Cover crop for clay soil - please advise
I live in Medford, Oregon and have non-homongenous soil (dense clay with partial loam). Nitrogen, Calcium, Magnesium, Sulfer and Copper contents are low. I thought to cut back the lawn and plant Diakon radishes and Fava Beans to prepare soil for a border of perennials, conifers, Maples and shrubs. The lawn is getting cut back at end of next week which means I could possibly begin planting mid May. Have I missed the planting time? Should I wait until Fall? Is there something else I could use?
I did have a soil test done but the recommendation was just an application of compost and organic fertilizer - I think I need more to whip this clay into shape. Yes?