I was asked to write up a how to for my vermicomposter and I was also asked for blue prints so I figured I'd do a complete write up.
After doing a LOT of research about vermicomposting. (Starting with Rev's book "True Living Organics") I quickly realized that "commercial" worm farms are very expensive and really are quite simple. I did a bunch of further research and found out people are doing worm composting very effectively in really AWFUL worm farms made in cardboard boxes, foam coolers and lord knows what else. I decided I could do better for cheaper and I was totally right!
First I bought three "Rubbermaid Roughneck" 10 gallon heavy plastic totes with lids. Mine cost me $6.00 each at Wal-Mart .I'm sure they can be had cheaper but I wanted known quality and these ones were an almost ideal gray colour. (Black is ideal).
I purchased my spigot, washers and nuts for securing the spigot at Home depot for less than $10.00 total.
The spigot is a "1/2 inch boiler drain"
I used moen brand faucet lock nuts
and bought an assortment of rubber o-rings to use as washers.
To build the bottom tray (Which MUST be waterproof) I used my electric drill to drill a 1/2 inch hole as low on the first bin as I could while still being confident that I could thread the nuts onto the spigot. I applied a liberal amount of aquarium sealant on both sides of the hole just to make sure I had no leakage EVER. Once the aquarium sealant was tacky I threaded a nut onto the spigot, followed by an o-ring then I threaded the spigot through the hole. Once the spigot was snug against the plastic bin I added an o-ring to the inside and then the second nut which I tightened as tight as I was comfortable making the bin completely water tight. (I filled it with water overnight and had no leakage). I know it's ugly but Aquarium sealant should be food safe.
The other two trays are even simpler I stacked them just like they'll be when they're in the composter and I drilled a series of 1/4 inch holes around the lowest point in the bins so that the worm tea can leak down into the bottom tray and so that the worms can move back and forth bewteen the containers. It is important to understand that you can overdo it with the holes. The tea and worms only need about 8-10 holes to do their jobs effectively. I put in a few more holes but only because I'm using such big bins I wanted to make sure the trays had good bottom aeration.
Once you've done that your worm farm is essentially built. The next step is sourcing worms. The best place to buy them from in Ontario where I live is a place called Cathy's crawling composters. (they ship anywhere next day for cheap). For a farm this size you'll probably want a pound of worms. (Red wigglers only. Other worms will work but not nearly as well or as quickly)
My bottom tray got a layer of newspaper (black and white ink only no glossy paper). Then I added 4 cups of potting soil and perlite. (About 2-1) On top of the potting soil goes 2 pounds of worm food finely chopped and of course your pound of worms. (Best way is food at one end worms at the other. Worms are very light phobic so if you do this step in as bright an environment as possible you'll prompt them to dig in and get to work right away.)
The third bin goes in on top and has it's lid firmly attached. Your worm food goes into the middle bin until it is about 2/3rds full of castings at which point you start feeding the worm food into the top bin. As the worms run out of food in the middle bin they will naturally migrate into the top bin leaving you with fresh castings in the middle bin. Once the majority of the worms have migrated you simply empty the bottom bin into your soil mix storage and it becomes your top bin with the lid firmly snapped on. If you keep up on your system weekly you'll always have fresh castings, probably more than you know what to do with. Fortunately they go great on your lawn, in your flower beds and wherever else anything grows.
The worm food recipe I plan to use comes out of the "Total living organics" book and is as follows.
Worm food
Start with about 2 gallons of moist food scraps
Add the following every other time you feed or so (In addition to the 2 gallons of moist scraps)
4 cups perlite
1-2 cups of well-rinsed coconut coir
1 tablespoon greensand
2 tablespoons crushed or ground oyster shell
1 tablespoon granular rock phosphate
1/4 cup all organic alfalfa pellets
2 tablespoons kelp
2 tablespoons humate (Humic acid ore shale)
Plenty of dried and shredded cannabis leaves, stems and roots
2 cups shredded junk mail/paper
