Worm Compost Bin

Submitted by niecey on Wed, 03/30/2011 - 13:49
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worm compost bin

About Project

A worm composter can be kept indoors or out. Fill the bin with bedding, such as shredded newspaper or shredded dried leaves. Place some sand/dirt on top, put your scraps in a layer in the middle then cover with more bedding/dirt. When you add new scraps, dig in a little then cover them up again.

This design has two stacking units, but you can add as many as you want, depending on how much waste your family produces. The units fit into each other and lift up easily to rearrange or carry to the garden etc.

Fill the bottom tier with bedding, dirt, scraps and worms. As it fills up, start adding the material to the next tier. The worms should eventually move on up to the top when they run out of food in their level, leaving beautiful castings behind - perfect compost for your garden. When you empty the bottom unit into your garden, place it on top and start over, filling it as the bottom unit becomes saturated.

This is my first project from my own plans. I built it before improving the plans so my my actual worm compost bin that I built is full of flaws, but I've worked on it in sketchup and I think it's good to go now. You'll do a better job than I did.

Also, I used pine, to keep costs down and I finished it with a clear, food safe protective coat. Don't use paints or stains which could leech toxins into your compost. If you can fork out for cedar it will last much longer (and will look better too).

Don't judge the project by my photos of the completed one. I made lots and lots of mistakes. I think the final plans should be good though (maybe I'll make another one..). This is a fun way to compost. The kids will love it. Worms make wonderful compost that will enrich your garden. And they're lovely little pets too.

Keep it sheltered if possible, insulate in below freezing temperatures or move it indoors. It should be odorless, if you notice an odor, you probably just need to give it a stir to let some air in on the action.

worm compost dimensions
It stands 20 1/2 inches tall and is 14.5" wide and 14.5" long


Shopping List

(plywood) 2'x4'
(1x2) 4
(1x3) 2
(1x6) 2
2 pieces of mesh, about 9" by 9" each
food safe protective coat (optional)

Cut List

(Plywood) - 2 @ 14.5" X 14.5"  (or you can use boards stuck together with pocket hole screws and glue, especially if you want to use cedar for weather resistance)

  4 @8"
  6 @ 11.5"
  6 @ 11"
  2 @ 9.5"
  2 @ 10"
  4 @ 4 1/4"
  6 @ 14 1/2"

  4 @ 4 1/4"
  4 @ 14.5"
  4 @ 9.5"

  4 @ 14.5"
  4 @ 13"

Cutting Instructions

These dimensions are based on 1x2 boards being 1.5" in actual measurement and 1x3 boards being 2.5". If your boards are different size you will need to adjust some measurements.

Tape Measure
Speed Square
Safety Glasses
Hearing Protection
Kreg Jig
Circular Saw
Staple Gun
General Instructions

Please read through the entire plan and all comments before beginning this project. It is also advisable to review the Getting Started Section. Take all necessary precautions to build safely and smartly. Work on a clean level surface, free of imperfections or debris. Always use straight boards. Check for square after each step. Always predrill holes before attaching with screws. Use glue with finish nails for a stronger hold. Wipe excess glue off bare wood for stained projects, as dried glue will not take stain. Be safe, have fun, and ask for help if you need it. Good luck!


Step 1

Start making the main units. Use pocket hole screws and jig to make a box 14.5" by 14.5". Use wood glue. Make 2 of these.

Step 2

Next start making the bottom of your units. Fix your 9.5" and 14.5" (1x3) boards to one end of your units. You can make a square face with the (1x3) boards first using pocket holes and then screw or nail the face onto the unit, or you can just screw then pieces on one at a time.

Step 3

Next take your (1x2) pieces cut at 11" and 8" and set them 1 3/4" in from the edge. Again you can attach them to each other first with pocket hole screws to make it tighter if you wish.

Step 4

Staple your mesh using a staple gun or hammer and staples. Place the staples at about the midpoint on the (1x2) boards and fold up or trim off any excess mesh hanging off the edges.

Step 5

Step 6

To make the bottom/legs piece, take one 14.5" plywood piece (or boards screwed together farmhouse style) and fix the 4 1/4" (1x3) pieces on flush, using glue and pocket hole screws.

Step 7

Add the (1x2) leg pieces at right angle to the legs you attached in step 6. Screw them with pocket hole screws into the other leg and into the plywood base.

Step 8

Use pocket hole screws and glue to attach the (1x2) trim to the base plywood and to the legs.

Step 9

Fix (1x2) boards around the rim just as you did with your main units. This allows your units to stack into the bottom/leg piece. Your leg piece is complete.

Step 10

Now make your lid. Take your 14.5" plywood (or boards screwed together) and screw 2 (1x2) pieces 1 3/4" in from the sides. This will allow your lid to fit into the hole on the top tier.

Step 11

Stack your pieces on top of each other. Do not glue or screw or nail the pieces together. You want them to be able to be removed frequently and easily. They should sit in each other nicely. If it's too tight you can file or sand down as needed.

Finishing Instructions
Preparation Instructions
Fill all holes with wood filler and let dry. Apply additional coats of wood filler as needed. When wood filler is completely dry, sand the project in the direction of the wood grain with 120 grit sandpaper. Vacuum sanded project to remove sanding residue. Remove all sanding residue on work surfaces as well. Wipe project clean with damp cloth. 

It is always recommended to apply a test coat on a hidden area or scrap piece to ensure color evenness and adhesion.
Finish Used
If you wish to use a protective coat/stain, make sure it is safe for food contact. Look for the kind used for wooden spoons/butchers blocks etc.