My standard mix 3 parts pine bark fines, 1 part pro-mix general purpose potting soil (instead of pete, it's pH balanced, mix is mostly peat and perlite) and 1 part composted manure, bagged, and 1/3 part DE the size of perlite. I add Dynamite Control release, and whatever organic fertilizer I have on hand, I think in these I used Tomato-Tone. Once a month I add more organic, last time is in August. Sometimes I use other additives, like oyster shells. I had some to feed the grub eating bacteria I'm trying to grow in my grass. If you put chitin in, chitin eating bacteria will come,
Chitin eating bacteria will eat the chitin in living grubs and beetles. After I did the lawn, I had some left so some went in the various potting soils, which will eventually be used in my raised beds when I change out soil.