at one point in time there was no preserving food and it gets cold in the winter....people had to have been doing some form of indoor growing or another, like u said we didnt always have hps bulbs n shit but there were always house plants, just as we became smarter we made a better light for the times there could be no sun....thats just my guess tho....i am no textbookDoes anyone know anything about the history of indoor cultivation. I'm curious on how the indoor cultivation process came to using hps lights because I'm sure they weren't used from the beginning right?