Building an affordable composter is essential for any gardener, but adequately planning for it is just as important. You see a lot of information on the internet about the various compost bin types you can build. These composters vary in terms of materials, size, cost and ease of use. Very few people choose their composter based on the amount of compostable material they have or how they plan to use the composter. Spending a little time up front to determine the necessary volume and functionality of your composter will save you a lot of back-breaking work and frustration in the future. Once you have the right composter in mind, you can start building.
I like a compost bin with some room, so this one is 108 cubic feet. Most of the year I don’t have nearly enough organic material to fill the bin, but during the spring when I collect grass clippings or in the fall when I rake leaves, it can be overflowing. It’s a super simple design and can easily be modified to the specific size constraints you’re looking for.
Best of all, the materials for this compost bin are inexpensive to free. Look for really cheap rejected lumber at your local lumber yard and trim to size. Many lumber yards have a reject piles for lumber with gnarled edges or split ends that carpenters won’t use for projects. Picking these boards up at a discount is usually easy to do if you ask the warehouse manager.
- 4 3-foot 2x6s
- 8 6-foot 2x4s
- corrugated-plastic soda or beer signs
- 48 3-inch screws
- staples for corrugated plastic
Build two 6-by-3-foot rectangles that will function as the two long sides of the composter, with the 2x4s serving as the top and bottom boards of each side and the 2x6s serving as the side supports. The use of 2×6 boards offers extra reinforcement to the corners, and their 3-foot height adds enough room in the bin to get good heat generation. Heat is created by the microbial breakdown of organic matter within the bin, helping to burn off weeds and pathogens, as well as self-insulate the pile. Even if you don’t feel that you could fill a large bin, like the 6-by-6-foot-area one we’re going to build here, build your composter tall enough to allow you to create a pile 3 feet deep.
For each rectangle, lay two 2x4s parallel to each other, 3 feet apart, on your work table. Place a 2×6 on top of each end of the 2x4s, so it’s even with the top edge of the top 2×4 and the bottom edge of the bottom 2×4. Fasten the boards together with 3-inch screws—three screws in each corner should do the trick.
To complete the composter frame, attach two 2x4s to each end of the rectangles you built. I learned the hard way that it’s best to have the side of the rectangle with the 2×6 protruding off of it placed on the inside of the composter. This will give you a nice ledge all the way around the composter to move and carry it.
Ask a second person to help you attach the 2x4s to the sides, as it will require you to balance the pre-made rectangles vertically. I would recommend using just one screw initially to attach each of the remaining 2x4s because as you attach a board to one side, the other side will begin to twist and lean. You can work to make the sides plumb before adding the remaining screws for stability.
You will need some sort of material to hold the organic matter in the compost bin. Many composter designs recommend using pallet wood, but I don’t care for this, as it makes the composter heavy and because a lot of pallet wood is treated with chemicals I don’t want around my food. Other composter designs recommend using wire mesh or chicken wire. These are both good choices, but they have a couple drawbacks: They are both pricey, and a fair amount of your organic matter will get caught in the wire when you try to turn your compost. I like to use corrugated plastic for the sides. I can usually get it for free from a local corrugated supplier, or I can get soda and beer signs from local grocers.
Most composter designs you’ll find are built without a plan for turning your compost. Compost is wet, heavy organic matter that doesn’t turn easy. Trying to turn a large pile using a pitch fork will create a sore back and keep you from regularly doing this chore, slows the organic matter breakdown and making for less effective compost in the long run. With the corrugated plastic on the inside of this composter, two people can easily pick up the composter and move it to the side while you turn the compost with a front-tine-tiller or the bucket on your tractor. Once you have the compost tuned you can simply place the composter back around the pile and let it heat up again.