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Grow Q&A: Do Organic Pot Plants Need To Be Flushed?

Photo by Dread Smokes Weed

Dear Dan, I have a question about flushing. I realize that when feeding synthetic chemical nutrients you must flush the salts, however, when growing organically, as far as flushing “nutes” from the soil, I’m really struggling to understand the point of this.

When growing organically, what would you be trying to “flush”? Microbes? I am basically running a fairly hot soil and feeding compost tea. Thanks for your input. – Kushyman

Dear Kushyman,

You should always flush your plants whether you grow using synthetic nutrients or organic ones. Both methods feed your plants with chemical elements, some of which need to be removed using the flushing process in order for your buds to burn properly, to a clean white ash. Organic nutrients derive these chemical elements from natural sources while synthetic plant foods are formulated in a laboratory from inert chemicals. Both build up in your plants and medium over the course of your grow cycle and the flushing process removes them.

For the last week or two of the flowering stage, use plain pH-balanced water and pour it through your medium at 3 times the volume of your containers (ie. 15 gallons of water for a 5-gallon bucket). After a few flushings, start testing the water that pours out from the container and you’ll see the ppm’s (parts-per-million) of your solution starting to go down. This is a good sign.  Your fan leaves will also begin to fade in color but don’t be alarmed. This is another indication that your flush has worked.

Have a grow question? Ask away at

Don’t miss our previous Grow Q&A: I Wanna Grow Weed, But My Parents Hate It



  1. Avatar

    John Dough

    July 27, 2016 at 2:51 am

    First I would say that you do not need to flush your plants no matter what you are using. I use straight hydro, ebb and flow using bucket within a bucket. I have not only never flushed but not a single time heard a complaint about how it burned. I think the person writing this article needs to do some research first before posting such nonsense especially for such a respected magazine. If this was a legit article the writer would have done test grows both ways and had them tested for various “built up nutrients”.

  2. Avatar


    August 1, 2016 at 9:31 am

    When growing organically PROPERLY, you stop using nutrients during the last few weeks, so the plant can use up all the remaining nutrients in the soil, therefore there is NO reason to flush the plants. Flushing is only necessary if you use too much of the nutrients, and don’t stop fertilizing until too late. If you are going to write articles on growing cannabis you should learn about it first..!

  3. Avatar


    September 4, 2016 at 7:29 pm


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