I know a lot of people say that it's important to flush before harvesting, but through my experiences I found it isn't necessary. Now this is simply what I have found from trying it both ways. I have only been growing for 5 or six years now, but the one time I did flush my plant before harvesting, it seemed like the plant suffered more than anything. The leaves all started turning light green and dying. Almost like the plant was eating itself to feed itself. The way I see it, the MOST IMPORTANT TIME to feed your plant is the last week or so when it is finishing up and it's looking for those extra nutrients. What I've learned is that if you dry it right, and CURE the buds for a good month, that's what makes the weed smooth and enjoyable. Just my opinion. What you can try though is this. If you are gonna flush a week before harvesting, cut one of the more mature buds off before you do it. Dry it slowly and cure it, and then compare it to the rest that you flushed. I'm pretty certain you won't see much of a difference if any at all. Once again, just my opinion.