What's wrong with my seedlings??

Hello plant people,

I have four yellowhorn seedlings that are not doing well. I bought 10 seeds, and have 4 other yellowhorn babies that I planted earlier in the year, and they're doing fantastically. These guys were planted into a different potting mix, and have been struggling with life from day 1. Any time they send a shoot up, it ends up shriveling and drying up within days. Then the nut sends another shoot, which also shrivels up and dies. It's been weeks now, on repeat, and it's painful to watch. I moved them into new pots with new mix after a couple of weeks, but it's not getting better at all...

Any ideas?

Oh how sad! I have not grown yellowhorn, but I will ask you the same questions I ask myself when germinating out my garden.
1. What temperature are you starting them at? Most seedlings want about 70, but some (like okra) don't do well under 80 degrees, and some, like radishes want like 50 degrees. Wrong temp promotes diseases like wilts.
2. How good were the seeds? older or deformed seeds have funky seedlings.
3. What pH does it like, what pH is your start mix?
4. I see some what looks like salt build up on the mix surface. That can mess things up. Replacing the mix (as you say you've done) might help, but also check your water. Perhaps use rainwater or make sure you flush the irrigation water good when you do water to avoid salt build up. Along those lines, some people will let water sit 24 hours to reduce chlorination in their water. I wonder if letting your water sit and skimming off the top won't reduce your mineral load to the plant.

That's usually what I watch. I hope that helps!

Been a while since the post (oops). I ended up digging these guys up, rinsing the roots, and planting in brand new soil. I guess must be some critters in the previous soil that were probably attacking the roots. They've been way better since. Still not a picture of total health, but the one plant I left in the old soil died, whereas the three I replanted are recovering.

Really frustrating - it's my third year gardening, and it feels like the diseases are really cropping up this year...