GREEN THUMB GARDENING
by Michael Bloch
Dirt, or more accurately, soil, is amazing stuff
and something that we very much take for
granted. But not all soil is created equal. I’ve
been fascinated with soil since I discovered
how long and how much material it takes to
make it.
For the sake of clarification, let’s make a
couple of distinctions:
• Dirt - mainly mineral-based—pebbles
and finely ground rock
• Soil – mineral-, plant-, fungi- and
animal-based
It’s easy to tell dirt and soil apart. Soil will
usually be dark in color and have a rich earthy
smell. Dirt just tends to smell like dust. There’s
a lot of dirt around the world; it’s in plentiful
supply. The problem with dirt is that it’s a
filler and has very little nutrient content as
it’s primarily composed of basic minerals like
calcium and iron. While these are required
to some degree by plants, the real life-giving
properties are in soil.
Soil is a smorgasbord of nutrients; animal
droppings, decaying plants and creatures add
84
Maximum Yield USA | March 2012
to its fertility. It contains a multitude of life
forms including insects, fungi and bacteria—
it’s an ecosystem unto itself.
The soil/worm connection
“B” horizon is almost entirely rock material,
plus some nutrients that have washed out of
the “A” horizon. The “C” horizon is mainly
bedrock in various states of weathering and
extends to a depth of thousands of feet.
I began to understand how much matter
it takes to make soil when starting a worm
farm. In that scenario, the worms break down
the organic material leaving what is basically a
very rich soil. Worms are a crucial part of the
soil ecosystem.
I put hundreds of pounds of waste into my
worm farm during the first year and at the
end of it I still wasn’t able to fill the worm
bin up with castings. All that organic waste
breaks down as it primarily consists of water.
Soil horizons
Soil layers are called horizons. The very top
layer is called the “O” horizon. It