[Arid_gardener] Question from Home-Hort WWW page

[Chris Trask]

     Adding amendments to clay soils such as we have here in the Lower
Sonoran region is not sufficient, as I have found out over many years.  The
most effective remedy is to remove it entirely to a depth of at least a foot
and replace it with a 1:1:1 mixture of soil, sand, and organic matter
(compost or mulch).  You can buy that mixture from most landscape material
suppliers, but I would recommend doing a simple soil test to be sure that
the clay content is in the vicinity of 10% to 20%.  A publication from the
Colorado State University Master Gardener program describes a very simple
method:

     http://cmg.colostate.edu/gardennotes/214.pdf

     A sandy loam soil is considered best for growing desert plants.  You do
need a small amount of clay as this is the material that is used to form the
rhizosheath that protects the roots when the soil dries out, which is one of
the survival mechanisms of drought-tolerant plants.

     Adding gypsum is at best a short-term solution, after which you will
end up with the same clay soil but with more calcium.  The impermeability
(decreased water penetration) caused by the clay is a serious problem for
which there are very few long-term solutions.  I spent years removing mine a
little at a time until I ended up with a good garden soil about a foot deep
everywhere.  Not something I would recommend doing this time of year.


-----Original Message-----
>From: annkz!@gmail.com
>Sent: Jul 12, 2007 7:42 AM
>To: arid_gardener at Ag.arizona.edu
>Subject: [Arid_gardener] Question from Home-Hort WWW page
>
>Ann K
>85212
>annkz!@gmail.com
>
>What needs to be done to amend very dense clay type soil? I have a small
backyard with no plant life and would like to add suitable varieties to this
full sun environment.
>
>
>_______________________________________________
>Arid_gardener mailing list
>Arid_gardener at CALS.arizona.edu
>http://CALS.arizona.edu/mailman2/listinfo/arid_gardener


Chris Trask
Outings Leader, Sierra Club (1981-1991)
Palo Verde Group Outings Chair, Sierra Club (1985-1988)
Grand Canyon Chapter Outings Chair, Sierra Club (1988-1991)
Member, Arizona Native Plant Society
Member, Arizona Governor's Advisory Council on Invasive Species (2005-2006)
Member, Arizona Riparian Council
Member, Central Arizona Weed Management Area