You quadrupled your compost input so the comparison isn't really a fair one. The compost pot has a lot more food in it.
Wasn't meant to be fair.
You had suggested coco as a carbon source when I was thinking compost so I thought I'd compare the two. My thinking was that (mostly) finished compost had a good amount of carbon in it but also food plus microbes, so that's what I was testing. Mostly to see if I could get around the need for coco at all.
When I originally was testing base inputs to see what I might be able to use to replace CSPM, I ran some tests using coco, CSPM and my leaf mold, and found the leaf mold better than coco in some respects (
Experiment post here ).
So, if the compost can supply the needed carbon but also has other properties as well, it would seem to be a much better input in my situation especially in small containers. Plus, it's local to me and I can control the inputs. Plus, I can produce it in a matter of months rather than years it takes for the leaf mold. Plus, it has a much more varied source of inputs, including leaves for the minerals, but I can also add my comfrey, nettles, flowers, and calcium to it. It should be much superior to leaf mold with all of those additional inputs plus a wider variety of microbes all while providing good humus to help with tilth.
Plus, plus, plus. What's not to like?
Try that compost mix again but compare it to itself with coco added and see which is better, then pick a path.
If I can get it done without coco at all, that's what I want to do. So, I'll see how far I get with the twins and then see how I want to tweak things from there. I'm currently thinking about getting rid of the aeration component altogether and replacing it with soil worms just like Mother Nature does. That would allow me to put even more compost and maybe old soil into the pot to extend the time frame before I have to supplement with my extracts, though I have been doing that weekly.
That will verify your carbon one way or another. Once carbon is adequate then fill the rest of the pot with food. Not enough carbon will screw you, too much takes up food space.
The twins are a good side-by-side experiment since I will see what the time difference the extra 20% compost makes before the leaves start yellowing. So far it's been about two weeks.