How to Build a Compost Bin
Building a compost bin is something I’ve had on my list of things to do to ever since we moved here to the mountains. Compost is a great soil amendment for vegetable and flower gardens. Mature compost is the result of the natural breakdown of organic waste. Composting is the ultimate in recycling and considering organic waste makes up for more than 24% of municipal waste, composting is a great way to help the environment and save money.
Two weeks ago, I visited our local Lowes and picked up the wood and hardware needed to start building a compost bin. I love building things, especially when my kids help as I get to teach them. Building a compost bin turned out to not only be a useful project, but a fun a fun family project as well.
Compost bin design
I started out initially with a compost pile over near the woods behind our vegetable garden. Using a compost pile is a frugal way to get started, but not the most efficient way to generate or maintain good compost. Let me briefly overview some of the more popular ways to compost. I’ll touch on the advantages and disadvantages of each:
- Compost pile – Obviously the most frugal choice. Find an out of the way location and start piling. Advantages: inexpensive Disadvantages: eye sore, doesn’t produce mature compost quickly, can attract animals.
- Wire bin – Another frugal choice. Just take some chicken wire (or similar fencing), make a cylinder out of it and begin mixing your compost inside. Advantages: inexpensive, better than a compost pile Disadvantages: Difficult to “turn”, doesn’t produce compost quickly
- Compost Barrel – A compost barrel produces compost quickly and makes turning your compost a snap. Two of the many different barrel products are the Spinning Horizontal Composter and the Tumbleweed Composter. Advantages: fast compost, easy turning, attractive option Disadvantages: Somewhat expensive, makes a small amount of compost, will rust over time.
- Wooden Bin – A wooden bin produces compost quickly and can be built to contain multiple bins to facilitate making more compost. There are tons of plans on the internet. Advantages: Attractive, can be built specifically for your needs, adjusted to your budget, fun – if you enjoy wood working. Disadvantages: Heavy, can be pricey, not the best solution for the non-do it yourselfer.
Building a compost bin
After researching several plans, I decided to go with a plan I found on Lowes.com. It had a material list, was the size I needed, and was a multiple bin plan. I also really liked the way it looked and the plan included lockable covers, which was important for me in order to keep the critters (and our dogs) out.
If you can do basic wood construction, you can assemble this bin. The most difficult part is making it square. If you decide to go this route, invest in a good carpenter square. I promise, you’ll be glad you did.
I took the materials list to our local Lowes and purchased all of the wood and hardware. Make sure you get everything you need on the first trip. Nothing worse than having to stop your project in the middle and head to the hardware store. Total cost for me was $350.00, but you could save some money by using scrap wood or existing hardware you may already have. Don’t use non-treated wood though, or your bin won’t last long.
Assembly took about 10 hours. Although if I had been doing it by myself (i.e. no kiddos), I think it would have been more like 6-8 hours. The plans from Lowe’s are good, but not perfect.
Here’s the end result:
One of the best features of this plan is that the wooden slats you see in the front are removable. If you look closely, you’ll see that they actually slide into tracks and stack on top of each other. There is a 1/4″ gap between the boards to allow for air-flow to the compost. The gaps were obtained by placing two screws in the bottom of each slat and leaving them out 1/4″. The removable slats make loading, unloading, and turning your compost so much easier.
The plan also has a raised floor which helps keep your compost dry and allows airflow into the bottom of the compost bin. The lids also ease access to your compost, but protect it from being invaded by critters. In area that could be anything from our dogs to bears, but most likely racoons.
Overall I think it turned out very nice. It’s not perfect, but hey it’s a compost bin, not a piece of furniture right? One of the problems is that the plans from Lowes aren’t perfect. Let me share a few tips I learned along the way:
- If you aren’t real experienced at building wood projects, pick up an extra piece of wood for each size. The plans specify the exact amount of wood you will need. One bad cut, and you won’t have enough wood. As my grandfather and father used to always reinforce to me: “Measure twice, cut once“. You can always use the extra wood for other projects you’ll have.
- Use the step by step plans and not the downloadable diagram for measurements. They don’t match and the diagram is wrong. Use the diagram just as a visual reference.
- The materials tells you to buy two boxes of most nails and screws. Buy one. I have unopened extra boxes. I’m ok with that, as I always need them, but if you don’t do much wood work, it’s a waste of money.
- As you build the compost bin, constantly check to make sure it’s horizontally and vertically square. If you don’t, it will make putting in the slats and top far more difficult.
- Once you get the frame built, place it where you are going to keep it permanently. The completed compost bin is heavy. We made the mistake of assembling it in our driveway. Fortunately I have 5 boys and a truck, so we were able to load it up and hauled it up to our garden. But it was HEAVY. I’m guessing at completion (with no compost) it weights around 300lbs due to the treated wood.
- One area of the plan that was NOT clear is how long to cut the the 2x2s for the lid. Measure from the back to the front of the slats. The plan seems to imply that you measure from the back to back of the slats. If you did this (like I did), the locks for your lid won’t work. I had to cut two small pieces of 2×2 to place the locks on so they would work. Look at the locks on the right side in the picture and you’ll see what I mean.
- While you can do this project with a handsaw, there is enough cutting that a power circular saw would be highly recommended. If you don’t have one, pay the extra for a Dewalt. A Dewalt saw is not the most frugal option, but it cuts wood like a hot knife through butter and will last you forever. I believe that paying more for quality tools is worth it in the long run. I’ve had mine for over 5 years and it’s never skipped a beat.
Filling it up with compost materials
Once we had it placed, we moved the compost pile into the bin. This gave me a chance to interweave some fresh material and also aerate the pile. I thought our pile would fill up at least 1 bin and most likely 1/2 of the other. Turns out in only filed about 3/4 of the one bin.
The secret to successful composting is the proper layering and ratio of materials. You want 1/3 green and 2/3 brown. Green includes things like: grass clippings, vegetable peelings, manure, seaweed, plants and plant cuttings. Seaweed? Yes, I compost the extra algae growth from my saltwater aquarium. Brown materials include: leaves, hay, coffee grounds, shredded paper, wood ash, sawdust, and teas bags. Layering your bit with green and brown materials in the right mixture is critical to having a productive compost pile. Don’t use full sheets of paper or newspaper, as they will just compact your compost pile. Also, shred leaves before placing them in the bin to avoid the same problem. An easy way to do this is to run over the leaves with a lawn mower a few times.
You can see here in this picture the initial layering when we loaded the new bin:
I’ve since added more grass clippings to the top. All the white is shredded paper out of my paper shredder. I’ve also started the second bin as well with a base of dry leaves I found under our deck. Leaves make for great compost.
To hold kitchen scraps until we can take them up to the bin, we keep a 5-gallon bucket with a lid next to the trash and other recylables. You can pick up the bucket and lid at Lowe’s for next to nothing in the painting area. Here’s a picture:
Now we wait. Mature compost generally takes 3-6 months depending on the materials. The only care and maintenance required is to turn the materials every few weeks to keep things aerated. Airflow is a critical component to good compost.
A tell tale sign that your compost is maturing and breaking down properly is the temperature at the center. It should be between 110 and 160 degrees F. Yes, that hot. It surprised me too. I have a long stem thermometer and tested my temperature last week: 120 degrees F. So I’m composting away! (yeah I know, I’m excited about compost…my wife picks on me too).
We’re adding new compost materials to the second bin now, while the first bin “cooks”. I plan to build a compost sifter soon too using some scrap wood and left hard hardware fencing I have. This will allow us to filter out all of the materials that didn’t fully breakdown and have good clean compost.
To make sure I turn it on time, I’ve added repeating entries to my Google calendar to remind me. Most experts recommend turning it every 4 weeks, so that’s what I’m doing. I’ll keep you posted!
Here are some really good resources I found on composting you should check out:
- Blue Ridge Gardener – Compost Resources
- Vermicomposting – This is on my list too.
- EPA site on Composting
- Composting 101
- Cornell University Composting
- Compost Confidential
Do you compost? Have any tips you can share? What type of compost bin do you use? Add a comment!