Once my container grown plants in soil get big enough to handle full watering's, I typically do 20% runoff which is doing some mini-flushes along the way. I'll add that I use Advanced Nutrients pH Perfect nutes that are chelated to help balance the pH and nutrients preventing lockout. I have flushed before during the grow, but this is to flush a salt buildup to prevent toxicity in the soil. Some folks always flush before a harvest - but I cant seem to figure out why? Are minerals and nutrients that are inside the tissues of the plant likely to be pulled out of the plant by a flush? And why would we want to rob the plant of its nutrients immediately before harvest when adding bud weight is most critical. Seems the plant needs nutes the most at this point. I have done with great success: Water the plant AND feed, close up tent and do a total lights off for 36-48 hours, then take plant out of tent and harvest. I have done this method for some time now, and when cured carefully, I get the best, smoothest smoke with no harshness as supposedly is the reason to flush at harvest to begin with. BUT, I am not a know-it-all and very open to suggestions. If I'm missing something, please fill me in. I really want to learn if there is something I need to change for the better. Thanks.