When it’s cold outside, many folks snuggle into a warm blanket. The same can be said of the grass at Columbus’s MAPFRE Stadium, home to Sunday’s sold-out MLS Cup final between the Crew and the Portland Timbers.

Weston Appelfeller, director of grounds for the Crew and caretaker of the Sports Turf Managers Association’s 2015 “Field of the Year” for professional soccer, tells SI.com that a grow blanket covering every inch of the Kentucky bluegrass and perennial ryegrass turf keeps temperatures warmer and his turf growing, even into December.

“It is definitely a different year for us,” he says. “Normally we shut down by this point and have the field ready for winter. Now we are trying to keep the field warmer than the outside temperature.”

The grow blanket—which still allows sunlight to hit the grass—ups the field temperature about seven degrees compared to outside, so coupled with some non-freezing weather, Appelfeller says the turf has remained in a growing state, an extremely rare occurrence for Columbus in December.

The groundscrew plans to keep the blanket in place until Thursday, providing a total of about 10 days of blanket time, when they’ll pull it off and mow in two different directions—east-west and north-south—to set in a “standard soccer” pattern. The Crew’s groundskeepers will roll the field and fertilize it one last time before mowing again on Friday, leveling the grass to 15/16ths of an inch before painting the white lines and setting up the goals.

The teams train on the field Saturday, so Appelfeller wants it in true game-like conditions for the entire weekend.

Appelfeller worked for the Crew for two years in 2006 and 2007 when the field was only Kentucky Bluegrass before spending a few years with the Boston Red Sox and a year with the Philadelphia Union before rejoining the Crew in 2012. He says they need the MAPFRE Stadium field in the best condition possible for Sunday in order to be ready for an early spring MLS start and a U.S. men’s national team World Cup qualifier in March.

“The worry we have as groundskeepers,” he says, “is any damage we have now we are likely to still have in the spring. If we have a divot now, that divot will probably still be there for the first game. We want the field to be as strong as possible for this weekend so we have less damage we are trying to fix in the spring before the U.S. game.”

For a field that has won the Sports Turf Managers Association award three times in the last five years, MAPFRE Stadium's turf requires top-level caring, especially with December and early spring events, Appelfeller says. But those are the events that make it all worth the effort, so when it gets a bit cold outside, even the MAPFRE Stadium field has a blanket to keep it cozy.

Tim Newcomb covers stadiums, sneakers and technology for Sports Illustrated. Follow him on Twitter at @tdnewcomb.