Picture of Self-Harvesting Vermi-Compost Bin
Below is a design for a "self-harvesting" vermi-compost bin. 

The materials were sourced from recycled lumber and fencing. The only purchased item was a metal shank used for the "slicing" action that we will see later on.

Materials needed:

• Skill saw/Jig saw
• about 16 ft. of (depending on how big you want it)  2x12's
• box of 1.5 inch screws
• 4 foot steel shank
• something that can bore a hole in metal...preferably fixed drill-press.
• 4 2x4's cut to 3 ft. each (legs) 
• 2 2x4's for corner bracing + leg support
• Deer Fencing (12ft area - two sheets)
• Staple Gun
• Siding/Lath

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Step 1: Measure and Cut

Picture of Measure and Cut
Cut your 2x12's into 4- 4ft pieces + 4- 3ft pieces (3ft piece below)

Cut a rough estimate for your deer fencing (the bottom area of your 4X3 bin) will need to modify the fence as you apply it to allow the bin-legs to fit through.

Step 2: Brace corners

Picture of Brace corners
Split some of your 2x4's to brace the corners of your freshly constructed bin skeleton. 
This also allows your 2x4 legs something to sink into....

Step 3: Apply "Netting"

Picture of Apply
Overlap two pieces of your deer netting (staggered) to reduce the size of fencing holes. (this prevents your vermi-compost from falling through before you are ready to harvest it.

If you have a staple gun handy, secure the edges of the fencing against your wood frame...otherwise you can wait until step 5. 

Step 4: Legs

Picture of Legs
In order for the vermi-compost to drop it needs to be raised. Cut your 2x4's to anywhere 2-4 ft. to allow for easy inspection of underlying vermi-compost. 

Drill 2x4's into raised bracing + larger wood frame (angle). I choose to place the legs ontop of the fencing to ensure added support for the weight of the compost. 

Step 5: Fencing Bracing

Picture of Fencing Bracing
Add your lath now. 

Drill a good number of screws (4-6 on the 4ft side / 3-4 on the 3ft side) to ensure strong support of fencing.
I decided to double up my layers on the 4ft side just in case. 

Great idea! Nice pictures!
AnnaLove2 years ago
I love this, my household has three vegans and we have soooo many fabulous kitchen scraps - melon rinds, banana peels, pineapple outsides, juicing pulp, etc. Easily a whole brown grocery bag filled up every day. I've been tossing it all into the city compost/yard waste bin and it's such a waste. Thanks for this 'ible, it's the first non dump-and-sort worm composer with a huge capacity I've found.

Just wondering, how smoothly does the "slicer" slice? If the bin is really full and heavy does it become difficult to move or does the compost just crumble out? Also, does the open bottom allow the compost and worms to dry out much?

Thank you!
skyssa (author)  AnnaLove2 years ago
We have modified the design since. We are currently using two welded winding mechanisms that are attached to rot resistant industrial strapping that pulls the a hank through. It is geared, so it greatly reduces the amount of energy required as the bin fills up. Our system is on the west coast (currently in Iowa) so it will be a while until I can get another set of pictures.

The lower inch or so dries out if you leave it to long (which is not a bad thing, as it forms a protective crust preventing further dehydration of the rest of the vermi-compost)
wllmundrwd4 years ago
Alright, what is that blue vehicle...? Looks very interesting.
skyssa (author)  wllmundrwd4 years ago
Electric Car :) Two seater.
boxofish4 years ago
Looks interesting but doesn't the shank chop up alot of the unfortunate worms that might be loligaggin' around down at the bottom? Also, I'd love to see a video in action. Otherwise it's a very interesting idea, good job!
skyssa (author)  boxofish4 years ago
Nah, the Worms move towards the top of the bin because of the organic matter that is constantly added to the bin. They always "sniff" out the decaying material... This uses the same mechanics as most worm bins only it has the added benefit of "slicer" to cut down on sifting through and picking out the good compost vs banana peels :)

I'll post a video once we have a enough worms to fill this beast... our eyes were a bit bigger than our current capacity.