A lawn never subjected to chemicals can exhibit a broad and attractive range of plants, here featuring purple and white wild violets (and, in the middle distance, an area of meadow hyacinths that will soon bloom in purple and white):
Finding a toad is also a good sign, as amphibians like toads and salamanders are very sensitive to chemical poisoning. From the base of a tree just off the above photo, this is a well-camouflaged Eastern American toad:
Toads breed in water and that one must have hopped safely across 500 feet and 2 streets to get here, some time in the past 30 years (their life span, under good circumstances.
Here is a salamander from about 25 feet away in the same back yard, found under a flat stone (which, here pictured on the left side, of course was carefully replaced so as not to disturb the wildlife, which if you look carefully includes 2 snails near the salamander’s tail). Although only about an inch long, it must be a northern slimy salamander (which grows up to 8 inches long!) lives in just this environment and breeds on land.