Q: What's white with red seams and green all over?

A: Baseball on Earth Day.

Major League clubs are taking a green approach to Wednesday's games, be it by setting an example with composting on a huge scale or by enacting programs to make their homes -- their baseball homes -- certifiably green.

Few places can match the Emerald City for its green attitude -- after all, it was at a September 1969 conference in Seattle that this date was proposed as Earth Day by U.S. Senator Gaylord Nelson of Wisconsin.

The Mariners have been celebrating Earth Day for several years, including last year's Carbon Neutral day in which they offset carbon dioxide (CO2) pollution generated staging the game. This year, they're hoping to put up a zero that might not show up on the scoreboard but will be a big win: zero waste.

Following the City of Seattle's Zero Waste initiative, the Mariners will be will striving to reduce to an absolute minimum the amount of garbage going into the waste stream. As amazing as that sounds for anyone who ever kicked through wrappers and cups at a ballpark, that's the goal.

How can they do that? In a word: compost.

The Mariners will join with local firm Cedar Grove Composting to shift almost all food service items -- plates, bowls, utensils, right down to the "boat" for your hot dog and even straws -- to compostable materials. Also, Ciscoe Morris, described by the Mariners as a Master Gardener and "composter extraordinaire," will throw out the ceremonial first pitch.

After the game, a team of volunteers will scour the ballpark seating on a search for recyclable and compostable materials left behind. Of course, fans will be encouraged to help out as they eat and drink along with the baseball action.

As one of many teams in Major League Baseball with such efforts, the Mariners' recycled 396 tons of material in 2008, composted 168 tons of food waste the last two years and sell organic products in their team store.

Obviously, the Mariners are not alone in their projects as Major League Baseball continues its Team Greening Program and Earth Day is being celebrated around the country in various ways, including:

Astros: The team's Play Green campaign will celebrate Earth Day by participating in a one-day build of an energy-efficient Habitat for Humanity home, with outfielder Hunter Pence and broadcasters Bill Brown and Jim Deshaies joining the project. The game against the Dodgers will include green caps, and the first 10,000 fans will receive a Play Green baseball cap. The Astros already have been participating in a Home Runs for Trees program which plants a tree for every Astros homer and a number of other green efforts at Minute Maid Park.

Pirates: In conjunction with their "Let's Go Bucs. Let's Go Green." campaign, the Pirates will host several events that will take place throughout the day to highlight resource conservation, integration of greening initiatives and the promotion of green practices throughout the Pittsburgh community. In association with Hess Corporation, PNC Park will use 100 percent renewable energy on Earth Day -- by matching every dollar spent on electricity with one spent on natural energy resource development. Also, all fans who choose to ride their bicycle to the game will receive Earth Day discounts as well.

D-backs: The club announced Tuesday it has hired a consulting firm to facilitate achieving Leadership in Energy and Environmental Design (LEED) certification for Chase Field prior to hosting the Major League Baseball All-Star Game in 2011, which would make Chase Field the first such ballpark to host an All-Star Game.

Giants: Partnering with Esurance, the Giants will give away a reusable, fabric grocery bag to the first 20,000 fans and and throughout the game remind fans what they can do to green their lives. AT&T Park is working to become LEED certified, and already is home to the first solar system at a MLB ballpark as well as an aggressive recycling and composting program.

Angels: Every fan in attendance Wednesday will receive an Angels banner made of recycled materials, and environmentally responsible products and services will be showcased. Also, fans who bring in any recyclable item will receive a free gift such as Angels tickets, movie passes, coupons or other sponsor-donated items.

Nationals: The club announced a special ticket promotion for Earth Day home game, giving all fans who present their metro farecard or SmarTrip card at the Nationals Park box offices $3 off any ticket priced at $10 or more. Nationals Park is the only LEED-certified outdoor sports arena in the country, with a 6,300-square-foot green roof over the left-field concession stand and numerous other green efforts.

Red Sox: The Red Sox are working with Waste Management to hold a one-day collection of used compact fluorescent light (CFL) bulbs at all Fenway Park gates. Waste Management will transport the collected CFLs to its facility to dispose the bulbs in a safe and proper manner.

Reds: Reds left fielder and resident environmentalist Chris Dickerson had planned a subtle way to mark Earth Day on Wednesday. He had his glove manufacturer make him a special green and gray colored mitt. He's been using bats with green labels since the season started.