The Only Good Use for Peat Moss
Potting soil should be light weight, but I do not recommend peat moss potting soils. Peat moss is anti-microbial. Microbes don’t grow well in it. That’s just the opposite of what we want. Peat moss is excellent for storing bulbs and potatoes, or shipping food or other perishable material that would otherwise decay. Potting soil should not be sterile. It should be alive and dynamic. It should be light, loose, well aerated, fertile, full of microorganisms and have the ability to stimulate quick and sustained microbiotic and vegetative growth.
Potting soil mix (photo via U of Mississippi U Extension)
My recommendations for a specific formula have varied through the years, but the latest recommended formula* is a follows:
60% Compost (compost, humate, coconut fiber, coir, earthworm castings, coffee grounds, etc.)
30% Rock (lava sand, natural diatomaceous earth (DE), zeolite, granite, etc.)
10% Sugar (corn meal, dry molasses, wheat meal, etc.)
*This mixture is not available commercially. Hopefully it will be sometime soon. For the time being, you'll have to make it yourself.
Other amendments that are beneficial in small amounts include greensand, beneficial microbes (bacteria and fungi) and organic fertilizers. For fertilization use fish meal, kelp meal and alfalfa meal. Garrett Juice and Garrett Juice Plus are also excellent fertilizers for plants in containers. Also products are available in the Dirt Doctor Destination or your favorite Garden Center.