Ask-a-Dave's-Gardener: Garden worms, 1 by Pistil

Pistil wrote:
Hi valal-
I doubt you need to 'seed' your soil with worms, as the few that are already there will be happy to provide plenty of offspring, once they have an acceptable habitat provided. My evidence:

1-When I moved into my house, it had never been gardened, prior owners being quite uninterested in the yard. Areas I wanted to use for gardening had bad compacted clay and builders rubble, hardly any worms. I did not follow 'the rules' (digging in compost and amending soil) I just got rid of grass and weeds, planted (holes had to be chopped out with a mattock), and started sporadically mulching. It was an amazing transformation in just a year. One especially bad area now had soft soil I could scoop up with a trowel, and suddenly had tons of happy worms, where before I had found none at all. This spot is surrounded by pavement. Worms multiplied anyway. Photo below taken this May.

2- Last year I made two new gardens. These I had a 'planting' mix trucked in. I spread 6" on top of the bare earth, and planted in that, then spread about 1-2" mulch. Of course there was initially not a worm in this stuff, and the soil below where there was lawn (killed with a layers of newspapers or cardboard but not dug up at all, and no worms seen in the crappy compacted soil). This year there are zillions.

3- I have an area on concrete by my garage where windblown leaves collect. I am somewhat neglectful, and usually only clean it up about twice a year. If I do it every 2-3 months I see no worms there, but if I leave it about 6 months I am scooping up humusy decomposed leaves with, again, lots of little baby worms. This stuff seems like fine compost to me, and I place it in my garden. I don't even know how these worm eggs even get in there, possibly birds?