What makes a detergent "green"?
You can't really check the label for this answer since laundry detergents aren't regulated by a government agency that requires them to list ingredients. But for the most part, if a detergent claims to be green, it's because of the following criteria:

It contains surfactants derived from coconut, soy, or palm oils. (FYI: "Surfactant" is just a fancy word for soap.) Unlike petroleum-based surfactants that come from crude oil, biodegradable plant-derived surfactants come from renewable resources. Scientists have figured out how to get an effective clean from plant-based soaps -- so you're not sacrificing cleaning power to protect the earth.

It's dye-free. Dyes can irritate skin -- sometimes more than fragrance, says Gwen Whiting, cofounder of The Laundress, a green brand. Unlike most regular detergents, which are dyed blue or green, environmentally green detergents are usually clear or milky white.

It uses a bleach alternative instead of chlorine bleach. Green detergents rely on an oxygen bleach, optical brighteners, or baking soda as a chlorine bleach alternative.

Look for green detergent brands like Mrs. Meyer's Clean Day, Sun & Earth, and Arm & Hammer Essentials, which are available at grocery and specialty chains for about the same price as premium mass brands.

Can I use fabric softener with everything?
Nope. Skip fabric softener when washing towels, athletic wear, and baby clothes. Most liquid fabric softeners use tallow, an animal fat by-product, as a softening agent, while green brands use plant-derived soybean or vegetable oils -- either way, the greasy base will interfere with absorbency and flame retardance of the items mentioned above. On everything else, go ahead and use it! Softener leaves clothes feeling soft and fluffy and makes ironing easier, as it cancels out the static charge on the fabric's surface. But whether you prefer liquid or dryer sheets, use a softener only every few washes -- when used every time, it can build up and cause a dingy appearance, according to Martha Stewart's Homekeeping Handbook.