New plants not growing

first time grow here, and i gots a problem.
I planted 15 seeds into individual red cups and stuck them outside. All of them germinated fine btw.
anyways, i planted them a week ago
right now, only 1 of them has any leaves, 3 of them have a little stem thing that lays flat, and i got nothing from the others none of them have gotten any bigger since about 4 days ago.
Why'd they stop growing?

post some pics they help out a lot

eh. i dont think its important, i think the seeds died for some reason. so ill be trying again soon, this time im going to start them inside.