CHICAGO -- Chicago Park District general superintendent and CEO Mike Kelly said Wednesday the park district had done research to improve Soldier Field's sod and he doesn't expect the Chicago Bears to have any problems with the playing surface this season.

The quality of the field, which is also used for high school football games, concerts and more, has been a concern for football players in the past. Many players, including several on the Bears, have said the field is among the worst in the NFL, especially when the weather gets severe.

A year ago, the Bears had to cancel their Family Fest because the playing surface was deemed unsafe.

"The irony last year when we had the family night even with the sod, that sod actually was the longest-performing sod we ever had in my 10 years at the park district," said Kelly, who announced Wednesday that Soldier Field would host a college hockey doubleheader on Feb. 17, 2013. "It really depends on the weather. So if you get a lot of rain, and they're playing on the rain, it gets chewed up faster. We've been working a lot with experts from out East on the way we grow grass here. I think we've made a lot of changes for better."

Kelly said the type of sod they use for Soldier Field is the key to the improvement.

"The single biggest thing we learned is Illinois soil is very clay based, and the best natural grass grown in the world is sand based," Kelly said. "There's no sand-based sod farms in Illinois, so we've really had to sort of configure. It's a little bit of an art and a little bit of a science on trying to improve the grass out here. As I tell any reporter who asks me, I know more about sod now than I ever certainly thought I would. Soldier Field will perform nice for the (hockey) game, and it will perform top notch for the Bears."

Kelly also expected this year's Bears' Family Fest to go off without a hitch on Aug. 3.

"(The field) will be fine," Kelly said. "It will be perform. It will perform well. We argue still we're the best northern-climate stadium certainly in American that can perform, grow grass as the best you can in October, November, December."