[harleysilo]

Originally Posted by dice

N
If you just dig out the clay a foot or two deep and
replace it with trucked-in topsoil, what you will have
is a canal full of mud whenever it rains hard. I would
leave the clay there (as a kind of nutrient sponge) and
till copious amounts of gypsum and organic matter
into it (compost, horse manure, leaves, grass clippings,
sawdust, hay, straw, whatever you can find; add some
blood meal or fish meal if adding straw, sawdust, shavings,
or wood chips, to compensate for the high carbon-nitrogen
ratio).
http://www.gardenerscorner.org/subject069317.htm
)

I hear what you are saying, but isn't adding all that stuff to the clay pretty much the same are removing the clay and putting in dirt. I can't change the whole yard's dirt composition, so really if I am planting subsurface (i.e. no-raised bed) then I'm going to have drainage problems regardless because the only design option is to plant in a big clay pot.