JD wrote:
Location - South Central Kentucky

This is a recurring problem every year. I'm not sure, but neighbors
claim it is some sort of blight. When the humidity of summer finally
sets in, my tomato plants start turning yellow from the bottom up
[...]


I had a problem this year with some plants that I was very late
transplanting. Since they were very tall I decided to bury them extra
deep. For whatever reason they are doing very poorly with many turning
yellow.

Dave in STL