My Soil Mix
IMHO due to variations and inconsistencies in regards to the ingredients that are contained in most organic based products that are the standard fare when making a custom soil mix it's really an imprecise science. Example...If two groups of bats are eating different diets, the bat dung from both groups of bats will not contain the same NPK ratios. Same goes for worm castings. All worm castings are not the same. Anyways, you all get the picture.
I sometimes compare building a healthy soil to what it takes to build a healthy body. If you want to build a healthy body you need to feed the machine with a WIDE ASSORTMENT of CLEAN and HIGH QUALITY foods. Eating too much of anything is usually a bad thing but eating too little of those same things are bad as well. Same goes for building a healthy and balanced soil. In most but not all cases the amounts of each ingredient are not as important as the variety of the ingredients that are used and getting the soil texture right. I won't get into soil cation exchange capacity (CEC) but those who may have a real interest in organic soil gardening monster should read up on this subject as this is they key as to how plant uptake and utilize nutrients.
I guess the point I'm trying to make is that IMHO there is no PERFECT SOIL RECIPE folks!! There are however some recipes that are better than others and the key reason lies in the variety and quality of the ingredients used. There's more to gardening than just N-P-K and Cal/Mag.
I like to try to not over complicate things unless complicated is the ONLY route to success and growing good weed ain't as complicated or difficult as most folks make it out to be.
Anyways, now that I've probably ruffled up a few feathers with the organic soil growers as well as the hydro gardeners my work is done here. LOL!
One of these days I'll take notes of the quantities of ingredients that I use when mixing up a new batch of soil.
Have a Great Day Everyone!