My mix (makes ~5 gallons before I add ~1/3 of that in perlite so ~6.5-7 gal total)
I use a small pot (~1.6 gallons) to mix up my soil and use “parts” of it to measure
1/3 (~1.6 gal) good potting soil (I use Dr Earth Pot o Gold)
1/6 (~.8 gal or half the pot) coco coir and 1/6 (same) peat moss
1/6 (~.8 gal or half the pot) worm castings and 1/6 (same) compost
Amendments:
14 tbsp azomite
14 tbsp rock phosphate
10 tbsp kelp meal
5 tbsp each of Hydrofarm bloom bat guano, Down to Earth neem seed meal, vegan mix, bio-live, and bone meal, Espoma garden-tone, and insect frass
3 tbsp Down to Earth granulated humic acids and blood meal
oh and I forgot the secret ingredients:
crushed dodo egg shells
unicorn manure
and a kilo of saffron
Yes, I know my mix is excessive, but I besides the “secret ingredients,” that is really what I use and I don’t intend changing anything (except maybe the amounts, since this mix is stronger than my last). I already had most of the amendments around to make subcool’s super soil (which I add periodically to my cannabis and vegetable plants if they need a pick me up, since my last mix was weaker).
My idea for a less crazy mix (that I won’t use cuz I’m CRAAAAAAZZZYYY):
Same basic soil medium, but following amendments:
1-2 tbsp/gal azomite
2 cups dry organic fertilizer (Espoma Garden-Tone is good)
1 cup kelp meal
Both of these mixes are basically a combination and variation on InTheGarden’s mix (Easy Organic Soil Mix for Beginners | Grasscity Forums - The #1 Marijuana Community Online) and Subcool’s supersoil.