Here is an article describing a method of producing vegetation and fish in a symbiotic relationship all without dirt. Could this, as the title of the article suggests, revolutionize the way we eat?
Aquaponics is a method of combined fish and vegetable farming that requires no soil. The farmer cultivates freshwater fish (aquaculture) and plants (hydroponics) in a recirculating water system that exchanges nutrients between the two. Wastewater from the fish serves as organic fertilizer for the plants, while the plants clean the water of fish feces and urine. The net result: a 90 percent reduction in freshwater use compared with conventional fish farming, and a significant reduction in added nutrients such as fossil fertilizers. The system can be run without pesticides and, because the fish environment is spacious and clean, without antibiotics.
At the very least this might open up a new avenue for producing food in cities with limited farmland but plenty of space on rooftops.
h/t Tyler Stockton