Hello Doctor & welcome to GOY.
I grow Morning glory from seed and I feel that you may have planted the seeds a touch early.
I normally wait until May to plant seeds and once they are up and running, about 3-4 ins, I plant them out.
I feel that the ones you have now will bolt a little and its too early to plant out. ( Frost ).
You could get them going up a mini trellis indoors I suppose, but personally I would sow more seeds in May. They are very fast growers, just keep the snails and slugs off them. Good luck.
Like the avatar BTW.

I'd pot them one when they get roots coming out the bottom of the pots. They may need support . during the milder days I'd also put them outside and bring them in on a night.

Thanks Seaburngirl and Littlelegs.

The survivors and their flowers may have been few (best one day was 18), but they can't help being beautiful during those too few hours when they are open.

Next year I'll follow your advice, with my fingers (not green, alas) crossed. And I'll stick to Star of Yalta.