pretty much .... all of my autos have been grown in light soil- perlite- bit of bat shit - 3 gal pots
i used a little grow and a little bloom with my first (green o'matics) ...and got burns... so with my second (critical jack) just rain water from start to finish, showed lack of P during mid-late flower (it looked like crap but had a decent yeild. over 1.4 oz bone dry)... but tasted GREAT and nearly ripped my head off
so yeah its more then possible to do it without nutes
i've now decided to start with a 1/4 strength bloom for the last 3 weeks of flower with my Pineapple Express (auto) as its a hungry beast and was showing lack of P, and i'd like to hang on to a few fan leaves this time! hahaha