So let’s do simple math take 100% and subtract the 25% castings and u have 75%, then let’s look at the white specs of perlite all over, safe to assume 20-25% perlite so now ur at half coir MAYBE 55%, then throw in the other amendments and ur about 45-50% coir. That’s an organic soil mix, just diff mix percentages. How u cross those hairs and call that a 90-100% coir grow is beyond me
My link for my build a soil recipe ain’t far off when I suggest 25%coco, 50%compost, and 25% perlite and a cup of Dr earth per 10 gallons.
Still fail to see how 45-50% is a mostly coco mix, half coco mix is more fitting if anything which does land under soil organics but again ain’t the 90-100% u came in swinging with trying to say what it is and stand by my original comment of if your using 90-100% coir that’s not a soil mix anymore that’s soilless
Soil organics recipes are always gonna have something for food(compost) drainage and aeration(perlite or lava rock) and water retention (coir or peat).
It really doesnt get anymore basic than that