Restore Eden - Domesticate Terra! :)
As you gather this spring, keep an eye out for healthy patches of wild edibles. Watch for them to go to seed, and gather the seed. Come fall, go to parks, abandoned lots, etc, and toss the seed along creek beds or shores of ponds. You can increase the amount of food being produced on these properties without risking "invasive species" issues if you use native, wild edible seeds.
This is the article that got my posting privileges revoked: