I gave my son-in-law a "earthworm habitat" one year for his birthday. They were living lakeside and love to fish so thought he'd have continuous bait. It worked really well. I got a huge plastic pot from a local nursery - a pot that a tree would come in. I then dug a hole and sunk the pot into the ground. Filled it with dirt, compost, bagged soil, a little bit of everything I could find. Added some oatmeal and a splash of water to keep it slightly moist. Then bought a bunch of bait earthworms and threw them in and topped it with a garbage can lid to keep them from escaping. They lived and he had a continuous supply of bait the entire summer. He would feed them with some oatmeal, veggie scraps, etc. occasionally and made sure it didn't totally dry out.
They moved from that house the end of the summer so not sure how the worms did over the winter. I'm sure there's a "real" way to raise them, I was just going on what I observed and it worked for the time he needed them.
That is very cool. The good thing about the worm factory tray system is there are different levels, and I've been thinking of doing red worms on one level and earth worms on another. I'd just have to block them from traveling the separate trays.
Great gift for the fishermen in the family. My hubby ranted one day for an hour about the cost of night crawlers at walmart.