Demystifying Dirt: Soil, Potting Mixes, Compost, Peat and Earth Explained!
"We know more about the movement of celestial bodies than about the soil underfoot." ~ Leonardo DaVinci
Confused about what organic growing is really all about? You're not alone! Here are some clear and concise definitions of commonly used and confused items. We'll also introduce some fundamental concepts of organic cultivation.
Common peat-based potting mix
Sphagnum Peat Moss
Extracted from peat bogs, prolific in Canada and Northern Europe. The upper layers of living sphagnum moss are stripped off and the lower layers of partially decomposed moss are extracted. It is naturally acidic so dolomite lime is added to raise pH. It is low in plant nutrients, but holds water well and is consistent.
A coarse, white substrate created by heating volcanic rock to the point at which it puffs with air, much like pop corn. It is used to improve the drainage and structure of peat- based potting soils, while improving the air filled porosity.
Sustainably harvested from coconut husks, coco coir is the product of aged husk milled down to a fine pith. It can be used as a sole growing medium, but is also used to lighten / aerate peat-based potting mixes.
This ideal, outdoor agricultural soil is sometimes added to potting mixes to boost nutrient content and improve cation exchange (the ability of a growing medium to absorb and release nutrient elements). Loam is heavy so is not often added in large quantities.
Aka “worm manure” or “worm poop”, these are the nutrient rich product of earthworm activity. When worms eat good quality foods, they produce good quality “casts” that are highly active in beneficial biology. They also improve potting soil overall health and speed up nutrient cycling.
Composted Green Waste
Composted materials are renewable and are increasingly used as a component of potting mixes to improve structure,nutrient content, and biological activity. The source of composted green waste can vary greatly from municipal kitchen waste collections, to commercial gardens or parks trimmings.
Composted Bark / Other Woody Materials
The waste product of wood processing, bark, wood fibers and other carbon-rich materials provide resistance to compaction and help to improve water distribution and drainage. Woody material first needs to be partially composted to prevent nitrogen draw down.