Self-Harvesting Vermi-Compost Bin

Intro: 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

STEP 1: 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)...you will need to modify the fence as you apply it to allow the bin-legs to fit through.

STEP 2: 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"

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

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

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. 

STEP 6: "Slider"

Next, use a skill saw (or, if you can't find one... a jig saw) and saw a half inch slit on the 2 inch mark of the bottom of your siding. 

Do this on both sides until you can comfortably slide your metal shank from side of the bin to the other.

*note - make sure, if you're using the jig saw, to drill a hole first with a sizable drill bit in order to fit the jig into the wood in the first place. Ideally, use a skill saw.

STEP 7: Touch-ups

Now that your "cutter" is in place - you can bore two holes on either side of the metal shank and attach a piece of rope in a loop over the wood frame so that one person can pull the loop of rope and slide the entire shank through. 

For covering... 
use a thin piece of wood or whatever else you have lying around that will sufficiently block out sunlight. make sure to cut plenty of air holes in this thing (not too big...) so that it aids the bin in staying aerobic. 


Fun part....

Place a tray underneath and fill it up with worms+organic material. It's a good idea to put down a good amount of paper shreddings until the compost has created enough aggregate so that it won't just fall through the fencing.

 Once the bin starts to stack, the worms will constantly climb up towards fresh organic material and this is when you can start sliding the "slicer" and collect your fallen compost in your tray below. 

Enjoy!

Comments

[PierreL2]

Choose your netting to be able to carry the weight of the contents
A bin this size will weigh up to 600 kg
When filled to 61 cm ready to harvest
To be able to move the slider over the netting, the surface should be flat and the slider almost touching the netting
A bulging netting will scrape with difficulty

[margareth21]

Great idea! Nice pictures!

[AnnaLove]

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]

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)

[wllmundrwd]

Alright, what is that blue vehicle...? Looks very interesting.

[skyssa]

Electric Car :) Two seater.

[boxofish]

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]

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.