1) No. The worms you find on the sidewalk are not the same worms used in vermicomposting. Besides, worms have their own methods for replenishing their population.

2) No. Worms will regulate their own population.

3) Maybe. If you already have a healthy worm population in the soil, some people will advocate simply building a compost pile, mulching heavily with organic mulch, or building an outdoor worm bin and letting the worms come. A worm bin is a controlled environment that runs more efficiently than the worms that now live in your soil, but on a much smaller scale.

One thing to consider is where, exactly, the worms in your soil live. Are they deep burrowing worms, horizontal borrowing worms or litter dwelling worms? Litter dwelling worms are the most efficient composters. Having a bin of litter dwelling worms to supplement the efforts of deep burrowing or horizontal burrowing worms may be a good thing.

Thank you very much for your orderly answers. All my beds have been amended and they get mulched yearly. I will read up on whether I have deep, horizontal or litter dwelling. I suspect I hv all 3, my soil is quite wormy, lol.