Sorry for the delayed response; I've been out of touch. Nope, no additional nutes in the starter mix. But, I failed to note that I am using those Jiffy pots. I've tried doing some research and can't seem to find any reason why these could be causing the problems. PH perhaps of the mix or pots?

The seedlings are not improving. The downward curl continues and they appear to be stunted. They just don't seem to be thriving as would be expected at this stage. It's about time to start on some nutes, so I'm hoping this will pull them out of their funk. Any other suggestions? I can't think of anything beyond the medium or the Jiffy pots that could be the culprit.