About three months ago I dug out the sandy soil on the north side of my shop. Put in 2X10 treated lumber 30" wide by 10 ft long about 30" deep filled it with mulch I got at the land fill. Two weeks ago I put 3" of rabbit poop on top turner it in a little with the mulch. This morning I turned the soil over and I have 1000's of worms. Don't know they came frome but they are there.