Beans for soil enrichment?
In order to enrich my soil with additional Nitrogen, I am thinking of growing some beans. My question is:
Do I wait until the beans are past eating stage (straggly and dry) and then just cut them off at the surface, leaving the roots in the soil, or:
Do I dig up the whole plant after growing season, or:
I have not grown beans in this soil before and it is quite clay with only a few inches (about 6) above the clay.