yes castings are an amendment, they are primarily beneficial for the high bacterial population and humus-y nature of the nutrients, very gentle and slow acting but rich

soil bacteria is what it's all about - that's what the worms actually consume, that's what converts the organic nutrients in your garden to the mineral nutrients the plants use, as the plants need them and in a balance conducive to healthy plants

castings might be considered 'poo' but aren't really comparable to animal manures - castings are an organic material high in microbial life, and the worms can live well re-ingesting them for a long time - they have very inefficient digestive systems

the castings are harvested any old way you can seperate [most of] the worms from the processed material that is no longer recognizeable as the feedstock material ... the trash can bin you mention is "self harvesting", with the finished material coming out the bottom thru the bars - might work for some folks, but you're better to start with the usual Rubbermaid tub .... all you need to start is the tub, filled with some bedding like shredded paper and cardboard, some kitchen waste to feed, and some worms

you're best off to get a bin set up and material microbially decomposing before adding the worms, so they immediately have some good stuff to slurp and don't wander away looking for better digs - also needs to be quite moist, well ventilated, and preferably with a lid to keep it dark so they can surface if they please

Bill

I'll second Bill. (He does seem to be one of the real experts here!) Start with a smaller bin, get used to them and then move up to the trash can. That way you can make the rookie mistakes we all make in a more easily controlled environment (you can easily get to the bottom and see what's going on without ruining the whole thing.) I'm hoping to move up to that when my herd is big enough. I started with 3 oz of worms in January, I have well over a pound now, but as much as I want to know how many I have, I don't want to disturb them enough to separate and weigh them. I'd rather leave them to eat and make more babies!
Just to be sure you know, you won't get any product for a number of months. For me (with so few worms in the beginning), it was 4 months and even then there wasn't much. My second harvest last month was very substantial. Also, even though it's rotting food and worm poop, it truly doesn't smell unless you let it get anaerobic - in which case it's horrid, but it's easy to fix and to avoid. I think we all have that problem once as rookies.

Bill said "get a bin set up and material microbially decomposing before adding the worms" -> I'm expecting delivery of my can-o-worms and the worms next week, so would it be a good idea to start collecting food for them now, not refrigerating it so it starts to decompose?

Thanks
Chilli

Right! Collect the food scraps and put them in your bin now, along with some bedding materials. It would be a good idea to chop up the peelings, etc. You don't have to puree them or anything, just cut everything up into pieces. Throw in a handful of dirt too. Your worms should feel right at home when they do arrive.
MB

I wouldn't worry too much about collecting food now for worms that are on their way. One of the most common rookie mistakes if overfeeding and over watering their worms. When you first start a worm bin, the first several feedings need to be really small and you need to wait till most of the previous feed is gone before feeding again. Moist corrugated cardboard makes great worm bedding and it also has some feed value unlike most other bedding materials. Be careful to keep the worm bin only slightly moist since each time you add food, it adds moisture. To keep things from getting too wet, keep dry bedding on hand to mix in whenever it seems to be getting too mucky. If the very top of the bedding drys out, don't worry to much about it so long as the bedding down below is still moist.

My worm bins are wood and so breath better than plastic bins. Any sort of container usually makes a fine worm bin. The trick is providing enough air, moisture, bedding, dark and some food and the worms are happy.

Here is a link that might be useful: TCLynx