often done in the fall to be grown until spring, or sometimes interplanted among food plants such as in an orchard. a cover crop creates air in the soil when the roots grow and die, grow and die again. sometimes a specific crop that's especially good at breaking up hardpans is used, such as certain radishes...
others, need conditions cooler than c. some seeds will only germinate after hot temperatures during a forest fire which cracks their seed coats; this is a type of physical dormancy. most common annual vegetables have optimal germination temperatures between - f ( - c), though many species (e.g. radishes...
thanks for the great site. john reply phil on august , at : pm good question. if you literally can't get your shovel in an inch, i'm not sure those radishes will get very far either. sounds like you need to send a soil sample to a good organic lab and then balance out the soil nutrients, as well as improve...