I mentioned using egg shells, coffee grounds and old newspapers in a recent soil amending post. Some of us live in neighborhoods that have a rather tentative relationship with our vegetable gardens at best, and they certainly don't favor our keeping chickens for their manure or keeping a compost bin on the property. Who can blame them? If a person doesn't tend to the compost bin, it can become a truly foul-smelling, rodent infested nook in the yard. For the serious gardener, however, composting is essential--all the more because in urban gardening, space is at a premium and soil must serve without the luxury of lying fallow that its cousin, country soil, often enjoys. One option is to do what this website describes as "natural composting" and it is something I've been studying this year. I'm not quite to the point where I automatically remember to take kitchen vegetable scraps out and toss them in the garden, but I'm getting closer. One note mentioned in the link: don't toss them too close to existing plants. They can create temporary chemical imbalances in the soil as they decompose, which you don't want to have happen too near a plant that is doing just fine with the soil status quo.
Another thing I'm trying is growing things with the intention of tilling them under either at the end of the season or early in it. I don't have pictures to show, but I grew peasover about half the garden, all to till under after harvesting them in the spring. Using the plant body itself this way is considered use of a "green manure" which is a good choice when real manure is frowned upon either by your neighborhood or your family. I grew an early spring pea variety for this purpose. It grew in the spot currently occupied by squash and beans before these summer crops could be planted in the garden. I may grow them again soon as a fall crop and till them under again--along with much of my marigold crop.
Marigolds work well not only keeping certain beneficial insects like lacewings and parasitic wasps interested in your garden, they also--when used as green manure--help keep soil nematodes under control. Nematodes are microscopic round worms that do damage to plant roots. But they don't like marigolds decomposing in the soil.http://ag.arizona.edu/yavapai/anr/hort/byg/archive/marigoldsandnematodemanagement.html%22%
More options on soil additions: grass clippings. If you bag them when you mow, you're all ready to spread them around on the garden--just make sure you don't use grass grown tall enough that any weeds have gone to seed. You hardly want to seed weeds into the garden intentionally!
Finally, we got my husband a free-standing back yard fire pit for his birthday this year, and the wood ash left over from its use can find its way into the garden. I've read, however, that wood ash tends to be a soil amendment that people overuse. Before you use much wood ash, get a pH test kit and make sure you even need it. Ash "sweetens"soil. Read the links included here to see how to check whether yours needs sweetening.
I'll be checking the soil again a little closer to fall. I think I might take you with me on field trip to have the soil "officially" tested before making fall amendments. See you again with a soil post then.