TrippleDip
Well-Known Member
Soil lab can be as simple as a microscope and scale - You can count bacteria and fungal hyphae and find your bacteria-fungi ratio. Size of hyphae will tell you how mature your soil is. The percent organic carbon and moisture content can be found by simply heating it up (and weighing). Percent carbonates by heating it even more. Percent inorganic C by disolving in acid. The ratio of sand-silt-clay can be found by disolving in water and letting it settle. You can heat the soil up over some antifreeze so you can count and see the variety of microorganisms such as microarthropods and nematodes.
They also sell very cheap (mine was $30 for 60 of each test) test kits for NPK+pH which are basically put soil in water, add chemical 1, add chemical 2, compare colour to index card. N tests are basicslly useless though and will just track rainfall unless you have basic soil.
Potting mixes are about 50% or more mineral (not counting water). Compost and peat moss are about 50% mineral/organic.
I would agree though that some mixes/peat are lacking in specific minerals more likely to be found in soil due to soil being built from basically bacterial/fungal breakdown of rocks.
