I will agree on the latter, although i still prefer just to teach when it's done, instaed of saying give it another week. But i cannot and will not agree with the first statement.
I have never grown organic. I spent a year flushing every plant because "that's what you have to do", and then spent 2 years not flushing anything. Every harvest was identical to the flushed. If there were salt buildups, who cares, because it did not effect my harvests in any noticable way whatsoever. My opinion of it is like having a home raid array on your computer for web browsing, it might be statistically faster, but the real world results are utterly indistinguishable from a single drive. Your use of the word "need" indicates a requirement, there is absolutely no requirement to flush no matter the nutes or growing medium.
My short answer to flushing, is that half do, and half dont, and the argument is continuously debated. If flushing made such a noticeable difference, there would be no argument or debate. So far as i am concerned, from my own experience, and many others, it is a myth. Yet another exmapple of people trying to turn growing weed into rocket science. There are 1001 tricks for growing "better weed" and the truth is you don't have to follow any of them to grow said better weed.
