Chris: What you describe sounds like a problem we had when we moved into our house and started planting outdoor plants. We planted new plants in a area not planted by the previous owner and shortly there after the yellow blotches and stunted growth would occur. When I took some leaves to our local very reputable nursery the man took one look and asked if any herbacide had been used on the ground or in the area. I was not sure but it was very possible given the low maintenance {lots of ginger stone ground cover} the previous owners installed. I'm sure they doused all open ground with Triox or some other long term herbacide. Anyway after about three years we no longer had the problem and none of our plants show the chlorotic symptoms they once did so I am sure that the problem was herbacide residue. I don't know about your case but its something to think about. Maybe someone was spraying weeds in your area. Take care and its going to be a glorious pumpkin year here in No. Cal. Mark Pleasanton