Retiredguy, the best garden I ever had was when we lived in a 50’ era subdivision with alleys. Everyone put their lawn clippings in the alley for the city to collect – I collected it instead and put it directly on my raised beds – awesome!
As for tired soil, I agree for the most part that as long as there is soil of a sufficient depth, bringing in new probably isn’t cost effective. This would be my plan for what it’s worth.
Do a soil test, specify trace mineral screen. Add any trace minerals that are missing – crop rotation thereafter and barnyard manure will go a long way to preventing losses in the future.
Check for compaction, if there is ‘hardpan’ down there roots won’t penetrate far and there is a chance of water not draining and suffocating the roots.
Manure liberally.
The best method I know to improve overused soil in larger areas is green manure. Basically growing high ‘bio-mass’ plants in place and incorporating them into the soil while green – usually before or at flowering. The plants produce proteins that convert to nitrogen as they decompose. Leguminous plants like the clovers or vetch also actively fix nitrogen in the soil - be sure to buy an inoculant for the particular legume seed you plant. The fibrous carbon part of the plant decomposes more slowly improving the texture of the soil allowing faster warming and improved aeration and moisture holding ability.
Cover cropping should be, IMO, an ongoing strategy – never leave the ground bare. The reason it isn’t practiced more is it reduces profits short-term.
As a side note, I saw at the feed store a bag of some kind of additive that is supposed to promote bacterial and fungal growth in the soil – it was labeled ‘organic’ for what that’s worth. I’ll look at it next time to see what it contains and the name.
A good primer on green manures:
http://www.attra.org/attra-pub/PDF/covercrop.pdf
“How does soil work”:
http://www.peakoil.com/fortopic1452.html



