I'll be "that guy" and say the size of your container probably wasn't the problem. Here's some peppers I don't really care about that have been somewhat neglected growing in a tiny peat "puck". Poor lighting, no fertilizer, just good old tap water when I remember. Yes they're sunburned, yes they're covered with funk from the god forsaken cottonwood trees that surround me, and yes they aren't the finest looking seedlings and they should have been potted up but the point is they're alive and growing and they're doing it in a teeny tiny space.