2′ x 4′ Continuous Flow through Worm Bin

Posted by By at 23 March, at 22 : 53 PM Print

2′ x 4′ Continuous Flow through Worm Bin

2x4 worm bin

This worm bin is a quick and inexpensive project that can easily be completed in a day. It’s a continuous flow though design which means you feed the worms from above and harvest the worm castings from below. It’s 2′ x 4′, stands 4′ tall and can accommodate 8-16 lbs of worms. Bellow you will find a list of the materials and tools required, plans in a PDF format, a cut list and photos. Feel free to contact me if you need any clarification, and I will do my best to help.



10 ft 1/2″ electrical conduit Qty 5

2x4x96 Qty 7

4×8 sheets of 1/2″ exterior grade plywood Qty 2

3″ decking screws

1 5/8″ decking screws

Hinges Qty 2 sets




Circular saw


Straight edge


Jig Saw (optional)

Miter saw (optional)

2×4 Continous Flow Through Worm Bin

Cut list:

Three 2x4s are cut into 47″ pieces Qty 6

Two 2x4s are cut into 18 1/2″ pieces Qty 8

Two 2x4s are cut into 20″ pieces Qty 6

The five pieces of electrical conduit are cut into 23″ pieces Qty 25

Four 6″ pieces are cut from remaining scrap

2x4 worm bin - panels

The cuts from each plywood sheet are shown in the photo above. The same drawing is also part of the PDF plans.



2x4 worm bin - frame

You will need to drill 25  holes 3/4″ in diameter along the length of two of the 47″ pieces before you start the assembly process. Once the holes are drilled, you can begin assembling the worm bin by screwing 3 frames together. Each frame uses two 20″ pieces and two 47″ pieces. You will slide the 23″ sections of electrical conduit into the holes of the middle frame.

You continue the assembly process by screwing the bottom piece (23″x47″) to the bottom frame. Once it’s attached flip the frame over and attach the 6″ legs to the frame. After the legs are attached you can flip the bottom frame back and attach the sides and back to the bottom frame.

With the back and sides attached, start building up by screwing a 18 1/2″ 2×4 in each corner. Once those corner pieces are attached, you can place the middle frame with the electrical conduit into position using the corner supports to hold it in place as you attach the frame with screws.

Repeat the process with the top frame and you should have something that looks like this:


Next attach the upper front panel with screws around all edges. The bottom front panel will be attached with hinges so you can access the bottom to harvest the worm castings. The top is also attached with hinges so you can feed your worms.


That’s it! You’re basically done. I would advise you drill some 3/4″ holes at the top of  each side to provide some ventilation.

After a little paint, you should be left with a continuous flow though worm bin that looks like this:


I hope you found this information useful. If you have any questions feel free to contact me and I will help in any way possible.










  1. Hi Gray,

    This is the best design I have seen and I just built it with my daughter . We’ve got the worms and am getting ready to get it going but I’m worried that the holes in the bottom are going to let the worms and uneaten debris fall into the lower cupboard. Any suggestions ?

    Kab, 2 years ago Reply

    • I’m glad you liked the design and got to build it with your daughter. To keep the worms and bedding from falling through initially, you cover the conduit with newspaper first and then add the bedding and worms. As the paper breaks down and decomposes that will allow the castings to fall through. You will have some worms that fall with the castings as well, but if you keep the bedding deep enough only a few worms will fall down. I check the castings in the bottom occasionally and return and worms that have fallen to the top. I recently put a video on YouTube about how I manage the system. https://youtu.be/lSp_aJlN-Jo

      Gray, 2 years ago Reply

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