Calvin...
I grow in the gritty mix, but use the Foliage-Pro/Pro-TeKt cocktail, very diluted with each watering. I gave up on the organics because of the damn stench when they start to decomp. I had every Housefly in a 20 mile radius living near my fig trees. The fish juice was the worse.
I like a lot of the fer'ts. that are developed for use by the pot-growers. That's where I buy all my supplies...from the local pot-growers supply stores.
I wish I had your option of sinking my containers into the surrounding soil. personally, I think in-ground has many advantages over container culture, and is a more natural approach to gardening. I containerized my figs because of my lousy climate, and because I must store my trees in my unheated garden shed. So, containers give me the mobility that I need. In another life I would live in the semi-tropics, so that I could grow without these worries....or, have a nice glasshouse. Not happening, so... I do what I must do.
Hope to read som more comments on this thread. Information is always good to share.
Frank