What I've learned is to replicate what happens in nature. Nothing is ever tilled (which is very destructive to the balanced layers of microbes and soil structure) and fertilizer like manures, composts, leaves, etc, are all applied to the surface.
I apply the composted materials in my chicken coop and run (manure, leaves, hay, wood product, and whatever scraps the chickens don't eat) to the surface of my garden area AND my potted plants, and they all do amazing. Its actually the perfect system for potted plants because every time I water, it carries some of the nutrients down, and the amount that I water directly corresponds with the active growing season (i.e. you don't water much in the winter months). I usually have a few earthworms in my potted plants as well, so they come to the top to feed and then carry those same nutrients down to the root system, which by the time it has gone through a worms digestive track, it is that much more perfectly bio-available for the plant.
I even apply this stuff sometimes when it is not fully composted by the way, with no detriment. Again, if you till it into the root area, it will of course burn the roots, but if its at the surface, it shouldn't hurt anything unless you really piled it up or something.
You cannot compare composted organic material to chemical fertilizers like Miracle Gro. The former will build your soil in the long run, and the latter will destroy your soil in the long run. They are chemical and salt based, which is destructive to soil life. Again, I'm talking long-term. Furthermore, compared with lab-based chemical fertilizers which only concentrate on the N-P-K values, composted materials have so much more than just the N-P-K, but also include all of the trace nutrients and minerals that plants love. This is why our produce doesn't taste as good as it used to, as our soils are getting more and more depleted.
Guarantee there will be a difference in the taste of a fig that has been grown in mineral, nutrient, organic material-rich living soil and one that has been sitting in just potting soil and Miracle Gro for years.
Hope this helps.