I used to raise them when I was in Jr. High school. I built a wooden box frame without a bottom about 10 inches high and filled it with dirt and commercial worm bedding and put it in my basement which had a ground floor. I caught night crawlers and put them in the box and put in coffee grounds and some organic material, chopped vegetables, lettuce and carrot tops etc and mixed in into the earth and bedding. I had good success, I was selling them worms to fishermen all over time. They were reproducing but I still had to continent to catch new ones because of the number I was selling.
When you are up to your butt in alligators, it is hard to remember your intent was to drain the swamp. Stay focused!