I planted my tomatoes 4 days ago and did not leave them out to harden first. The first night got down to 44 (NC zone 7)but I covered them with milk jugs (with bottoms cut out). I have noticed spots on some. I have 7 tomato plants and they are all different and bought at different hardware stores and a farmers market. The spots have shown on some, not all. Is this due to the stress of transplanting and the cool weather that first night? Or is it desease?