How do you breed nightcrawlers?

[Magnarock the 2nd]

I have over a dozen night crawlers that I have collected from the dirt patches in my yard. Im worried I will exhaust my yard if I keep collecting. How do you get these things to breed? I have them in a naturalistic plastic box with a layer of moist dirt and a top layer of damp leaves. They seem to like the leaves and they are strong and lively. Will they breed?

[guidofatherof5]

Check out YouTube for some videos on the subject. Search "Breeding night crawlers" or "Raising night crawlers"