Soil: A Breakdown

Soil: The Base and Minerals

Part 1: The Base Soil

(Sphagnym) Peat Moss

            A Peat Bog is an old swamp of decaying organic matter, a unique ecosystem that must be dried and drained to harvest. Hundreds of varieties of mosses compete to decay the organic matter- this ends up in the product as well- hence the name "Peat Moss." The PH of this medium is on average 4.0 (very acidic) and provides no significant nutrients to your soil. Usefully, Peat is a very fluffy texture that can be used to positively amend clay-like soil for drainage.
But (Author's Opinion) composted organic material can provide sufficient drainage with the added benefit of organic nutrients and a naturally-balanced PH. With the unsustainable harvest of Peat Bogs in mind, alternatives to this product should be preferred. 

Humus

             A stable form of decomposed organic matter. Contains low amounts of Nitrogen and other macro-nutrients, but provides roots with an atmosphere to thrive and a stable PH. Microbes in the humus facilitate a healthy balance of life in the soil/root system, while the fluffy, non-compacting structure of the medium provides excellent drainage and aeration. Will increase water-holding capacity of sandier soils and drainage for clay soils; a great base to any true soil. 

Coco Fiber

             Coco fiber/dust/pith are the natural byproduct of the coconut harvest. Twenty years ago it was not a very useful growing medium, however the industry has developed a process of leeching the salts and now high quality coco fiber is afford and available just about anywhere you live. 

Advantages:

1. Texture: sponge-like, this fiber can retain more water than a typical soil (8-9x it's weight) while also providing more oxygen to the roots between waterings because of the abundance of pores found naturally.

2. Natural Root Enhancer: Trichoderma fungi is found in coco fiber- it forms a symbiotic relationship with the roots, promoting optimal health and protecting against pathogens and "root rot."

3. High CEC (Cation Exchange Capacity): Means the coco fiber can store lots of useful nutrients for the plant to consume as needed. So harder to burn or underfeed the plant once established. 

4. Slow Breakdown: Means the fiber can be re-used multiple times (even years)

5. Sustainable and Natural: Feel good about using a medium that is renewable and better for the earth.

6. Taste: Characteristics of Flowers grown with coco: they seem to cure quicker and smoke smoother

Notes on Coco:

Can be successfully mixed with soil mediums to enhance soil structure (you will notice improved root growth). However, used alone, coco needs PH of 5.5-6.0 and complete nutrients added with emphasis of a little extra Calcium (as some Ca is absorbed into the medium). 

Part 2: The Minerals

Domolite Lime 

             This is a mineral rock with useful sources of Calcium and Magnesium which can also be used to raise and stabilize the PH of many soils. For immediate results, purchase the fine dust which more quickly dissolves. For longer-term applications, pellets work just fine as well. 

Gypsum

             Made of Calcium Sulfate, this product is a solid source of Calcium and Sulfur. Contrary to many claims, Gypsum does not improve the structural quality of soil (drainage, aeration, etc) alone. However, it can provide benefits to breaking a hard crust on soil where there is excess sodium (i.e. salt flats). 

Azomite (A-Z Of Minerals Including Trace Elements)

            Mined from a specific source of volcanic and rock dust from Utah, this product has a comprehensive and balanced array of 70+ trace minerals or "micro-nutrients." This makes a great addition to any well-fertilized garden and will boost the immune system, overall health and nutrition of the fruit.

Rock Phosphate

             This is a very slow-release soil amendment (1+ years for full breakdown). Additionally soil needs to be naturally acidic (PH<5.5 according to http://www.soils.wisc.edu/extension/pubs/A2520.pdf), and absorption also depends of the particle size of the rock phosphate and the presence of mycorrhizal soil fungi, which help along the process.

Epsom Salt

             AKA Magnesium Sulfate (MgSO4) breaks down into quickly usable forms of Magnesium and Sodium for your plant to use. With a slightly acidic PH, Epsom Salt can be used as a marginal form of PH control also. It should be noted; where there is no deficiency, an increase in specific nutrients can throw off your whole nutrient balance, causing a shortage of Zinc, Calcium or Potassium (in the case of excess Mg). 

Perlite

             Volcanic rock which is cooked at very high temperatures until it "pops" like a corn kernel into an expanded, very porous substance. When added to soils (5-25% by volume usually), drainage is increased greatly- while some water retaining ability is sustained by the pores' ability to store water. For best drainage properties, "Course" grades of perlite are preferred to finer grades.

Vermiculite

             Sometimes said to be exchangeable with Perlite, vermiculite is not. Although they are both volcanic rocks, expanded through the process of heating, two key characteristics are different. 
1) PH of vermiculite can be much less stable over time, due to its chemical structure. Also there is no guarantee of a neutral PH in its original environment.
2) Vermiculite has a much higher Cation Exchange Capacity (CEC) largely because it absorbs much more water and nutrients. However, this works directly against the reason of adding the substance for better drainage. 
Usage Recommendation: Has been observed as a positive ammendment to soil, but my own experiments are limited.