The idea of picking edibles at the park may not get your mouth watering, especially when you think about the reasons that dog owners take their companions to the park. But get off the manicured grass, and out to the edges, and you'll find wild edibles in abundance. Honestly, I never visit a park without spotting some good looking edibles. If you're worried about the pet droppings, or potential spraying in the park, then wash your harvest as soon as you get home. For even more insurance from pollution, wash the plants and then cook them. I would bet that there are fewer pesticides and chemicals on your foraged greens than the conventionally grown greens at the grocery store.