An Urban Pallet Compost Bin Design
Welcome to the 2nd article in our composting series! If you missed it, last time I discussed how we got started composting and the compost tumbler basics that we have been practicing for years. If you are gardening in a small space, urban area, or are just nervous about learning to compost, I highly encourage you to check out compost tumblers. We love ♥ ours.
To continue our composting story, this year’s garden goal is to expand, refine, and improve our composting system. Currently we do not make enough compost to amend our entire yard, but we have come to the point where we feel we have some options to expand our compost area. PS: we have been supplementing our homemade compost with compost bags from the nursery. There’s nothing wrong with buying compost!
Choosing our compost bin materials
While researching what I wanted to use to build our compost bin, there were a few considerations I had in mind: budget, aesthetic, and protection. Wood pallets are a very common DIY material but the main reason we chose them is because my husband was able to find some really nice pallets at work—-so free!!!!
NOTE: Wood pallets are not regulated like the wood you buy at the hardware store, so it is very important to look for the “IPPC” stamp on any wood pallet you are going to use. The IPPC is a regulatory agency that over sees the production of pallets. You may find some without a stamp but we recommend only trusting pallets that have the stamp. The IPPC lets us know how the pallet was processed—debarked (DB), heat treated(HT) or other processing. The main thing we want to avoid is treatment with “Methyl Bromide” as designated by an “MB”. Methyl Bromide is a pesticide used to protect the pallets from insect damage.
Critter Proof Your Bin
Wood pallets have large slats that critters (like rats, mice, and squirrels) could definitely fit through. We lined the inside of our bin with this 1/4″ hardware cloth. This material is already recommended by master gardeners for lining the bottom of raised beds to protect for gophers, so it made sense to use it as a lining for our compost bins. Hardware cloth also allows for airflow/oxygen around our bin, which is a necessary part of the composting process.
In addition to lining the inside of our bins with hardware cloth, I also wanted a removable front cover and a lid to prevent critters from getting inside. Since all sides of our bin have slats and mesh, the front and lid could be solid.
Advantages of a Bin Compost System
If you look around the internet for compost bin systems, you will typically stumble across a traditional arrangement of 3 bins. The idea is that one bin can be for newly added items that can be turned into the second bin to start decomposing more while a third bin is for finished (or almost finished) compost that can rest until it is time to use it. This is a great system, and ideally one I would like to have in my yard, but we just don’t have the space. Therefore, I decided to just work with two bins—this will at least allow us to have two batches of compost going at one time.
Ultimately, the biggest advantage of building bins for composting (over using a tumbler) would be having enough organic mass to start hot composting.
Hot composting is a method of composting where you harness the heat generated by the microbial activity of your compost pile to increase the decomposition rate and kill pathogens and seeds. Hot composting allows you to produce larger amounts of compost in a shorter amount of time (sometimes as little as a few months).
Since we have been using a tumbler this whole time, this will be my first time hot composting. I’m really hoping this “casual composting” gal is ready to be more hands-on and active with composting. The idea of being able to produce larger amounts of compost in less time is truly what made me decide on compost bins for this extension of our urban composting system.
Urban Composting: Our 2 Bin System with a Twist
What do you think of my name choice? I was trying to think of a way to describe our new compost system design, and I think it’s a 2 bin system with a twist!
So, you already know why we are going with only 2 bins, but what’s the twist? After filling our compost bin, I noticed that there were some fruit flies within two days and a fresh food scrap smell. I had already followed recommendations to 1) bury all food scraps 2) follow a 1:1 brown to green ratio. This really bothered me because being a considerate nieghbor is very important to me.
Thinking on these concerns, I decided that I would use our tumbler as a “pre-processing” first bin. I have been adding my fresh food scraps (along with an equal amount of browns) to our tumbler until the food has broken down enough to be transferred into one of our pallet bins. Anything like pruned garden leaves, grass clippings, coffee grounds, discarded plants, and less “yummy” kitchen scraps will go straight into the pallet bins because they don’t attract flies or critters. For example, cabbage leaves and kale don’t attract fruit flies, but fruit scraps and butternut definitely do! So far this has been working beautifully!
Now that you have read a little background on the design choices for our compost bins, here is a list of materials and a general breakdown of how we constructed our pallet compost bins.
Wood Pallets (with the IPPC mark and no MB mark) 2 per bin.
Hardware cloth * We used 1/4″ mesh
corrugated plastic for the top
scrap wood 1″X1″ for top frame
1/2″ plywood or OSB for the front panels
2-1/2″ screws for screwing the pallets together
3/4″ screws to attach the plastic cover and to mount the front brackets
1 set of hinges for the top
4 of these brackets to hold the front panels
A drill or impact driver for the screws if you don’t have one *This is a great kit by Milwaukee
A saw for cuts.* We used a circular saw for the front and top, but a cheap miter box and saw would be perfect.
Gather Materials and Prep Location
We chose to put our bins on our side yard. The ground there is decomposed granite (DG) that is mostly rock hard. If you are placing your bins on soil, I have heard from other gardeners that critters can possibly dig under to get to your scraps, but a lot of compost bins do just fine resting on dirt. If critters are a major concern, you could always place hardware cloth on the bottom as well, or put down a piece of plywood.
Make sure your location has been cleared and is level.
The most common pallet size is 40″ x 48″ but just make sure you choose pallets that will fit in your designated space. You will need 2 pallets that are the same size. We used 1 full sized pallet for the back and then cut another in half to make the sides.
Cut One Pallet in Half
Take one of your pallets and cut it in half using a saw. Be sure to cut the 48″ side in half—this leaves you with 2 40″ x 24″ pieces. These will be the sides of your compost bin.
Construction of the Frame
Now lets start building! This process is a lot easier with a helper, so you don’t have to hold a pallet while you try to screw another pallet to it. Pick a nice flat spot to start building, where you can get all the way around the bin as you work.
The side of the pallet that is normally the top (the side with the most slats) will be the inside of the bin. Stand your back pallet on edge so it is 48″ wide and 40″ tall. Have a friend hold this while you stand one of your side pallets up so it is 24″ long and 40″ tall. Push the pallets together so the outside edges match up and have your helper hold both pallets upright so they don’t fall over. See photo below.
Next, we screw these two pallets together using the 2 1/2″ screws. Depending on the pallet style you might have to angle the screws as you put them in. We screw the pallets together through their main supports for best hold.
Repeat that process on the other side with the third pallet piece. That is your main pallet frame from the compost bin!
Watch our video under the “lining with hardware cloth” section below to get more instructions and a great visual on the bin.
Lining The Bin with Hardware Cloth
We lined the inside of our bin with hardware cloth to keep critters out and compost in. Watch the video tutorial below for a visual on how we lined our compost bin. Hardware cloth also lets the pile “breathe” with airflow and oxygen which is essential for proper breakdown.
Lining the bin is very simple, and we do it with just one cut in the hardware cloth. Start on a side pallet and fold about 1” around the front and staple in place (see video). If the staples don’t go all the way in you can just tap them with a hammer. Just make sure your wire edge lays down flat so it isn’t sticking out dangerously.
Next, roll the cloth around the inside of the bin. Staple as you go and press the cloth tightly into the corners.
When you have rolled the hardware cloth all the way to the other side pallet, don’t fold it over the front edge yet! Now we will make our cut.
Put on a pair of work gloves (it can get a little sharp) and use your tin snips to start cutting. Leave about 1” extra hanging off the front of the bin so we can fold it over like the other side.
Lastly, fold the cut edge over the front edge and staple it down. *You can use your hammer to help the wire lay down more easily as that fold can be a little tricky
Creating the Front Panels
We create our front panels with scrap 1/2″ plywood we already had on hand. You could also use something called OSB (oriented strand board). It is cheaper than plywood, but not quite as sturdy.
To figure out the plywood size for the front, you use your back pallet as a measurement guide. Our total size of our front cover is the same size as that back pallet, but we end up cutting it into two panels. In our example, we use a 40″ by 48″ pallet as our back pallet. So, the front cover will be 40″ by 48″ as a whole cover and then we will cut it in half so we have two 48″ by 20″ pieces. This is nice because most home centers carry 48″ by 48″ plywood and you can have them cut it for you.
Measure and cut your two front panels.
The reason we have two front panels is to allow for us to remove the top panel if needed while the bottom panel will prevent the entire compost contents from spilling out.
Making Removable Front Panels
We wanted the front panels to be removable for ease of turning our pile. We found these brackets at the home center and they were perfect for this purpose! Measure up the front side at 10″ and 30″ inches and make marks on the left and right side of bin. This is where you will be placing the brackets. It doesn’t have to be perfectly precise either.
Start with the bottom front panel. Have your helper hold the bottom half of your front cover on the bin (like it will be when finished) and hold your bracket in place. You must do this with the front panel on because you need to place the bracket properly so the panel can still slide up and out. Mark the holes of the bracket on the bin using a pencil/marker. DO NOT mark the holes on the front cover, just on the actual pallet side. Do this for both the left and right sides.
Screw the brackets to the bin using the 3/4″ screws and slip the cover in. Check for proper fit. You have finished the first front panel!
Assemble the second front panel. Have your helper hold the second cover in place, resting it on top of the bottom panel, and repeat the process.
Making a Top for the Compost Bin
So, this was the most complex part of the build, but still isn’t too bad. The cover is very lightweight, so using any 1″ wood scrap material for the frame of the top is fine.
We are going to build a wood frame. Start by measuring the top opening of the bin. For example, the opening on what we have built is 36” wide by 24” deep. We will need 5 pieces of wood for the frame—4 pieces to make a wood box frame and 1 piece for the center of the frame to make it sturdier.
Two of the pieces will be 38″— that is the width of our opening, plus 2″, so it will rest on the side pallets and not fall into the opening. 36” opening + 2″ would be 38” in total.
Three of the pieces will be 24″ long.
Using the 1-1/2″ screws and your friend (remember to say thanks for all the help) we will attach the 5 wood pieces together to make a frame for our top/cover. See the diagram below for how we assembled the frame.
Next, we need to attach our corrugated plastic roofing to our frame. Lay your wood frame on a flat spot on the ground, and then lay the plastic on top. Measure and mark the plastic dimensions you will need to cover your frame, and use your tin snips or some sturdy scissors to make the cuts. Your plastic should cover the frame completely. In our example the plastic is the perfect size to cover the top so you only need one piece cut to 38″ long.
Using the 3/4″ screws, attach the plastic to the frame. Optional : you can use these plastic supports to attach the plastic to lid it helps fill the gaps and give it a cleaner look. That is what we did and you can see how they work in the picture below.
Time to Add Hinges and Attach the Cover
Now that we have a top that fits our bin, it is time for hinges. Place the top on the bin and position it how you would like. Lift the cover as if it had invisible hinges already attached and have your friend hold it in place. Take your hinges, set them in place, and mark the screw holes with a pen/marker. Be sure to mark the holes on both the lid AND bin.
Use the hinge screws to attach the hinges. I like to attach the hinges to the lid first and then attach the lid to the bin.
That’s how we made our very first compost bin for hot composting! Thus far, I’m happy to report that we are LOVING it and obsessed with composting. If you follow me on Instagram, you’ve probably seen me post about how well our full bin has been performing. We are currently trying to keep our hot compost between 135-160 degrees F in order to expedite the activity, decomposition, and breakdown of the pile. The goal: have finished compost in 3 months or less!
Want to know how we fill our compost bin? Read How to Compost: Filling & Maintaining a Compost Bin
Remember, there are many ways to compost, but I hope that reading about our thoughts and plans will help you make decisions for your space as well. You can find many of the items that we used in our compost system on our Garden Supplies & DIY Amazon List.
See my previous post→ Urban Garden Composting: Our Compost Tumbler Basics
⇓ Have questions? Ask them below! Are you planning to start composting?⇓
PS: Tag me in your garden photos with #FreckledCA on Instagram!