I grow organically and don't flush, I just stop giving nutes when I water for a while. You don't need to flush when grown properly. Flushing is illogical in that we dot flush anything else, all those nasty "nutes" are in t he tomatoes and broccoli still. But that all is aside from the fact that most of these "nasty nutes" are immobile within the plant anyways. The nutes are not defying gravity and capillary action to go back DOWN the stock and back OUT of the roots. It's just a misconception that fuels the need for flushing. Proper drying and curing is all that is needed. Damn I get suckered into this conversation every time!