If you like aquaponics, then take a look at Goliad Farms. He raises greenhouses full of tropical fish, relying entirely on plants to remove ammonium from the wa

If you like aquaponics, then take a look at Goliad Farms. He raises greenhouses full of tropical fish, relying entirely on plants to remove ammonium from the water. And yeah, that root zone microbiome is complex, though somewhat different in containers than in nature. In soil-like potting mix, you're generally guaranteed to have nitrifying bacteria, so ammonium fertilizers are still generally safe to use. (Ammonium can easily become toxic to plants; but soil bacteria oxidize it to nitrate, which plants tolerate in higher concentrations.) Stuff like sulfur to amend soil pH doesn't necessarily work in containers though, since you don't necessarily get the bacteria that oxidize that to sulfuric acid. Nitrogen-fixing bacteria for legumes may also not be present unless deliberately inoculated. The plants would die without that microbiome in nature, but with human help it's not mandatory. Many hydroponic methods run with a root zone that's as sterile as possible, and the only major change required is to supply most (~90%) of the nitrogen as nitrate.