Four pounds of worms would occupy four square feet of surface area.

Night crawlers are not a good composting worm because they tend to live in deep burrows. The most suggested composting worm is a red worm with the scientific name of Eisenia andrei.

In good conditions Eisenia andrei can compost half their weight per day. You do loose volume due to evaporation.

Vermicastings contain enhanced micro nutrient availability, plant growth regulators and beneficial microorganisms.

I believe that partially composted material(taken past the heating stage) would be better for worms than completely composted material. The bedding is part of the worms diet too.

welcome to world of worming!!! I have just started as well..about a month or so ago.

You can use Eisenia fetida worms as well. I use them myself and find them to be 100%.

I started with a less than a pound...but I must say that if you can get more you should.

And regarding the bedding. I am thinking about using well aged and semi composted horse manure for bedding mixed with some shredded newspaper. Maybe some of the other forum members can give some more advice regarding this.

How many worms?:
1. You don't need to get the number of worms at the start that you are ultimately going to want to have. They reproduce pretty quickly. They sort of expand to fill the space available.
2. Although your local nightcrawlers are not right for vermicomposting, you probably can get some of the right kind if you want to try that. You might visit someone's manure pile, for example. There are some ideas on this forum about leaving damp cardboard in the woods for a couple of days, for another example.
3. Check out www.vermicomposters.com. There is a map of people who have worm bins, and a recently started feature of this website is a key to people who have worms they would be willing to share with you. It's a kinda new website, and there are only a few hundred people on it so far, but you might luck out.
4. Another suggestion is to look on craigslist for people in your area who have worms to sell, or even to give away. Freecycle is another place you may be able to find them. For free!
5. You can also buy them from dealers of course, and you can find on this forum some information on dealers people have had good luck with. Also on the vermicomposters website.
Good luck, and have a good time with your worms, once you get them. They are great little contributors to our lives and gardens!
mbetts

Thanks for the info everyone! You've been very helpful.