I've read in many posts about flushing? Not totally sure if i understand how or why to do this. Is it so it the buds will smoke better-less harsh? It sounds like its done the last few weeks of flowering to get nutrient build up out of the roots. Can someone please explain how-when to do so or why?

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When I die, I want to go peacefully like my Grandfather did, in his sleep -- not screaming, like the passengers in his car