Lorraine, a PhD candidate at a local university has been taking soil samples from our garden for her research.
Her research is ongoing, but today, she sent me this info:
"What I can tell you is that the soil seems to be lacking in organic matter (the soil outside your garden has more organic matter than that in your plots) so you should work in more compost and mulch, and that all of the soils have a neutral pH. Neutral is best for plant uptake of minerals."
Great information. If you want more organic matter, make sure to work in lots of compost.