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Clay Soil Amendments

I live in Orange County, CA. - the adobe capital of the world! It is my
personal experience, and the opinion of many others, that coarse river sand
is THE BEST possible long-term amendment to clay soil! That "it makes
bricks" argument is nonsense! - unless you allow your soil to dry out
completely. You wouldn't do that to your roses, would you?
 An additional amendment to clay should also be gypsum. Gypum (calcium
sulfate) helps break up the clay clods, making it easier to blend in other
ingredients. It does this by a chemical reaction with the sodium salts in
the clay. In doing so, it also allows these toxic sodium compounds to be
leached out of the root zone. Add 10 to 20 pounds per 100 sq. ft. and water
it in a few days before you plan on adding the other amendments. Other
inorganic amendments, such as perlite, are also good but expensive.
 Organics are great, of course, for not only breaking up the soil, but for
adding nutrients, and feeding the earthworms and beneficial bacteria.
However, they don't last - they decompose, and are consumed by the roses and
the earthworms. Once they are gone, you are back to clay soil again! Unless
you plan on digging up your rose beds every few years to replace them, I
would suggest a balanced application of sand and organics.
 If you have clay soil REPLACE two-thirds of it with a mix of 50% sand and
50% various organics - manure, oak-leaf mold, mushroom compost, redwood
compost, etc. Various amendments are available in different areas. Make sure
that any manures have aged for year. The best strategy is to vary the
organics according to their decomposition rate. Manures will decompose very
quickly, while redwood and other ground barks take much longer - stretching
out their benefits.
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