So the store bought (cheap) compost I buy works primarily because of the slow release fertilizer they put in? It's just a medium for keeping moisture levels constant and to supply fertilizer to the plants?Correct. Pots are manipulations where the inputs are not controlled by nature. In the soil the bacteria, through enzyamatic dissolving, can even break down rocks and minerals. The plants exchange carbon for this service, and the bacteria are a fertilizing food source for fungi. I do not know if you noticed, but the fall leaf drop is supplemented with fresh greens and other storm droppings across a year in the forest. 1 application of compost is not enough, nor full cycle naturally speaking. And there is nothing in coir or pear moss to eat the compost, so it breaks a natural cycle.
Demonstrated symbiotic relationships such as the endo (inside) and ecto (outside) mycorrhizal connections to roots systems are part of the voodoo legends surrounding the mysterious yet natural no dig concepts. I say that because I have never seen a plant dig a hole for its seed.
On the other hand when I have let my garden run free it turned into a less productive environment. Too much uncontrolled competition is the problem with natural selection and modern productivity expectations for gardening.
If you lower your expectations or plant more seed it is less work but takes more room. Again I have never seen a tree with a bank account to own a deed so we all try to be economical gardeners. The various themes about different types or methods of gardening are usually combined on the internet and it causes confusion.
Indoors and Hydro, pots, raised bed, in ground planting all have a cycle that is different some ways to each other. Recognizing those differences requires a certain distance or perspective and it seems a human condition to see the trees rather than the forest. Then again I have seen trees in very large (Huge!) pots so technically one might point out that there are transitional moments between methods. But mostly it is simpler than all that.
No dig is a old offshoot of the forest floor. Recently it aquired a sexy new marketing campaign via the internet chat rooms. But what works in one area will not in another. My weeds can grow faster than a squash plant and that is impressive.
One thing I've tried this year (and so far it seems worthwhile) is to cut the bottom off of large pots and place them on the soil. I've used this for potatoes - so a cross between container grown and in the ground. It's worked extremely well - I've had my best crops from these tubs. Better than in ground, container grown and raised beds.
But my main reason for doing this is I figured I could treat them like garden beds - instead of emptying them out and replacing the compost each year I plan to put a few inches of fresh garden compost on top.