Also be aware that pallets from one manufacturer to another are not always uniform in size. For this system, it’s preferable that they’re all the same size. It makes for a better looking finished product and helps during assembly.
Pallet Selection. Pallets are made from all different types of wood. For a compost bin, it’s preferable to find those that are rot resistant, such as oak or cedar. Pine, although easy to find, does not stand up to the elements as long. For strength and durability, you can’t beat hardwood.
Most importantly, choose pallets that have not been chemically treated. The most common treatment methods for pests and pathogens are either heat-treating (marked on the pallet with “HT”) or fumigation, using Methyl Bromide (marked MB). Stick with heat-treated or new virgin wood if you can find it.
Assembly. Assembly is straightforward and intuitive. All you need are some all-weather deck screws (I used 3-inch length) and a drill with the appropriate bit. That’s it! Here are the steps to make the three-bin pallet composting bin I built in Episode 225 of Growing a Greener World.
1. Start with a level surface for the area where your system will set and assemble it in place. For the three-bin composting system I built, you will need seven pallets: one for each outer wall, two for the dividers to separate the bins, and three across the back.
2. I first attached the left outer sidewall pallet to another pallet that would serve as part of the backside with several of the screws.
3. Next, add one of the inner pallets that will serve as a divider of each section. Secure it against the same (first) back pallet with several screws.
4. Add the middle pallet that will make up part of the backside. The dividing pallet mentioned above is what secured the back pallets in place. With the remaining four pallets, work your way across for the next two sections in this same manner. In no time, you are finished with the basic setup and ready to compost.
The Options. The assembly was so fast and easy, I felt like I wanted to spiff mine up some more. Although totally unnecessary, I liked the idea of having a cover over the bin that would hold my finished compost. My improvised solution consisted of a cut-to-fit sheet of corrugated plastic screwed to a wooden frame made of 2×2 pine. I then attached two hinges to the fame and secured them to the outside of the back pallet.
Two larger hinges were also used to attach the outside pallet wall of the finished compost section to the back pallet. My thinking was it would be a nice way to swing open that side so I had better access for retrieving compost. In hindsight, it’s a nice feature but it’s not necessary and more trouble than it’s worth.
Consider grabbing an extra pallet to use just for additional parts. I removed the slats from it to place in between other slats of my finished bins wherever I wanted to close some of the gaps. It’s a smart and simple fix to help keep more of your precious compost in place.
A final step that I strongly suggest is to screw a long treated 2×4 across the backside of the pallet wall. The extra stability it provides is a simple and inexpensive option to reinforce the entire system.
You can watch the composting episode and see just how I built this bin here.
If you’re looking for another great use of pallets, check out our most popular post on the Step by Step Instructions for Building a Pallet Garden, including the how-to video here.