Hi, I have had this happen not only to my pole beans but also to the lower leaves of my edamame and tomatoes. The lowest leaves get yellowed and the leaves in general don't stay dark green. They get more of a pale green. Could I be over or under watering? The soil is definitely more clay than it needs to be, but other veggies grow fine and I don't think the beans need to go very deep, right? Suggestions?