Aquaponics. Taking all the advantages of hydroponics (i.e., using 90% less water, 100% less soil, decreasing time till harvest by 25-50%, and exponentially increasing the number of plants grown per square foot) but using fish waste as the plant nutrients.
This hand-built system utilized beautiful koi fish (my other hobby) and the naturally accruing bacteria that form on the volcanic rock / clay pebbles. The bacteria converted the ammonia-rich waste into nitrites to feed the plants, and, in turn, the plant’s root system cleaned and purified the water. This symbiotic system kept the fish tank crystal clear for over a year and exceptionally grew almost anything we placed into the bed.