The yard waste centers are the quickest way to get the materials.
It is true that you can't control what is sprayed on them prior to
composting. However, one would hope that a good bit of anything present
is going to be diluted by the much greater volume of untreated material,
and degraded by the composting process. At least, it never stopped the
weeds from eventually pushing through on my lot.

Other less reliable sources include tree chippings from some of the
smaller arborists, who might otherwise have to make a longer trip to a
dump; bags of leaves (this is the wrong time of the year for it) that
will be collected in the fall (make sure to ask before treading on
other's property); and manure and used bedding from equestrians.

The best place to get the latter (manure and bedding) is from a boarding
farm, where there will be a much greater quantity available. (When I've
asked, I've also volunteered to help with the stall cleanout.)

The other option is to grow it... a green manure can produce a lot of
plant material that you can turn in come fall. Clover comes to mind.
(See http://attra.ncat.org/attra-pub/covercrop.html)

Clays actually have a lot of nutrients in them, and it is usually the
consistency that people worry about more than the fertility. I've heard
of people using gypsum to loosen up certain kinds of clays, but this Web
page - http://www.taunton.com/finegardening/pages/g00012.asp - (by an NC
extension associate) says that the clays in this area don't need it.




Chuck Jurgens wrote:

I have some really bad soil (clay) in my yard and want to ammend it with
organic material. Looking for free and/or cheap manure, leaves, mulch -
anything I can til into the soil to help enrich it.

Chuck
jurgens..at..bellsouth..net