Flushing coir

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Hello farmers!

I'd like to maybe start this thread & develop it into a sticky as this topic seems to come up over & over re the coir... some aren't even aware that this just might be a big deal.

There are many threads & posts over the last few years regarding this very topic across varying sites. And perhaps there is no one true answer, but I'd like to offer my insights & possible get others to post their experiences. At least this info (& varying points of views) will be easily accessed by those considering the coir. This is my hope w this thread...

Okay, I believe in preflushing/treating one's coir prior to planting. My primary reason for this stemmed from the observation of two simple facts:
1. The initial run-off from all manufacturers of coir that I have used (most every brand) has a ppm count ranging from 700~2000+ (off my scale/meter).
2. Plants that start in preflushed/treated coir always did "better"~ healthier & more vigorous & no def issues.

This, however, flew in the face of several major threads out there on the topic... many, many say you do NOT need to flush your coir... it's great right out of the bag. My gut feeling is that a true side-by-side, over a few runs was never actually conducted, nor any detailed measurements of run-off.

Here's are my contentions based on a somewhat limited understanding of how coir functions as a medium:
1. Coconut trees store a vast quantity of Na/K & other cations during their natural growing processes/environment.
2. Most all hydro coirs are aged & "naturally" flushed... rain water running through open piles of unprocessed coir sitting outside for up to 2 years.
3. Once we get it, it still has quantities of unknown elements & compounds residing within as no formal flushing was ever conducted (atami/canna treat though).
4. This is evidenced by the initial ppm readings.
5. Nothing that is still inside the coir is likely what you would choose to put in there by means of solution feeding.

I haven't done a chemical analysis of the varying coir samples available to us. Perhaps this would be an interesting project to conduct...? However, everything stated thus far seems pretty straight forward & reasonable.

So, if you planted straight into untreated/flushed coir, there are anywhere from 700~2000+ppms of unknown elements & compounds that will influence how your plants grow. Run a side-by-side, you will see the difference. I do not have this set-up now, but in the upcoming months, will start some cuttings & post pics to see the differences.

When running the coir in a rez system, all of this junk is perpetually recirculated & refed to the plants. It will very likely hinder healthy growth... this is what I have noticed, without any doubt.

When draining to waste, it isn't that big of a deal because w each feed, some of the initial junk is getting flushed out w the run-off. By the end of 2 weeks, it is pretty much completely gone.

That's my concern in a nutshell & the reasonings therefor. I really believe in pretreating/flushing & offer this to assist others by preempting such problems.

Here's the flush/treatment that I employ:
1. Hydrate w tap as this contains Ca (I use compressed coir btw)
2. Run a lot of tap through the coir
- initially pith & a brown staining will occur w the run-off
- this will go clear rather quickly
- run the tap through for another minute or two, just in case
3. Mix solution w 4ml/gal CalMag+ & pH adjust to 6.3~6.5
- this will replenish the cation balance w Ca & Mg as you essentially flushed it all out just before
- as coir has a high CEC quality (cation exchange capacity), unless you recharge w the cations, it will be less available to the plant until the buffer is achieved w/in the coir
- an aside on pH... usually notice compressed coir comes in very low (4.6~5.1) & that bags can do the same thing, though w a wider range included higher values
- usually run a higher pH (6.3) while this initially balances out... may take me 3-7 days to accomplish. Just a heads up.
4. Plant your babies & top feed w your normal nute regiment, along w 1ml CalMag+ per gal for the veg period.
- this is to ensure CEC balance & full availability to the plants
- by flower, this balance is fully achieved & CM+ is not needed any longer

There are variations I employ, but this is the real deal... it works. Like I said, will try to post a side-by-side as it is workable for me to do.

Hope this helps & would like to even see contrasting opinions & the reasons therefor.

Thank you everyone! Greenest of vibes ;-)


Oddly enough, the Canna (bagged) capped out my ppm meter... 2000+. Nice texture & consistency + ran well d2w. Measured this off of several bags, several times throughout the year. pH always came in 4.6~5.1, initially... though would stabilize where ever the mix was... eventually. Good stuff, no doubt. Peace brother & ty SB ;-)


Hi all, GroHi, haveing used bagged and compressed coco coir, I prefer compressed. I put a brick in a 5 gal. bucket of hot tapwater, and let it sit 24 hrs. I then drain and sqeeze all the water out possible with my hands. Then if you like you can add nutes or what ever you like to your rinsed coco. This has worked well for me. :) peace


I'm glad there is some interest in this topic! :-)

Agree w you on the compressed CCJ~ definitely easier to haul around compressed... then just mix at the pots/bathtub. Tossing it dry is also much easier! Since I rinse, never really found any issues w using the bricks vs the bags. I mix my grades too, so fig was already doing some back work anyway...

TM~ think you make a real good point. It has been appx 2 years since I last used the CCT... played w the mixed chips. AND, when those measurements were made... 650-720 from my notes. It was the "best" insofar as lower ppm counts at run-off. Sounds like I need to give them another go. The reason I never followed up w them is that my shop at the time had boxes of the CCG, which I went w & just continued to use... liked the texture w longer fibers. The CCT was comparable if I recall properly. Shit, going to get my next box w the CCT. Thanks TM!!!

TY SB & Smokin~ greenest of vibes all!


thx for the info. grohi have you ever tested coco from a pet store? it is mainly all peat consistancy. i have never tested but grew 2 cycles & about to start the third. i think ive been pretty lucky cause i dont even use a tri meter. yep never once checked ph & never had a lock out or any other prob. although i do a similar ritual as you do pre plant. i get 3 bricks for $7 out da door. food for thought.

im gettin giddy as for i got some cleaning & reworking to do b4 i fire up the light. running full line of GH's organic line called general organics w/ subcultures b & m. def will have a detailed GJ


I've been meaning to measure some "alternative" sources & even try a small single plant run... interesting.

I will pick some up & repost/edit it here. ONLY if you give us some details on the GHO line... really interested! ;-) Peace brother.


soon as im up & running ill have a GJ. unfortunately i had been down for a lil while so im popping 5 citral seeds w/GHO in search for a mom so i can do a coco scrog w/ GHO. hopefully ill have eniugh nutes for 2 runs so i can m,ake a fair judgement. but i believe it will kick some arse.


invaluable information here GroHi, much respect. i was thinking of going the coco route for my new setup, as i've heard so many great things about it. i'll definitely be flushing it first off before using it. thanks!


What's up good people.

I started using coco in the beginning of last year and I love it. However, the only coco I have access to B'Cuzz, Botanicare, Sun Leaves and I think Empire Organics. I only use the B'Cuzz chunky that comes in brick form.

I don't use the other stuff due to reading to many horror stories.

So what I do is hydrate the stuff with aerated water at PH of 6.0, my water comes out at about 56ppm from the tap btw.

I usually do about 4 bricks at a time. So in this soupy mix of hydrated coco chunks I usually add about 2tbsp of Clearex and let it sit for a day. Then I drain and rinse it with 5ml per gal of Cal-Mag and .5 ml per gal of H&G Drip Clean.

When all is said and done my ppms are just over 100. The only other thing I do to it is when I transplant, I add Espoma Mycho(1 scoop per container) and feed by hand with home brewed tea consisting of water soluble plant success mycho(1 scoop per gal), superThrive(1ml per gal) and molasses(2tbsp per gal).

Gives the girls a quick jumpstart and I got fresh white fuzzies poking through the bottom with in three days or so.

The rooting process is even faster with H&G Roots XL, but that stuff is out of my price range :rauch08:.

This is a work in progress but that's how I have been doing it lately.

Good topic btw,


GroHi good info. I've been using Botanicare Ready Gro which also has a high ph runoff along w the ppm. I was using RO water at 6.3 ph but recently went down to 6.0 after reading a sticky by Texas Kid saying that coir is hydro and should be in a range of 5.8 - 6.1, not 6.3 - 6.9 as I'd been at.

On my next run I'm going to try your flush w tap till it's clear than RO w CM at 6.0 and see what happens. Hopefully this will help because I've had to flush my mom's and they always go funky for awhile after a flush.

Thanks for the info
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