In article
,
Billy wrote:

In article ,
"David Hare-Scott" wrote:

Mike wrote:
What is the usual treatment for hard clay soil, should soil this bad
be dug up and replaced?

What I started with: http://img20.imageshack.us/my.php?image=soil1.jpg

As others have said you will need to break it up with much organic matter.
And as drainage may be a problem doing this in raised beds can be an
advantage. Also you will get some help breaking it up by adding gypsum
depending on the clay minerals present. Broadly gypsum makes smectitic
clays clump but not kaolinic, right now I cannot find the test used to tell
what you have but there is such a thing if you are prepared to go looking.

As for the decision to remove it and import soil that depends on the
situation. If you have a small area, want quick results and have the money
to spend then replace it. You are looking at the price of new soil, quite
a
bit of earth work and somewhere to dump the old soil.

If going this route take care not to build a pond. Assuming you have a
solid layer of clay and dig a big flat hole in it which you fill with nice
well-draining soil. If you have heavy rain your plot has only as far as
the
edges of the hole to drain to then it fills up with water as the clay
around
it is impervious. Then nearly all your plants die. You need to plan and
build drainage for the whole area as part of the replacement.

David

On the other hand, I started with rock and clay soil and never had this
problem. You may want to look at the article on clay in Wikipedia and
its links. If this garden spot has had a problem with standing water,
drainage would be wise. The adding of amendments (manure and organic
material) and the turning of the soil, may cause your garden area to
mound which would keep the roots above water in any event.

After all that good advice on clay soil - I will just add the book:

"Gardening - when it counts" by Steve Solomon.
ISBN-10: 086571553X
ISBN-13: 978-0865715530

The author has good advice on mending clay soil.

Enjoy Life ... Dan

--
Garden in Zone 5 South East Michigan.