Going Greener than Grass?

This is the only grass in our yard. It is cat grass. Cat Grass is for the sole purpose of gratifying our cats. They eat it everyday and because it is in a planter, they can have it all winter long. Maintaining our lawns in America is perhaps one of the largest wastes of space, resources and time. If we didn't have to mow our lawns...we wouldn't need lawn mowers. We could use the space to grow something greener and more useful to our lives. This cat grass is in a planter at the base of this little pine tree. So technically, we don't have any grass in our yard at all. This little pine also serves as our Christmas Tree..and this year our Easter Tree.
Consider how much waste of space, time, and money our "lawns" cost us each year. It could be greener, to get rid of our grass. In the next few years golf courses could very well become the only places grass is cost effective. Too bad most golf courses do not even bother to recycle their aluminum.