Hello, everyone. This is my first post. In fact, this is the first time I've joined a social networking site. I've refused dozens of requests from friends around the world to join Facebook, etc. and instead I join a group focused on worms. I can just imagine what my friends will say. :-)
I've been inspired to attempt a DIY Flow Through (FT) bin after reading the hundreds of posts in the multiple "My flow through bins" threads. Thanks to everyone who documented their experiences...entertaining & informative. I've incorporated many of the principles I gathered from you all. That said, this is definitely a work in progress and I would appreciate any input & suggestions. It's possible I'm missing something very obvious and I don't want to have unhappy worms.
Like others, I wanted to use material I had lying around. The major items I had available were a junky old wardrobe and some clear storage bins. I'll put the clear bins in the wardrobe to provide a dark environment for the worms. The clear bins would allow me to check on the progress of the worms & condition of the compost without actually physically disturbing the worms (aside from a bit of light). Here are some photos. My construction skills are minimal, so please don't expect to see anything like Eve's high-tech bin.
Basic setup: I lined an old photographic developing tray with black plastic and built a framework around it with wood from a pallet. The bamboo sections (~1" diameter, trimmed from my 'grove') aren't perfectly straight, so I just eyeballed their alignment & nailed them in place. The gaps are ~2.5". My impression was that people regretted making small gaps.
Here's how the grating appears looking down into the bin through the cut out bottom.
I used 4 layers of newsprint to cover the grating and 4" up all sides of the bin before adding 3" of almost finished compost harvested from my regular compost bin (CB). I placed 2 plastic bottles with the bottoms cut out and holes drilled all around as "chimneys" for added ventilation. I can stack another bottle on top or I may simply pull the bottles upwards as the compost level rises. This may be overkill since FTs are known for good airflow. But since the bins will be inside a wardrobe, I thought I'd add this feature. The bottles are easily removed if the system dries out too easily.
Next I transferred all the contents of a 2 week old storage bin wormery (bedding, worms & food). I will cover all this with a wet, thin cotton sheet (cut up t-shirt) to discourage fruit flies.
Here's a close up of the viewing side. I put some choice food flush against the viewing side to attract the worms to where I can watch them. They react to the flashlight beam, so I get to see them squirm a little. I can also see the tunnels they create in the compost - reminds me of an ant farm I had as a kid.
The complete set up with the 2nd bin temporarily perched on top. When the first bin is nearly full, I will use dabs of superglue and clear duct tape to attach the 2nd bin.
Each 66 qt. bin holds approx. 2.5 cu. ft. with 2.3 sq. ft of surface area. The grating and collection area in this setup is external to the bin, so the entire capacity of each bin module is available for composting. A 2 bin setup will hold 5 cu. ft. and provide 28" of vertical depth. I read somewhere that ideally you would harvest when the compost depth is 24", so 2 bins seems like it would work as long as I feed at an appropriate rate. I could add a 3rd bin to push the volume to 7.5 cu. ft. with a 42" depth. Hopefully that won't be necessary.