When two college students in Oakland discovered they could grow mushrooms in used coffee grounds, they started a company to recycle the waste from local cafes.

Each morning the "Back To the Roots" team picks up 8,000 pounds of grounds in the back of a van for processing in their plant. They are on track this year to divert 3.5 million pounds of coffee grounds from landfills.

With Americans focused on growing local food, Back to the Roots gives families, even urban residents, an easy way to grow produce in their windows. Just spray with water, and watch them grow.

Their gourmet oyster mushroom kits are for sale at Whole Foods and 1500 retail stores nationwide.

(WATCH the Earth Day video from The Chew, featuring "Iron Chef" Michael Symon)