[Dr. Sivana]

...because grass growing in June and July is the same as September through December...

There was NFL football played in December in cold weather stadiums before Astro Turf was even invented. You don't need the grass to grow, just to hold the ground together. The main problem is domed stadiums.

[T.B. Yoits]

There was NFL football played in December in cold weather stadiums before Astro Turf was even invented. You don't need the grass to grow, just to hold the ground together. The main problem is domed stadiums.

True but only if it freezes once and stays frozen. Then it's as hard as concrete and leads to injuries. There are ridges and cleat prints frozen in place until the spring thaw. There's no way to repair it if it's too torn up.

Games such as the December 26th 1977 NFC Playoff "Mud Bowl" in Minneapolis helped push the league to switch the Astro Turf. And they're not going back either; sweat, blood, and spit in the mud are completely unsanitary.

[woodbutcher1963]

The domed stadium in Phoenix has a real grass field that goes in and out on a track.
It goes out to grow in the sun and gets irritated.
Then cut and rolled back in to play the game inside.
Especially when outside is over 100 degrees.

[discostu]

Sunlamps and sprinklers. If guys can grow weed in their closet and NFL can grow grass in a dome.