"KT" wrote in
ups.com:

The soil here is hard-packed clay. I think I'd need dynamite to plant
anything. I know that if I add organic material it will help a lot,
but if I add inches of manure or compost, doesn't that change the
grade? We had problems with water in our crawl space in the last house
we had, and I don't want to raise the grade so that rain runs back into
the foundation. If I add the organic material, does it break down over
the summer so that the slope of my yard doesn't really change? I hope
this makes sense - I don't know if I am making myself clear. I want
better soil - but I don't want a wet crawl space.


You can simply top-dress with any good organic material, and over time it
will leach downwards and really improve the soil structure. Scratching the
hardpan surface first will help start the process, as would doing something
like core aeration (as is done with turf). In very compacted conditions, I
suppose it would be possible for thickly laid top dressing to wash away in
a hard rainstorm (as rainwater sheets across the hard surface), in which
case you would need to rethink how you're going about soil improvement.

As to how quickly organic material is leached into and incorporated into
soil structure, there are so many unknown factors it would be foolish to
predict.

--
David J. Bockman, Fairfax, VA (USDA Hardiness Zone 7)
email:
http://beyondgardening.com/Albums