Grun. Vert. Verde. Groen.

No matter what language you speak, that means "green."

For many, being green means helping to protect the planet from the negative effects of human beings with methods such as recycling, turning off lights, and using alternative energy. For investors, it can also mean investing in companies that do all this, and also boosting returns.

As we explored the green pastures last year for Earth Day, we looked at companies with Earth-friendly initiatives like Disney's (NYSE: DIS) environmental policy, Coca-Cola's (NYSE: KO) packaging plan, and Home Depot's (NYSE: HD) Eco Options program.

This year, in recognition of Earth Day, the day set aside to remind us to take better care of our planet, we at The Motley Fool are presenting you with a series of articles that point out ways in which you can be green, both personally and, possibly, with your investments.

Rich Duprey talks about the greener home, with homebuilders such as Toll Brothers using energy-efficient products in home construction. This ecological responsibility comes at a price, though. With the bursting of the home bubble, dollar concerns of today could trump green concerns of tomorrow.

Green's rising cost is something our other writers have picked up on, too. Maybe it's extra costs, maybe it's the belief that people will pay a premium to feel better. Whether it's one or both, companies do well to present a green front. Whole Foods (Nasdaq: WFMI) is one example that has done so while earning the nickname "Whole Paycheck." To be fair, though, the company is green in its own operations, being one of the largest purchasers of alternative energy.

In "Even Disposable Diapers Turn Green," Colleen Paulson points out how companies like Procter & Gamble (NYSE: PG) are trying to change perceptions about their own products, while also making them greener. And if you don't sell something green, go green anyway, as Bank of America (NYSE: BAC) has done with paperless statements.

With increasing interest in environmental policies, investing in green companies might do your portfolio some good. Rich Duprey returns with an article pointing out how our Motley Fool CAPS investor intelligence database can help separate potential winners from losers. One possible result of his search is agricultural giant Archer Daniels Midland (NYSE: ADM).

As you celebrate Earth Day, going green one way or another, take a few minutes to read through our Foolishly green stories. You'll feel greener with each passing article.

Bank of America is an Income Investor pick. Whole Foods and Disney were chosen by Stock Advisor. Coca-Cola and Home Depot are Inside Value recommendations. You can take a trial to any of these newsletters without spending any of that other green.

Fool editor Jim Mueller likes to see green, both in the woods outside his door and in his portfolio. He owns shares of Coca-Cola and Disney. The Fool's disclosure policy is evergreen.