To flush or not to flush....a science review

With all the talk of flushing etc, I found this scientific review, not a long read but changes my outlook now:


Just looking at the summary in that article there @Ocean and I think I’m really leaning towards not flushing at the end of my first grow and just making sure I cure properly. Do you flush at the end of grow or not please?


Let me share a little story with you. Years ago, in the early 80’s, I worked at Rutgers University on their vegetable research farm. There was this hippie looking professor that would come out to the farm periodically. I became friendly with him, and discovered that he grew cannabis for his home use. I learned a lot from him. I asked him about flushing, and he laughed, and said “that’s not how plants work. That is an old stoner myth. If you don’t believe me, take a any plant and water it continually with food dye. The leaves will turn the color of the dye. Then u can flush that plant with all the water in Lake Michigan, and the color will not be flushed out of the plant”. He gave me this advice…give them a lot of light, fertilize moderately, and dry and cure it right… this guy was a PhD in plant pathology, and I follow his advice to this day.


See this makes perfect sense to me. Plus all the other reading I’ve done in the past few days says you can’t pull nutes back out of the cells of the buds that have already grown up into them. Thanks @Otis :purple_heart:


This isn’t the study I read but it’s very similar. The one I dove into was a blind taste test
of flushed buds and non flushed buds and the study showed people liked the non flushed
buds far better than the flushed buds. I flushed my first grow but won’t be flushing my second grow. Period, end of story.

Less work for better tasting buds, hell yes, I’m all in.
Now to just get the curing process right.


No, I will not be flushing anymore. Tons of reason but besides the article and what others have already stated…if I flush them the plant starts dying and if my harvest “guess” is off then it will be too late, if I continue food for them then I can harvest whenever I see them how I want them without the worry of having to wait an additional week (if they are not ready). Hope this makes sense as it does in my head lol


Thanks both, yeah this all makes much more sense to me than the idea of shock starving them of the nutes they’ve been used to


This study was eye opening for me…Thank you @Ocean for adding some science to the discussion.
I saw and read this post/study when you first posted it, sorry for the delayed reply.


Interesting. I never used to flush before harvest til I started using Advanced Nutrients 6 years ago, which has a 2 week flush at the end of flowering in their nutrient schedule/calculator. I would think if the company that makes the nutes you are using says to flush than you’d be better off flushing.

But in the end does it really matter if you flush or not? Seems not, as the study says THC, terpenes and flower weight were not affected either way and the only real benefit was more testers on the “expert panel” thought the no flush had a better taste, which is more subjective rather than objective. Would love to know who these experts were as I’ve done taste tests with my “expert panel” and the majority preferred the smoothness of the flushed buds while a few preferred the more loud flavor of the unflushed bud.

Will have to test again on my next clone run (flush some and not flush one of them) and blind test my expert panel.

In the end all that matters is which way do YOU (the grower) prefer it. When the best selling beer in America is Bud Light (yuck) - it clearly shows that there is no accounting for taste.


@Hellraiser. LOL Only Coors light in this house but I did home brew for years!


Also, green leaf plants at harvest bore me, see how the unflushed one (d) still has green leaves at harvest - boring.

You won’t get plants as pretty as this without flushing/leaching at the end, which also really helps bring out the phenotype expressions as well.


Nice topic, but in the wrong categoty. No grow related topics allowed in the Grren room. this is our social area. I moved it to the proper category; GROWfaqs