and although not necessarily high in
nutrients, it provides a rich environment for
the roots. It is acidic unless limed. Some
commercial composts are nothing more
than chopped up dried plant matter. This
material may add some organic matter to
the soil, but is not the same as real
compost.
WORM CASTINGS - is compost
digested by worms. As they digest the
ingredients they concentrate them so that
the nutrients are readily available to the
plants. It is a excellent ingredient in mixes.
HUMUS - is a compost produced in a
very moist environment. It is very fine
textured and rich in nutrients, but is quite
acidic.
COMMERCIAL POTTING MIXES - are
not soils at all, but mixes containing
ingredients such as tree bark, peat moss,
wood by-products, as well as artificial
ingredients. These mixes have virtually no
nutrient value unless fertilizers have been
added. Usually mixes with organic
ingredients are long on carbon compounds
and short on nitrogen, which means they
need fertilization. In a controlled
experiment, researchers with the California
Dept of Agriculture found that commercial
planting mixes vary in their ability to support
plant growth, even with fertilizers added.
There was no way of telling which mediums
were best without testing them by growing
plants in them.
VERMICULITE - is puffed mica which