In 1956 English scientist Salmm-Hormer found a method where sand could replace soil. Four years later German botanists Sachs and Knop grew plants in water, and the effect of these experiments set other scientists thinking that if plant nutrients could be made to reproduce, then soil could be dispensed with.
一九五六年，科學家 Salm-Horsmar 首先發難，找出用砂來代替土的簡易栽培法；相隔四年，德國人 Sachs 與 Knop 繼而發現，將營養成分溶在水中，植物仍可正常的生長。