Athletes have always torn up grass fields, especially during rainy, cold or dry spells. To fight back, installers have devised substructures that quickly drain excess water to keep soil firm and even pump in warm air to help roots thrive. Synthetics sprouted in the late 1960s after installation in the Houston Astrodome. The AstroTurf brand, named for the venue, remained synonymous with "artificial turf" for 30 years, even though players said it felt hard underfoot and complained of rug burns when they hit the deck. In the past decade a new generation of products from companies such as FieldTurf has overtaken the brand and been adopted widely. These products boast softer tufts and more consistent footing from "infills" of rubber granules or rubber and sand between the "grass" blades.

Debate continues over which surface is preferable. Last summer Purdue University renovated its football field with a new strain of Bermuda grass bred to withstand colder temperatures. "The new synthetics are great," admits Al Capitos, sports turf manager at the school, "but there's still nothing better than grass." Stadium managers acknowledge that most players prefer grass--if it is in pristine condition. But drought makes it hard, and rain makes it slick or uneven. In northern states, "all you need is a mud game after September when grass stops growing, and you've lost your field for the season," says Joe Frandina, head of stadium operations for the Buffalo Bills in Orchard Park, N.Y. His snowy facility has relied on synthetic turf for years.