Nasturtiums love poor soil! And they aren't all the trailing kind. In fact, if you add too much good stuff to the soil, nasturtiums don't do well.

I didn't notice that they smelled stinky

What zone are you in? Are you looking for just flowering plants, or veggies and shrubs too? By garden plot, I'm guessing you aren't talking about "landscaping"?

If you can't have a compost pile, how about adding your kitchen waste by first putting it in the blender, adding water, and then watering your plants with that. You will get some 'fiber' from the bits that don't blend so it will add some structure to your soil too. Use the grass clippings, (if you don't use chemical in your lawn that is) as a side dressing to your plants, just stir them in each time you cut the grass.

You can also used shredded up paper from your junk mail to the grass clippings and cover that with the soil. It will break down within the gardening/growing season quite well. It helps keep moisture in.

As to what to plant, I don't know! What does your local nursery sell? Usually that is what grows well in your area. Then account for the filtered/shady area and go from there. I'd also try things with long deep roots, as that sort of plant brings up soil nutrition that short rooted plants don't.