I dont know if there is some sort of secrecy when it comes to soil mixes, I have tried many different types and to be honest as long as the soil is loose and drainable, I think my pepper plants love it. I haven't really been able to compare with no one else until I joined this forum. For my starting mix i used 1 part compost, 1 part sunshine #4 , 1 part of worm compost, 1 cup of humic acid and 2 tbsp of rock dust, so far I been really happy. When it comes to the adulthood of my plants I use.. 5 gallon compost , 5 gallon top soil, 2 gallon vermiculite 2 gallon perlite , 1 cup rock dust, a small sprinkle of bone meal and the secret of all secrets and I dont think its much of one is MESQUITE a small chunk of it on top of my plants ... an old farmer told me once that every time u water your plant the mesquite will soak and slow release their minerals that will make the peppers grow big and spicy ... dont know how truth this is , but its been working for me... so what yours?? if your willing to share the knowledge acquire .. thanks