Flushing ??

How important is flushing if one does not use any chemicals at all. Simply FFOF tap water and a little molasas. I've been growing for over a year, only bag seed, but i recently ordered some ICE seeds from nirvana, and it is now harvest time. I've included a few pics as well

i take it from a lack of responses that no one knows for sure?

You cant really flush dirt! but I give my ladies nothing but pure water for the last two weeks.