"Ted Shoemaker" wrote in message
m...
What exactly is good soil? I used to know, then I have heard too many
answers to this question to think that I know any more.

In particular, I am talking about a soil that is natively clay, in
zone 4 or 5, used for flowers (both annuals and perennials).

Some people say, ADD SAND. Other people say, No, if you add sand,
you'll just lock up the clay and make "concrete" out of it.

Some people say, ADD COMPOST. Other people say, No, if you add
compost, you'll lower the pH too far.

And similarly for adding manure, Miracle-Gro, lime, bark, lawn
clippings, dry leaves, etc etc etc.

Can somebody who really knows, please settle this?

Thank you very much!

Ted Shoemaker

Good soil for the majority of plants is one that is neutral to slightly
acidic in pH, well draining but moisture retentive with a moderate organic
matter content and and a healthy population of soil organisms. The best way
to lighten heavy clay soils is with organic matter and the best organic
matter is well aged compost. Compost is virtually neutral as far as pH is
concerned and nearly all soils will have a buffering capacity that will
resist substantially changing the pH anyway. Clay soils have a very high
buffering capacity.

You can lighten heavy soils with gypsum or coarse sand but you will need a
lot. And the sand must be coarse. Too little sand or too small a particle
can contribute to the 'concrete' effect. And neither contribute organic
matter, which promotes the populations of soil organisms that assist the
plants in metabolising the nutrients in the soil they need to be healthy.

Miracle Gro is a fertilizer. It does nothing to improve the quality or
structure of soil and can result in a build up of fertilizer salts if used
excessively (as will any chemical fertilizer).

Lime is a de-acidifier used to 'sweeten' very acidic soils. Since the
greatest majority of plants prefer a soil that is slightly acidic, unless
your soil has a very low pH, adding lime is typically not necessary unless
you are growing plants which require neutral or slightly alkaline conditions
(like a number of veggies). The exception are lawns, which grow best in
nearly neutral soils and lime will help to deter the development of moss in
lawns also.

Bark, lawn clippings and leaves can be used as mulches or can be
incorporated into the soil to add organic matter or can be added as raw
ingredients to the composting process.

Very few of us have the benefit of a "good" soil to begin with - it takes
time and continual amending with organic matter to achieve what is
considered ideal - a loose, friable soil with varied texture and high
fertility.

pam - gardengal