cut; even at a basic level it is one of the most critical cultural practices a turf manager can perform. A properly mowed field will:

• Help control weeds naturally
• Produce better moisture stress tolerance
• Generally have better quality than improperly mowed turf. 

The end result will be more satisfied customers.

“Safety and playability must always be the priority goals for a field,” notes Steve Wightman, retired Field and Operations Manager at QualComm Stadium in San Diego, and past president of the Sports Turf Managers Association. Wightman also worked in parks and recreation earlier in his career, managing 250 sports fields for the Denver, Colo., parks and rec department.

Wightman says that when parks and rec field users watch college or professional sports on TV, they want their fields to look like that—groomed, precisely mowed, and often with a pattern in the field.

“That is a challenge for most parks and rec departments,” notes Wightman, conceding that limited staffing and budget plus intense field usage works against the goal of grooming each and every field.

But perhaps it is possible to start with a field or a grouping of fields as a pilot project. “Sometimes it helps to try new things on just one field to show what can be done,” Wightman suggests.

There are several considerations that parks managers and crews should think about to ensure the return on investment of time and funding. These include:

• Type of mower used
• Mowing height
• Mowing frequency
• Mowing direction
• Disposal of clippings.

Type of Mower
There are two types of mowers—rotary and reel.

Rotary mowers are the standard type that people generally use on their lawns. The blades rotate horizontally, slicing the grass blades parallel to the ground. If the blades are very sharp and free of nicks, and if the mower deck is level and set at the correct height, rotary mowers can give a good cut on sports fields.

A reel mower has several rotating blades, paired with a single, stationary back blade. The back blade—sometimes called a bed knife—is usually fixed at the base of the rotating cylinder between the wheels. The rotating blades rotate towards the stationary back blade, gathering up loose stalks of grass as they turn through their arc. When the back blade brushes against the spinning blades, it cleanly cuts any grass or weeds caught in between.

Again, blades must be sharp, level, and at the correct height. It is generally accepted that reel mowers give a better mow because they are actually cutting the blades of grass like scissors rather than with the pulling and ripping motion of the rotary blade. Reel mowers are used for a fine cut where grass has to be very short, such as on a putting green or soccer field.

Most people will agree that reel mowers are preferable on sports fields. However, these mowers are more expensive to purchase and more maintenance-intensive, in that the blades must be kept very sharp to be effective. Using reel mowers for any cutting other than sports fields is not wise because any rocks or debris will quickly dull the cutting surfaces, and sharpening the reel blades can be expensive, requiring special equipment and skills. This job is often outsourced.

Rotary mowers are less expensive to purchase, and normally blades can be sharpened in-house. It can be argued that, if properly maintained, rotary mowers can adequately work for parks and rec sports fields.

“However, you should try if at all possible to dedicate specific mowers just for sports fields,” says Wightman, acknowledging that isn’t always easy or possible due to limited resources. Common areas are not generally cut to the same standards as sports fields. “If the same mowers are used for sports fields and common areas, blades can be dulled more quickly, and decks can get unbalanced cutting across uneven common areas.”

Mowing Height
The question of how high to cut grass isn’t a “one-size-fits-all” proposition. It is dependent on several factors, such as climate, type of turf, time of year, amount of rainfall, health of the turf, and several other circumstances.

However, as a rule of thumb, Wightman suggests the “one-third” rule. “Never cut more than one-third of the total grass blade length at any one cutting,” he notes, conceding that this is also driven by circumstances.

“After a long period of rain where you can’t mow and the grass grows too tall, it is tempting to get out and mow it all down at once,” he says, pointing out that this will leave excessive thatch on the ground, making the fields unsightly, less playable, and possibly unsafe.

One easy solution is to raise the mower height on the first pass and then do a second pass, at a different angle and at a lower height. This takes more time and gas but will more evenly distribute the thatch, make the fields more playable and safer, and cut down on customer complaints.

There are so many different types of turf developed specifically for certain climates that it is impossible to outline the prescribed mowing heights in this column. Local county extension services or university turf experts are often good sources of no-cost advice on regional turf treatment.

Mowing Frequency
How often to mow is another area where desire meets reality and reality often wins. In a perfect world, it is desirable for recreational sports fields to be mowed at least twice a week. In recreation reality, it is a good week when it is done once.

Mowing frequency is important to ensure healthy turf and reduce the accumulation of clipping debris on the playing surface, declare Pam Sherratt and Dr. John Street in a co-authored article. Sherratt is a sports turf specialist at The Ohio State University and served on the Sports Turf Management Association board of directors from 2010 to 2011. Street has been a professor in turf-grass science at The Ohio State University for about 30 years.

They concur with the one-third rule. For example, if the desired grass height is 2 inches, grass should be cut when it is 3 inches. “Removing more than one-third of the leaf surface at one time results in an open, stemmy appearance of the turf, weakens the grass plant, reduces or stops root growth, and leaves significant clipping debris on the surface. Clipping debris can be unsightly as it dries on the surface and may also interfere with play,” they propose in the Sports Management magazine article.

Mowing Direction
Changing the direction of mowing is probably one of the most-overlooked but simplest and most effective practices field managers can undertake.

“Mowing at different angles prevents a ‘grain’ caused by mowing in the same pattern week after week,” says Wightman. “When you mow in the same direction, the grass leaf lays down in one direction so the sun isn’t able to hit the leaf tissue uniformly. Every time you mow, you should change direction to ensure the leaf is fully exposed.”

Changing direction of mowing doesn’t cost the parks and rec field pro any more time or money but can make a significant improvement to turf health.

Direction of mowing is also important to create patterns on the field.

What To Do With Clippings
Most parks and rec sports fields are “native soil” fields—that is, they are not augmented with a sand layer and drainage utilities that enable the water to drain through more quickly. For the most part, they are built with the soil that is native to that geographical region, and water is either runoff or perked through naturally. It is a generally accepted best practice to keep the clippings on the native-soil fields, as long as the one-third rule is followed to avoid excessive accumulation of clippings.

“Organisms, such as earthworms, arthropods (i.e., insects, arachnids, crustaceans), and fungi in the native-soil environment, quickly break down clippings, so no hydrated clipping layer forms,” write Sherratt and Street. “Turf-grass clippings contain measurable amounts of nitrogen, phosphorus, and potassium, so they're beneficial to the turf.”

Research has shown that when clippings are removed, 20 to 25 percent more fertilizer is necessary to maintain comparable color and quality, as compared to areas where clippings are returned. One hundred pounds of grass clippings can generate and recycle as much as 3 to 4 pounds of nitrogen, .5 to 1 pound of phosphorus, and 2 to 3 pounds of potassium back to the turf, according to Sherratt and Street.

Sand-based fields are specifically maintained to minimize organic material build-up, which can cause a soft, spongy, slick playing surface.

Sand-based fields are generally more expensive to build and require unique maintenance practices, and therefore are normally not found in the average parks and rec field inventory. They are normally seen on tournament fields, college inventories, or in the professional leagues.

Patterns: The Next Level Up
Once the basics are in place, the next level is mowing patterns into the field. David Mellor is the Director of Grounds for the Boston Red Sox baseball club and manages fields at Boston’s famous Fenway Park. He is recognized as one of the best in the business, not only in professional sports-field operations but also as a pattern expert.

“Some artists use canvas to create a work of art. David Mellor uses a baseball field,” Bob Uecker, Milwaukee Brewers broadcaster, once commented. “His patterns are so precise and imaginative, I call him the Rembrandt of groundskeeping.”

“People have one opportunity to make a good impression,” suggests Mellor. Whether it is a basic checkerboard pattern or a more complex design, he says, “Patterns don’t take that much more time than just mowing. People can do things for tournaments, or for holidays or special events that captures someone’s attention to help make that first impression and really add to the aesthetics.”

Mellor explains that it is much better to mow in a pattern or design rather than painting it in. Mowing is not so lasting and can be changed or corrected more easily, plus mowing is something that has to be done anyway. Of course, his designs are much more complex than most parks and rec departments would ever attempt.

The easiest fields on which to mow patterns are arguably football fields, where natural, straight, and parallel lines are demarked by yard lines. Simply mowing in opposite directions, sideline to sideline, every other yard line, will give the appearance of a light and dark pattern. Grass blades will reflect light differently depending on which side of the field one is looking from; blades lying away from one’s sight will reflect light and appear lighter, while blades lying towards one will absorb light and look darker. Soccer fields can be done similarly, only mowing end to end instead of side to side.

An entire field doesn’t need to have a pattern, just selected areas. On a baseball field the outfield might be mowed in a standard arcing pattern following the fence line; then intersecting lines perpendicular in the arc can be mowed from the infield towards the outfield fence, back and forth, spaced widely enough to minimize extra mowing but enough to show a unique pattern. A simple checkerboard can be done on the infield, mowing perpendicular, straight lines from baseline to baseline.

It may seem like the grounds crews who create the patterned masterpieces seen at college and pro games must be using high-end equipment. Not so, says Mellor.

“Many people think you need a high-end reel mower to mow patterns because they already have rollers on them,” notes Mellor, adding that the rollers automatically flatten down the grass blades after they are cut, enabling a pattern to be formed. But he notes that some rotary mowers come with rollers attached. One example is Simplicity, the mowers he uses at his home and at Fenway. They feature free-floating mower decks with full-width rollers.

Rollers are really the key to making patterns while not adding significantly to mowing time or complexity. Rollers force the grass blade to lay down in a given direction to give a lighter or darker appearance.

Mellor explains that rollers can be made to retrofit onto any rotary mower. In his book, Picture Perfect: Mowing Techniques for Lawns, Landscapes, and Sports, he gives step-by-step directions on how to construct these homemade rollers from PVC pipe.

In the book he describes other methods of field designs and methods, including use of water to lay the grass blades down.

“I think people want to take great pride in their work but sometimes they just don’t have the knowledge to create a pattern,” notes the pattern guru. “We all need suggestions sometimes.” He provides suggestions on many different mowing techniques in his book.

Randy Gaddo served for 15 years as a director in municipal parks and recreation after retiring from 20 years in the U.S. Marine Corps. He developed, wrote, administered, and presented maintenance plans as well as recreation master plans during that time. Gaddo earned his Master’s in Public Administration, and now lives in Beaufort, S.C. He can be reached at (678) 350-8642 or email cwo4usmc@comcast.net.