15% peat moss, pine bark, or coco coir
35% aeration (I prefer Perlite or rice hulls but course Sand, and pumice are other options
50% composted organic matter (this could be compost, composted cow or horse manure, worm castings, leaf mold). I prefer a combination of as many different kinds of compost I can but whatever is available to you and the best quality is what you should lean on.
Neem Seed Meal or Neem Cake 1/2 cup per cubic foot
Crab shell meal or shrimp shell meal 1/2 cup per cubic foot
Gypsum 1/2 cup per cubic foot
Langbeinite 1/4 cup per cubic foot
Kelp meal 1/2 cup per cubic foot
Alfalfa meal 1/4 cup per cubic foot
Oyster shell flour 1/4 cup per cubic foot