Ah!!! you just solved the mystery of why years back I had such an amazing patio garden. It was a veritable jungle of giant sunflowers and morning glories, and scented geraniums, etc. It was the no-cost baskets we picked up from outside the chinese grocers. They had been used to store crabs...there were some bits and pieces I left in.
there was nothing magic in the soil I used, but that garden was a magnet for the neighborhood.
I grow a lot of heavenly blue morning glories (on my long patio/veranda: not the same place as the old garden)and some assorted mints and sweetgrass. Would love to have an
earth-level garden, or even a rooftop garden. My mother used to grow astounding amounts of vegetables in raised wooden boxes in our backyard....