To Flush or not to flush? That is today's question

US: New research shows flushing plants before harvest may be unnecessary

The results of a new research trial released this month show that flushing plants before harvest may not improve the quality of cannabis flower. The results seem to contradict the commonly held belief that flushing plants improves the taste and burnability of dried cannabis flower.

Under common, although not universal, cultivation practices, cannabis growers stop fertilizing their plants one to two weeks before harvest in an effort to improve the quality of their finished product.

“Flushing is important because it removes excess nutrients that are leftover within the plant,” explains High Times senior cultivation editor Danny Danko. “So it helps with the burnability of the flower by leeching out excess salts and nutrients.”

But in the trial conducted by RX Green Technologies, a manufacturer of cannabis nutrients and other cultivation products, researchers determined that those participating in a blind test tended to prefer cannabis flower that had not been flushed before harvest.

To conduct the trial, growers at the RX Green Technologies research and development facility in Colorado cultivated cannabis plants of the strain Cherry Diesel in a coco-based medium. During growth, the plants were fertilized with the company’s brand of nutrients. Four groups of 12 plants each were subjected to different flush times as harvest approached. Each group of plants was flushed for either zero, seven, 10, or 14 days.




Thanks for sharing @Stephen
I am happy to see they are continuing this type of research.


Allgrowers I would love to hear from you on this topic!
Anyone who has tried flush and no flush test please weigh in your personal preferences for people like me who don’t smoke.
Thanks in advance! I appreciate you!


Sorry Stephen I would be more interested in seeing some long term studies regarding the effects of nutes being consumed my smoking by not flushing as opposed to flushing. How harmful can they be if not flushed right? Sorry Stephen too many years in school…


If we are consuming this plant for medical purposes, at least I am, then isn’t the goal to make as pure as possible?


Flush makes all the sense in the world to me…


I for one, have always found plants that were flushed, burned better and slower, was smoother, and didn’t get the hacking coughing that comes along with plants that weren’t flushed, or weren’t flushed properly! Just my experience :+1::v:


Those are all very big reasons to flush! As always you rock!


Still with u sister! Keep on keeping on :+1::v:Still keepin an eye on you!


Love the info! I was just wondering about the flushing stage. I think I will shorten mine to 5 days. I’m growing the same strain back to back to next round l will do a full flush!

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Flush or not to flush?

((#Interesting)): :nerd_face:



It’d be interesting to see this trial done with a wider set of feed and routines and including more analysis into the final composition of the product (estimate of mineral content pre/post burn) and the byproducts (tar/toxin content produced from combustion).

My suspicion is that if the plant is able to use all of the nutrients that it is given then there won’t be anything to flush, as well as the opposite - if there is an overabundance of nutrient(s) then something is present to be flushed. This seems to correlate with what I’ve seen but is purely anecdotal.