Stackable flow-through Vericomposter

Tool Concept

Primary problem statement:
I am a Agriculturalist and I want a tool to turn waste into worm castings because they can be a valuable input.
Read more about this problem statement


A year ago I built some portable, stackable vericomposter boxes that have been successful in raising red worms in central NC through all seasons. This project shows that vericomposting can be effective in a small space, with inexpensive and/or free materials, from easily obtainable materials.
Documentation Wiki: 

I wanted an easy to use, portable, light, vermicomposting method that I could expand from hobby size to large scale if needed/wanted.
The tool needed to be maintenance free or near so, inexpensive or free, take up little space, and effective at supporting and raising red worms.

This tool is complete and I have used approximately 15 boxes for raising worms over the past 12+ months. 

The description herein is the third iteration of this concept, the first two were similar but had problems. Version 1 had larger sides and when full of material, the box was difficult to lift. Version 1 also had a 1/2" hardware cloth mesh with openings that were a little bit too large. Version 2 used reclaimed cedar boards that were reduced to about the same size as the current version. Version 3 uses treated lumber that I bought as scrap for a token $25 and used 2x4s as the corner pieces rather than 2x2s.

Sourcing of Materials
While the metal hardware cloth may be hard to find used, it is very likely that people building this project can find the wood and potentially the screws online at sites like craigslist or from a Habitat for Humanity ReStore. All of the wood for my project came from material I bought as scrap ($25 on craigslist) from a homeowner who had built a fence and cut the boards off all at two different lengths that were perfect for this project. Here is a list of what I used, although comparable materials may be substituted for any item:

  • 100 feet of 24" galvanized metal hardware cloth 1/4" mesh   -  purchased on ebay for $71.65 in early 2018
  • Severe Weather (Common: 5/8-in x 5-1/2-in x 6-ft; Actual: 0.625-in x 5.5-in x 6-ft) Wood Southern Yellow Pine Dog Ear Wood Fence Picket  -  Lowes Item #635548
  • Power Pro #8 x 1-1/2-in Ceramic Deck Screws (75-Count)   -  Lowes Item #755687
  • Deck Plus #10 x 2-1/2-in Ceramic Deck Screws (5-lbs)    -  Lowes Item #894289
  • Fas-n-Tite 1-1/4-in 11-Gauge Electro-Galvanized Steel Roofing Nails (5-lbs)  -  Lowes Item #107798
  • Scrap 2x4 pieces, pressure treated or not

Step 1.

Determine the size you want the boxes.

I recommend using an opening that is the size of the hardware cloth. In my case, I used the 24" wide hardware cloth width as the inside width.
There are six boards for the box and four corners for added strength.The ends consist of four boards (2 on each end), with a front and back board of the same length.The six boards can be three different lengths, and I chose 25-1/2" front and back board lengths because I bought them cut at this length.

Step 2.
Cut boards to length using a saw.

A miter saw works well, as would a table saw, circular saw, or hand saw. Cut six 2x4 scrap pieces to 5-1/2" long (or the height of your boards if not 5-1/2".) Four of these will be the corner pieces and two will be for securing the hardware cloth in Step 10. The ends consist of two different board sizes, the outer board (25.25") being about 1.25" longer than the inner board (24"). The inner board will be centered on the outer board as you'll see in the next step.

Step 3.
Lay out and cut hardware cloth.

The hardware cloth should be cut about 8" longer than the length of the front board.  My boards are about 25 1/2" long, so my hardware cloth is about 33 1/2" long. Note that I say "about" a lot because we aren't building a piano. As you can tell from the pictures, measurements need to be 'close enough'. The worms won't care.

Step 4.
Place hardware cloth and secure one end

The hardware cloth is sandwiched in between the two side boards such that the screws that hold the sides together also hold the hardware cloth in place. So looking at a corner from the side view there will be two 2-1/2" screws, one about 3/4" from the bottom of the outside board and another about 3" above the first screw. Secure the side boards with the hardware cloth edge 4" above the bottom of the boards, in between the two boards to the corner 2x4. The best way to do this is to start the screws with a screw gun so that they are attached 5/8", just about ready to come through the outer board. Then place all the material together (outer board, hardware fabric, inner board, then 2x4) flush so that all pieces will be uniform at the bottom of the box. Make sure the hardware cloth is even and 4" above the bottom of the board. Then screw the 2-1/2" screws through all the material into the 2x4. Repeat for the other corner to complete the side.

Step 5.
Bend the hardware cloth to 90 degrees

With the hardware cloth secured by 4 screws, you can bend the metal to 90 degrees to make the bottom. It will be flapping in the breeze until Step 8.

Step 6.
Attach front and back boards

The front board will attach to the 2x4 installed in Step 4. Use two 1-1/2" screws to secure the board such that the top edge and bottom edge are the same height as the outer side board and the end of front board fits securely against the outside board. Ditto for the back.

Step 7.
Attach 2x4s to front and back boards

With 1-1/2" screws, attach the far end 2x4s so the outside edge allows for the inner board to fit flush with the front board. Again, the best way to do this is to start the screws with a screw gun so that they are attached 5/8" into the board. Then hold the 2x4 and inner end board in place and secure. Ditto for the back board.

Step 8.
Attach the last inner board

With the 2x4s secured to the front and back boards, we will now use 1-1/2" screws to secure the inner board AND THE HARDWARE CLOTH to the 2x4. Depending on how even the hardware cloth was secured in Step 4, you should be able to pull the metal under the bottom of the inner board and up the side roughly 4". Bend the metal as best you can at a 90 degree turn and as tight as you can to reduce sag in the metal mesh. With one or two 1-1/2" screws, CAREFULLY secure the hardware cloth to the inner board and the 2x4. The screw needs to be tight enough to hold the hardware cloth in place until the next step. Repeat for both sides.

Step 9.
Secure the last remaining (outer) board

With the inner board and hardware cloth secured in Step 8, the outer board should fit snugly on the end, covering the inner board and both the front and back boards. Secure the outer board with four 2-1/2" screws, two through each 2x4, such that the screw will also secure the hardware cloth sandwiched between the two end boards.

Step 10.
Secure hardware cloth to the front and back

At this point, the box is complete except the hardware cloth will droop in the middle of the box. To fix this, secure the two remaining 2x4s, laid sideways, to the bottom of the front and back boards. Center the 2x4 in the middle of the board and secure with two 1-1/2" screws. Flip the box over and nail two roofing nails to secure the hardware cloth to the 2x4. Can you use screws? Sure. But I've found from experience that after a while the hardware cloth will come off of the screw heads. That's why I use roofing nails now. They have more surface area and hold well. Another trick, when securing the roofing nails, it's best to place a piece of scrap lumber under the 2x4 and on a firm surface (like a work bench or driveway) so that as you hammer away, the 2x4 doesn't dislodge from the screws you just put in.  

Known issues:
Boxes, when full, can get heavy. I tend to stack material in the center and put a new box on top before completely filling the top box. Handles may be a good addition. I've not done it yet, but a 2x2 screwed in the sides should do it.

Other possible uses:
1) I am currently making a BSFL (Black Soldier Fly Larvae) box that is based on this implementation. I will post about it separately.
2) I used the same box, without the hardware fabric, as a potato bin. As the plants grew, I added another box (without the metal mesh) on top and filled the exiting box with light weight fill dirt. My goal this year is to grow 25 lb. per square foot. Last year, I only yielded about 5 lb./square foot, but only had 2 plants and both were planted late.


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