Tips From The Pros

THE DENVER 10 MOWING PATTERN

When you click on the TV and plop yourself down to watch a good sporting game played on natural grass, you likely have no idea of the details that the field manager sweats out each and every game.

One of the things that makes a good natural grass sports field stand out from lawns and such is a crisp, vivid mowing pattern. Compared to our lawn grass, a sports field is generally mowed at a lower height of cut and usually with a reel-type mower or one of the modern HQ rotary deck mowers that will lay the grass over a bit from rollers on the mowers. This grain plays with sunlight and produces a light-dark tint that tends to “stripe” the stand of turfgrass as it is mowed back and forth. Different ballparks and stadiums use different mowing patterns and some of these, especially in baseball can get really creative. Some are even unique to the ballpark or stadium. Dave Mellor, one of the gurus of mowing patterns, even wrote a book about the subject. The Sports Field Management Association (SFMA) has held a mowing pattern contest in recent years.

On the other hand, football fields across America sadly cannot find that creative purchase, no one admires a football field mowing pattern like they do a baseball/softball field. For one simple reason I’ll explain down the line, football fields have pretty much been mowed using the same basic 5-yard block pattern since the 1960’s at least.

The Creation.

This changed in the mid 1990’s when Troy Smith, CSFM and I stumbled into what we now call The Denver 10 football field mowing pattern out of necessity. I think it’s a better look, it fits the game better.

Here’s the thing limiting football field mowing patterns. The challenge in getting creative is that when you mow in a back-and-forth fashion, which is by far most efficient, the differing grains in the grass will tend to ‘squiggle” the white painted yard line of a football field when seen from the sideline angles, the main viewpoint for fans and TV audiences. An American football field is loaded with these white painted yard lines. As such, we tend to mow across the field in 5-yard blocks, and the lines are all mowed in one grain or another and so not look squiggled. The football field managers I know don’t seem to really care much about this limitation in presentation, they’re pretty much just glad when they have grass to mow!

In about 1994 or so, Troy and I received a new Toro 7-gang fairway mower to mow our 2 ½ field complex at the Denver Broncos training facility. We wanted a larger mower capacity as we were a 2 person crew and mowed 4-plus acres 3-4 times/week. The new mower was fantastic. We mowed more than twice the acres/hour, used less fuel and got a razor-clean cut. The only issue we had with the larger unit is a problem common to all larger mowers, the potential for the inside wheel to tear the turf a bit on the turnarounds. This was especially true on the tight turnarounds involved in the 5-yard mowing pattern and larger mowers. We decided to mow in 10 yard blocks and the much wider turnarounds solved the turf tearing immediately. Naturally, we started mowing the 10 yard blocks from goal line to 10, 10 to 20 and so on. We kind of liked the look, it was something different and most importantly it solved a newly created problem.

The Refinement.

By this time our fields had been in for several years with more or less year round heavy traffic and only overseeding as a repair option. This was a non-revenue field and good big-roll sod technology was in its infancy. Under this field management regime, we were getting a growing Poa annua problem in the fields. We tried everything to keep it at bay, even burning the patches with a propane torch, which didn’t work. You’d be surprised how much torch heat it takes to fully cook just the above ground parts of a P. annua patch.

One new strategy was using a relatively new and safe plant growth regulator called ‘Primo’ (trinexapac ethyl). P. annua had a higher sensitivity to Primo than the Kentucky bluegrass/Perennial ryegrass mix we were managing. The hypothesis was to take advantage of this sensitivity disparity using Primo combined with an aggressive Perennial ryegrass overseeding program and flip the population dynamics away from P. annua to Perennial ryegrass. To a certain extent, we had seen it work in converting golf course fairways. Eventually we found it didn’t eradicate P. annua, it just made it uglier and weaker from our experiences, at least with the earlier formulations.

We stayed with Primo in our management program because it made the grass stronger and more divot resistant, cut our mowing and associated fuel costs in half and even made our paint last longer and brighter into the late week practices during the season, or towards the end of a 5-day camp.

One day a few weeks after our first application, Troy noticed how we were not getting crisp edges on our numbers after painting because the edges of last weeks faded painted number sets didn’t line up perfectly with this week’s paint job. There was what we called “ghosting” in our numbers and cross-hashes. Turns out, the stiffer canopy from Primo was the culprit. We laid down the large plywood stencil over last weeks painted numbers and lined them up perfectly as usual, but now when we stepped onto the stencil to paint the number the stiffer grass canopy caused the entire stencil to shift about ¾ inch in the direction of the mower grain. It was really hard to correct for this and offset how we laid the stencils down to get things just right. I think it was Troy that came up with the idea of changing our 10 yard mowing pattern to do our 10-yard blocks on the 5’s, not the 10’s. This would put both numbers and arrows of a set in the same mower grain. This not only looked better we believed, it help a lot with ghosting issues.

So instead of one block going goal line to 10 and so on, we would now mow a 5-15 yard line block, 15-25 and so on. This would put both numbers and arrows of a set in the same mower grain. This not only looked better we believed, it help a lot with ghosting issues.

This also meant we would have to have two 5-yard mower blocks on the field somewhere to make it all add up. We chose the goal line to 5 yard line block for this. Our thinking was that when the line of scrimmage is inside the 5 yard line, this is when many teams call in the “Goal line” personnel packages. We used to always have practice periods simply called “Goal line” for both offense and defense to practice this very critical part of the game of football.

And like that, we had what we called “The 10 yard mowing pattern”, and since it was at an NFL practice facility, it was rarely seen on TV and by only a handful of visiting field managers.

The 10 yard mowing pattern goes national.

Fast forward to 2001 and the Broncos were now responsible for field management at the brand new stadium, now Empower Field at Mile High, in Denver. In the prior 30 years, we had played at the storied Mile High Stadium, owned and operated by the City of Denver. Denver Parks and Rec maintained the field. As the new stadium’s first field manager, I rolled out the 10 yard mowing pattern. With one game field rather than 2 ½ practice fields, we mowed with smaller triplex mowers and could have easily mowed a 5 yard pattern without any wheel-tear issues but I stayed with our larger blocks.

Now our novel mowing pattern was seen by television viewers, stadium fans and a wealth of media pieces. With a great team and strong backing from the club, we enjoyed a lot of success with the surface and won some awards. In 2005, the field won SFMA Field of the Year awards in both the professional football and professional soccer categories.

In 2010 I was talking to my turf team about this history. I challenged my team to come up with a gitchy name for the pattern that would give credit to its creation in Denver. My assistant field manager, Chris Hathaway came up with the name “The Denver 10”. Perfect! That was it.

Variations.

I’ve seen several variations, mostly having to do with where field managers place the two required 5 yard blocks. If memory serves, my friend Jeff Salmond is a phenomenal football field manager. He liked the Denver 10, but once put these required 5 yard blocs somewhere around the 40’s and jokingly called the pattern “The Oklahoma 10”. Nice try Jeff, love you brother. If my memory serves me right, I saw Iowa State do a 20 yard bloc version for a few games years ago. It looked pretty cool but when the TV camera zoomed in for the start of a play, you would often lose sight of any pattern.

Pro tips.

When first approaching a white, painted 5 yard line between two blocks, mow entirely over the line by a couple of inches. Then, you can mow just up to the painted line in the next block with the opposite grain. This way, you avoid two-tone painted yard lines and double mowing the painted line due to required swath overlap. This can only dull the paint in my opinion.

Don’t mow back and forth over the sidelines. The 10 yard (or 5 yard) block grains will squiggle your painted sidelines and show up on end zone views, either to a few fans or millions on TV. Stop short of the sideline as your first set of reels touch it. After all the blocks are mowed, you can come back and clean up the un-mowed spots from offset reels with a single swath along the length of the sideline and put your entire sideline in the same grain and tint, no squiggling.

Mowing the same pattern or grain in successive mowings, or “burning it in” is a great way to make your mowing pattern more vivid. However, you don’t want to ever keep mowing and graining the grass the same way over and over again. The grain can become too severe and affect the quality of your cut and appearance. Be particularly aware of this issue if you are using a Primo type (trinexapac ethyl) for increase strength and divot resistance. One simple solution to this issue is to simply reverse your mowing pattern periodically. We used to have two mowing patterns during the football season, “End zones east” or “End zones west”.

Back in 1995, Troy and I had no idea we were creating The Denver 10 or anything, we just were grinding details towards improved practice fields. And there is probably no connection to the fact that the Broncos went on to win back to back Super Bowl Championships after we perfected it. And who knows, maybe one day we’ll see this pattern used in a synthetic football field. That would be something.