To keep a worm bin outside would involve insulating it somehow, or having it open to the ground so the worms could crawl down and not freeze in the winter. This seemed a) complicated and b) like it would be unsuccessful because it would involve me going outside to put the scraps in, and I'm pretty lazy.
1) I went to Target and got two Rubbermaid Roughneck storage tubs, 10 gallon size. The dimensions are 23.9 x 15.9 x 8.7 inches. I read in more than one place that the tubs should be at least 12 inches deep, but these were the deepest I could find that would still fit under my sink.
2) I left one of the lids intact, and drilled lots of little holes in the other lid so the worms can breathe. These holes are not big enough for the worms to get out of. You can barely see them in the picture, but I made a pretty star pattern on the lid.
3) I turned both of the bins themselves over and drilled bigger holes in the bottom of each one. I tried to make the diameter of these holes around 1/4 inch, which is big enough for the worms to crawl through. I didn't actually have a drill bit this big, so the holes turned out not to be perfectly round. The purpose of these holes is twofold: to let the liquid drip out of the bin, and to allow the worms to crawl into the other bin when it's time to harvest the castings.
4) I read in several places that the best thing to use for bedding is damp black and white newspaper pages, cut into 1 inch strips. I don't get the newspaper, and I thought to myself, "it's not like worms can only live in newspaper bedding out in the wild," so I actually started by using old leaf matter for bedding. I went out to my yard and gathered up the stuff that I should have raked last fall (see, procrastination can be a good thing!), wet it down with water from the sink, then put it in one of the bins. I think you're supposed to have about 6-8 inches of bedding at any given time, so this picture actually doesn't show quite enough bedding in the bin.Lately, I've started making the worm bin into a paper recycling bin as well, emptying my dad's shredder, wetting down the little strips, and using them as bedding. This actually seems to work pretty well.
5) The final step for setup involves putting it together and adding the worms. I took the intact lid, and set the bin with bedding on top of it (the lip of the lid serves to hold the liquid that drains out). Worms went in -- I was lucky enough to be able to get some from the worm bin at the school where I teach, so I didn't actually have to buy them -- and I put the lid with airholes on top of the bin. It fits really neatly under the sink. (I considered linking to some sites where you can buy red wigglers, which are the type of worm you'll want to use for vermicomposting, but since I've never used any of them and can't vouch for their service or reliability, you'll just have to google.)
6) I have a little container that sits on my counter and I just put the appropriate food waste (basically no meat or dairy, any fruit, veggie, grain scraps are fine) into the container and then when it's full, I empty it into the bin. I haven't cut scraps into 1 inch pieces like I think you're supposed to, and it works fine anyway. I use a big kitchen spoon to stir the scraps under the bedding and mix them in with the nice dark organic stuff on the bottom of the bin.
7) Whenever I feed the worms, I drain the liquid in the bottom lid into the same little container. This "worm tea" is supposedly really rich in nutrients, so I either pour it on my plants, or send the boys over to my mom's with it, so she can pour it on her garden.
The whole feeding process takes less than 5 minutes a couple of times a week. The only bad part is that (as you can see from the photo above) that the length of the bin is wider than the cabinet door, so if I'm not careful about how I take the bin out of the cabinet, I end up getting worm tea on the floor. The bin itself doesn't smell at all, and you would never know I'm composting in the kitchen (even when the lid is off it just smells good and earthy, not at all like all the rotting food that's in there) but the liquid is pretty smelly so I'd rather not have it all over my kitchen.
Worms can be poisoned by their own castings, so after 2-3 months, you are supposed to harvest the castings. This setup seemed like the simplest diy harvesting method out there.
8) When it's time, I'll take the lid off the bin I'm using, put bedding in the second bin, set the second bin on top of the current bin, put the lid on that top bin, and start feeding the top bin. The worms will crawl up through the holes in the bottom of the top bin, and when they have evacuated the bottom bin, I can remove that, use the compost, rinse it out, and it will be free to serve as the second bin when it's time to harvest again. Nice, huh?
Worm composting is fun and easy!
(Dante took these last two pictures while I was drilling -- apparently he thought I just wanted cute pictures of myself leaning sideways?? and didn't realize that the point was to show the drilling and the bin! He did do a good job of taking all the other pics in this post that have me in them -- and threw in the bonus one of Sebastian while I was pouring the worm tea!)
The New York City Compost Project has some good general composting info, as well as detailed information about vermicomposting. Another worm bin how-to(very similar to mine, but different enough that it might be worth a look) plus troubleshooting ideas and a list of what can be composted in your bin can be found here. If you've got kids who want to read up on the topic or build a bin themselves, try this link. If you feel like my plan is too simple and you want to use rubbermaid tubs to make a more complicated bin, click here.