What do I do with an overgrown garden?

I have never had a garden before but bought a house and have a 20x20 patch of garden which is over grown with milkweed, dill, fennel, baby maple trees, and some random not so pretty weeds. I am planning on pulling the herbs and potting the baby trees to sell at farmer's market and just plain pulling the weeds. Question is what low maintenance things do I plant in place of the junk? It's June so I kinda missed spring, and I can't do tomatoes because the owners said they had tomatoes infected with fungus last year. I have to give it another year for the fungus to leave the soil.