Funny you should mention that. I was just thinking about transforming areas in my city back yard into a sustainable garden and wanted to ensure that I kept it organic. I think getting earthworms back in there after years of pesticides is a great idea and I'm going to look into it!
That sounds awesome, earth worms favorite food is horse manure and with the help from a worm factory most of the work is done for you.
All you have to do is add manure and rotate the bins as the earth worms crawl up to the next levels as they finish the manure in each tray. Here is a link to my favorite earth worm web site where you can find the worm factory http://www.wormswrangler.com/?gclid=CPDK5aDZpZgCFREeDQodRXBAng
Many years ago on our farm in New Brunswick,one of my "chores" was to feed the worms we raised in the basement.....they loved horse manure.......and then the castings were used in our vegetable garden.The plan was to have them multiply enough in numbers to compost all of our manure before we spread it on the land.