St. Louis has a big Earth Day Festival each year, but we missed it today. The weather was just too nice not to spend it in our own yard. Doug raked acorns and de-thatched* the front yard, while I started on a wine bottle border for one of our garden beds. I managed to get all of my food plants fed and mulched today as well, so I feel I've accomplished something.
In early spring, just before the first time you mow, you may notice a lot of little purple violets in your yard. It blows my mind that so many people think of them as weeds: I think they're beautiful. The leaves and flowers are also edible (provided you do not use synthetic fertilizers, pesticides, or herbicides on your lawn). They taste mild, like a lettuce, and they make for a beautiful salad!
As with most plants, violets seem to look fresher if you pick them in the morning. If you're not going to eat them right away, place them in a bowl and cover with cold water. They'll keep that way for hours, maybe longer but I've never tried. I use a "Salad Spinner" to dry them before use. That's all the prep you need: even the flower stems are edible.
* When you've been organic for awhile, you shouln't have to de-thatch your lawn. However, we're in transition since we have only been here 18 months, and the lawn has suffered from years of high fertilization and short mowing: a perfect recipe for thatch.