An Earth Box is effectively a hybrid of hydro and living soil: nutrients ride on top where feeder roots and worms work, while clean water lives in the reservoir below where water roots drink unforced.
Jeremy contrasts this with a normal living soil bed where watering through a top-dress forces plants to drink nutrient-laden runoff. In an Earth Box the water and nutrient zones are physically separated so the plant controls uptake.
Discussed in: Ep 012