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Flushing plants

Plants that are grown synthetically are usually flushed with clear water for 2wks prior to the end of their grow cycle, is there a need to flush organically grown plants? Why or why not?

When I say organically grown, I mean ameneded soil that receives no bottled nutrients. I understand that all the nutrients are in the soil already, but there has been debate amongst our grown team about a flush and whether or not it’s needed or would be totally useless or cause more harm than good.

What are you thoughts? Would appreciate any articles to back up opinions.



The aim of flushing is to let the plant use up all its residual nutrients and put it to the final flowering , as well as clearing out excess salts etc. It can be used in an organic grow, although is not quite as necessary as in a synthetic situation. How are you growing the plants? In soil in pots indoors? If the plants are grown in only an amended soil - do you add any nutrients to the water? What are you amending the soil with? Do you use beneficial fungi and bacteria? There are a lot of variables to consider as different elements of the soil ecosystem will interact differently.

The flushing process clears the excess nitrates out of the plant, which lead to a black ash and poor burning - I flush and dry stress my plants in the last 2 weeks to force them to use all the excess nutrients and increase trichome and thc production (a natural defense mechanism).


The soil in in fabric pots indoors, amended with compost, earth worm castings,etc…lots of stuff. They are top dressed occasionally throughout the cycle, mulched with straw and a cover crop as well. They receive teas, clear water, and sometimes the grower add things like aloe or coconut water to the mix, etc etc --but not bottled nutes… when they are up-potted mycorrhizae is added. I can’t give too many specifics, as I am in charge of our mom room and don’t really get the chance to work in the soil dept. However, we do reuse the soil in the cloth pots, at the end of each grow cycle the stumps are cut our and new plants are put in. (Which goes against the horticultural practices I was taught, but organics wasn’t a part of my education to be honest, this is why I’m posting on the topic.)

With all that being said, if we were to “flush” the soil, could it be detrimental to the “health” of our living soil that is going to be reused over and over?


Well it sounds like you are working on a really healthy soil food web. Depending on how late you give the teas - but really - just watering them for the last week or two won’t hurt them or the soil food web. As long as it is balanced - if you wanted you could collected the ‘flushed’ water and test for nutrients etc and reuse it.


You could also look at potentially adding biochar into your soil as it would enhance the bacteria and increase soil resilience. If you worry about flushing destroying your soil - look at nature - the best soils in the world get naturally rained on (flushed) all the time - with a well balance soil-food-web all the bacteria, fungi, micro and macro organisms all work together to extract and integrate nutrients into the cycle.

Leaving the plant roots to rot increases organic matter, feeds bacteria, worms, and other organisms, and creating little channels deep into the soil (in a true no-till system) that allows water to penetrate and soak in further and deeper into the soil interface. Growing in pots isn’t quite the same but your methodology is sound.