Something about the idea of raising worms has always appealed to me. And it has never worked out when I've tried to do it.
I have a plastic worm bin type of thing. It has three levels of bins, each with a bunch of small square holes in the bottom. And a top that sheds water. Basically what you do is load each bin with dirt and worms and and once in a while add some groceries. Pretty soon you're supposed to have a gazillion worms.
Next to last time I tried this the worms all died, from the summer heat I suspect. This last time I ended up just turning the worms loose.
I had the three bins loaded with potting soil from a bag I bought at the nursery. Miracle Grow brand. I loaded the potting soil, then loaded the bins with Canadian Night Crawlers that I bought from an on-line source. I fed them about every three days - a combination of bread crumbs and coffee grounds.
After about two weeks I went to feed them and when I opened the first layer (newspaper cover over it to help maintain moisture) I found all the worms on the surface over to one side, while in the middle it was heaving with large brown maggots.
Each of the three layer were the same. The worms were trying to stay away from the maggots and I'm pretty sure there were fewer worms. Perhaps the maggots were eating the worms, looked like it. Having looked these maggots up on the internet they appeared to be an insect called a Soldier Fly. These do not appear to be native to this area, but they may be as they look quite a bit like a dirt dauber when in their flying stage, so who knows...
But I didn't see any point in raising soldier flys on my worms so I dumped the worm bins in a shaded and leaf covered area. That way the worms could escape from the maggots and I hoped the maggots will quickly dry out and die. I'll check sometime later today and if there are still maggots I'll rake them around with a rake to expose them to the elements.
I don't know if the maggots came in the potting soil or if these insects are already in this area and infected the bin, or if they came with the worms.
I'm thinking of maybe trying again some day, but this time with soil I dig up from my yard, and only after I figure out some way to put screening on/over/around the worm bin to keep any more of the maggot causing infestators out.
Meanwhile I'll continue to buy worms when I need them. They keep forever in the refrigerator where my wife is happy to put them.