One way to kick-start peas is to soak them in room-temperature water for an hour, then keep them damp overnight before planting. That gets them past the germination stage, and they can handle the cooler soil temps after that.
I am thinking now that it is the Fusariium wilt. What I read was that they are susceptible, and the fungus gets going once the temps are 70 degrees. That kinda fits the time frame for when they start going down hill.
I am planning a two prong approach. Sprouting the peas(even earlier next year, so they get some good growth before transplanting) and planting the short DTM in the beds, and the longer DTM in a container of potting mix.
Like I said, I really don't like peas that much, but they are nutritious for humans, and help fix nitrogen in the garden. They are supposed to be easy to grow, so I am perturbed that I have not yet successfully grown them.LOL