Cation exchange in coco and why it matters

Anyone else grow in coco and can help shed led some light on this topic I know very little about it and it’s hard for me to understand exactly how it works and how to replace the stores nutrients in the coco

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How I understand it cations are like micro tubes and coco coir naturally has those tubes filled with potassium and salt if not properly doubled or triple washed so you soak the medium in cal mag water to bind to the potassium so that it doesn’t pull it out of given nutes.
Basically fully submerge your fabric pot of coco up to soil line in cal mag water at a 1.5 x dose recommended on bottles for 8-12 drain then repeat once more


I’ll try to keep this incredibly simple.

  1. Coco coir is inert. It doesn’t provide nutrients or take them from the plant.
  2. Calcium does bond with coco coir at sites on the exposed surface of fibers.
  3. Coco coir fibers constantly break down during a grow, exposing new fiber surface.
  4. Therefore, before the grow we soak the coir for as many hours as we can in a very strong (3x) CalMag solution, rinse it thoroughly, and then add our perlite.
  5. Afterwards, you will need to ensure adequate CalMag in your solution, so that plant has enough in spite of the medium bonding with a small amount.

It’s not a big deal, especially if you keep your containers on the smaller side.

Edit: also, coco coir isn’t soil. It’s a soilless mediums.


All of the cal mag problems I had in coco magically disappeared when I started watering 6-8 times per cycle. I use 900-1200 ppm jacks classic 5-12-26.

I never pretreat blocks and I reuse my coco up to 4 times.