Compost bin plans
Materials I used to build the compost bins:
Step 1: Build the posts for the compost bins
I have a bunch of plans for this larger size that I made myself but I also have a bunch of smaller plans. Since I live on land and have a huge garden, I wanted extra capacity. I put this right outside my garden, next to a potting shed I built a few years ago. I’m going to skip drilling the holes as this is standard practice but know that there are 8 holes required for this build and a 4×4 can fit in each one. The back posts are simply cut to size, then snapped into place.
The front canals have a central canal that extends most of the way to the bottom. These are what make the front slats adjustable. To cut these, I go to the table saw. The trick to cutting the canal easily is to put up two fences. I make the first pass with a table saw fence set up to mark the rightmost edge of the channel.
On my second pass, I use a scrap straight board that is aligned to the left of the desired channel. Another clip is placed on the feeding table to determine the depth of the channel. When it’s time to run the third pass, I don’t use either fence, but instead float my 4×4 between the two to clear as much of the center as possible.
Don’t worry if you don’t get everything, the chisel can do the rest of the cleanup. Typically when working with a chisel, you want to use the large flat part to move along the wood. However, in such situations where the handle prevents you from going flat, know that you can flip it over and use that small bevel instead. It’s a smaller surface area, so it’s harder to keep flat, but just place a finger or two on it to help.
Step 2: Prepare the posts to be placed in the ground
Okay, with the channels established, let’s put these posts in place on the front line. With the posts in the ground, make sure you are using pressure-treated lumber. In fact, I recommend Prowood which also has markings to help you pick out the correct treated material for your specific project. For my posts, I made sure to find the label that said “Ground Connection”.
One of my favorite things about Prowood is that they use the latest advances in pressure treated wood to color their wood! So instead of the standard green, you can now choose from a variety of colors and skip the dyeing step. The wood is so rich in color that the dye is pushed deep into the wood fibers ensuring it will withstand the elements for years.
Step 3: Put the posts in the ground
Let’s move on to putting these posts in the ground. I didn’t feel like messing with concrete, so I used decomposed granite as a substitute for this project. These can be found packed in the garden section. On each post, I fill the hole about 1/3 of the way, then tamp it down, also known as compacting it.
To start, I like to use a short snip and I chose the 1x so I can fit it into tight spaces around the posts. I’ll apply enough pressure to keep the post from tilting a ton so that I have both hands to set a level on one side of the post and push it into a plumb position. Once I get it there, I press more, then repeat on the other side of the same post. After getting it right, I fill the hole more and then do my best to compact it tightly.
I have a rock bar, because everyone in the hill country has that, and it actually comes with a 2-inch round gasket on one end, so that’s what I use.
I recommend that you start with the end, then jump down the line to set the other end column, and then delete in between. More than making sure each post is secure on two sides, you also want to make sure the faces are square to each other, and I’m using this length of 1 x 4 to test that.
Step 4: Level the posts
Next, I leveled all the compost bin posts flush with each other. To do this, I found the height of the shortest post, then cut the top of the other posts to match. I did this in two passes using a circular saw. This is much easier than trying to get all eight holes exactly the same depth.
As I was cutting, I cut a shoulder into all four back posts. Be vigilant because if you navigate a post as much as I did here, you will definitely have to rework it. A good tip is to not worry too much about it being completely secure yet, just lock it down, because the next step is to add 2×4’s that go across all 4 of these back posts to secure them together.
At this point, I made sure the columns were completely stable, so I could ram and compact them as much as possible.
Step 5: Add the screening to the compost bin
Go ahead and take your time setting up these posts because if they are firm and square, they will make everything else from here fly. The next step is to line the back of the compost bin. There are a few options you can follow for screening but I recommend a hard cloth. I’m using a crown stapler to hold it in place, trying to work out the bubbles as I go. I pin it in a few places just to get hold of it, and then when I don’t have to hold it for much longer, I go back and pin it completely. I imagine there will be a fair amount of compaction once these compost bins are full.
For cutting solid fabric, you can certainly use a pair of side cutters, but a much faster method is to use a right angle grinder with a cut-off wheel. Don’t worry if you get into the woods a little.
Step 6: Cut the fence for the compost bin
At this point I go back to my shop and cut some bars that run from the rear pillars to the front pillars. I use my bandsaw to cut two different shapes on one end of these pieces. The T will be placed in the middle, while the L will be placed on the outside. For all of these, I start by attaching the back of the rail to the back post. When I move to attach the front, I move the rail in or out with my knee. Things should be stable at this point, but each one was a little off. No problem though, after installing it in the front I was once again able to put down the granite.
Step 7: Hardware cloth for compost stalls
With these bars in place, you can see the shape of each booth emerge. To complete it, I secure it with cloth on all interior faces. They are cut roughly to size first to make them a little easier to handle, but once I start pinning them, I leave them running long from the front because it’s easier to cut them perfectly after. In fact, if you have a friend around, have him or her grab square-nose pliers and pull the cloth tight while you secure it. This is very useful in the front extension of the house.
Note: This air gap between each stall is intentional. Air flow is a big contributor to creating a healthy compost pile that doesn’t give off an unpleasant odor. If you compost properly, which includes air flow and a balance of brown and green layers, odor should not be a problem.
Step 8: Place the wall on the front of the compost bin
Okay, let’s raise the wall in front. To keep the bottom bracket from resting on the ground, I turned the screw to engage the track on the 4×4. This means I can now feed in slices as long or low as I want for each stall. I would probably leave them all up while I fill them and let the compost set, but it would be very helpful to remove the strips while removing the compost for use.
Note: treated wood vs. untreated wood
If you’re concerned about using treated wood around your compost, know that the main ingredient in Prowood’s pressure-treated lumber is actually copper, which is used in pans and even water lines. The technical name is Micronized Copper Azol which still makes the wood termite fungus resistant but means you can use it on food preparation surfaces. This also means other benefits like a more natural appearance, less wear on fasteners, and color-treated boards will last longer than cedar and redwood boards.
Step 9: Protect the compost bin by adding lids
Okay, so the last item and project for this compost bin is going to be a cover, in order to keep the animals out, next I built some covers. This is a very simple build with some 2×2 fabric pieces and more hardware pieces. I built these inside my shop because it’s easier to do on a large surface than on the ground.
I started by attaching the fabric to one of the 2×2 pieces, then flipped it over and attached the long side to this short side. Then just repeat on the remaining two sides. Again, choose air flow but an area free of critters.
To attach it to the compost bin, I started by attaching some hinges to the back of the body. Then I screwed the cover into place, attached it to this hinge and then secured it with screws. No matter how long you have the front wall, this cover will be closed but let’s go ahead and install all the slats and take a look.
You can leave it exactly as is, but I installed a simple chain attachment with a small weight to make lowering the doors a little easier. I have finished! You’ve built your own compost bin!
I’m just starting to compost, so I know I don’t know a lot, but I think my three section compost bin is a rock! There are three bays because there are three stages of composting. I’ll always have one that I’m filling, one that’s in the cooking stage, and then one that will be ready to compost. It will be about two years before this third one is ready for use, but once I invest the time, I should always have a rotating kiosk in use.
It’s very easy to lower or raise the front wall depending on the task at hand, the covers will keep the animals out but allow moisture and air flow in, and unlike composting methods that require turning, I’ll be able to layer the green and brown stuff to let it sit until it’s ready. It is a very low maintenance compost bin.
****Remember I have a bunch of compost bin plans if you want to create your own. I have this large collection, but also the same design on a smaller scale. You can also go to prowoodlumber.com And find out where to buy Prowood for your next device. ****See you in my next project!
