Help! My brassica seedlings don't look good

I planted my brassicas Feb 23rd. They fully germinated by Feb 26th. It's now been a little over 2 weeks and I am only seeing a few with what looks like true leave buds. The cotyledons are starting to look dusky.

The stems have mostly since sprouting looked purplish. The temp is around 68. No signs of damping off. I've picked up a few of the "pots" and the roots have emerged through the bottom and there are roots growing out through the sides.


Should I pot up now even though the true leaves aren't out yet? I think the answer is yes because the roots are growing deep. For my other seedlings should I pot up sooner before I see true leaves so that this doesn't happen?

Thanks in advance for any advice.

Here's a pic of the roots:

I had my tomatoes in those pellets and I had to get them out of there before the true leaves came bc the roots were coming out of the bottom. They recovered well in MG potting soil in 7oz Dixie cups. I thought those pellets were so neat at first, I'm starting things in a city apt and trying to keep the footprint down, but I'll never use them again. It's only potting or seed starting mixes for me from now on unless I get ambitious in the fall and mix up a formula I've seen a lot of on DG before we close the house for the winter.

Good luck!

Pam