An email conversation prompted me to make this post. It turns out keeping a thriving worm bin is a bit tricky. I’m learning as I go. This is only what I know so far.
I got my setup from BWCN Farms (I have no idea what the initials stand for). My first batch of African night crawlers died in a freeze last October. I bought a new batch of worms — this time red wigglers — this April. John at BWCN was very patient with my hand-wringing and insecurity.
Here’s how I start a new tray. First off, I mix equal parts (1 scant shovel full each) of dirt and leaf compost. To this I add shredded newspaper and a crumbled egg carton (or other cardboard source). I put the paper goods in a gallon bin and add about a pint of water and slosh it around to make sure the paper soaks up the water.
I stir it all up in the wheel barrel. I add water if it’s needed.

I keep on pulling the newspaper apart and mushing it up with the leaf/dirt mix. I need to provide a source of roughage (sand or egg shells) in the mix. The worms ingest this and use it to grind up what they eat.
I save my egg shells in a custard cup until it’s full.

When I have enough I pulverize the shells on a breadboard using the bottom of the cup to grind them up. Some of these pieces are too big, but most will do.

Since I’m adding a new tray to an existing setup I need to remove the top layers of solid newsprint so the worms can crawl between the old bin and the new one that will go on top. (These bins have mesh bottoms to allow for drainage and worm transit.) I’ll put the solid newspaper back on top of the new ‘top’ tray. This keeps flies out.

Here’s a look at happy worms in their ‘old’ tray (only 1 month old). Bits of the green can be seen where food was placed. It’s a good sign that worms are in the green stuff. I just sit the new tray right on top of this.

I only put in about a pint of chopped veggies about every 5 days or so. Usually I freeze the veggies overnight to help break down their cell structure. My worms just aren’t big eaters. Either that or they’re busy “eating” the newspaper and cardboard.
I was told that the most common mistake folks make is putting too much food in the bins. So I check to see that they’ve eaten what I gave them previously before I add more food. Clearly most of my kitchen scraps get composted outdoors.
My worm bin has never smelled and if the top tray is properly covered with solid wet newspaper and the bin lid it won’t get flies either. Last summer when the temps were in the high 90’s I actually brought the worm bin indoors.
I don’t have a picture, but finished worm casings have an unmistakable “coffee grounds” texture. (You can already detect that texture developing in the last photo.) Now that my worms have multiplied, I harvest the worm casings about every 3 – 4 months. It’s in constant flux as the population and seasons change.
So why do this at all? Good question! I guess mostly it’s very fast. The worm casings can be put directly into potting soil (whereas compost has to cure first). I guess another reason is the worms themselves. If you need to add some “biological action” to your soil these guys will do it.