Green is good for the environment — but that doesn't necessarily mean that a green company is good for your portfolio's earnings and growth. Luckily, you can marry the two concepts, environmentally friendly and profitable, with some careful research and planning. Many traditional investors (i.e., those investing solely based on profit potential) used to turn their noses up at all forms of socially responsible investing, but they're looking much more closely at it now. Turns out that a lot of people care about the world as much as they care about the bottom line — and that translates to a boon for green investors. The more money that pours into green, the more profits will be taken by environmentally conscious investors.

On top of that, truly green corporations have as much profit motive as any other corporation. These companies are in business to make money, pure and simple. Sure, they're doing it in a way that helps the world, but the bottom line is the bottom line. And as the industry takes off, green companies are poised for substantial growth — which means capital gains for savvy investors.

Should you decide to dedicate your entire portfolio to green investing, you will still need to follow basic investing principles to ensure success. Assessing your current personal financial situation, time horizon, and risk tolerance comes first; this directs every investment decision you will eventually make. Next, you must determine the optimal asset allocation for your portfolio, allotting your investment dollars toward stocks, bonds, funds, and other assets. And within each allocation category, you want to make sure to diversify your holdings.

A successful green portfolio will hold some stock, some bonds, and some other investments, such as precious metals or real estate. You will need to monitor your green portfolio in the same way that you would a standard portfolio, weeding out losing investments and seeking out more profitable ones. By following these essential investing principles, your green portfolio will provide you with a nest egg that can make you both wealthy and proud that you've contributed to a cleaner, safer planet.