How to Build a Compost Barrel (With Photos)
If you’ve decided to begin composting, then you have two options, you can start a compost pile somewhere in your backyard or you can use a compost bin.
If you’ve decided to work with a compost bin, know that you can build your own bin rather than buying one at the store.
Doing so will save you a little money, but, most importantly, it can also be a fun weekend project using supplies and tools you may already have on hand.
The most difficult item for you to obtain may be a 55-gallon plastic drum that forms the main body of your compost barrel. Check with friends and local companies to see if they have one available. Before working with it, find out what sort of material it initially contained and clean it thoroughly and appropriately. If you have no luck getting a drum from a local supplier, you can order one online or from a local hardware store.
- 55-gallon plastic drum
- 1 sheet of plywood (1-inch thick, a few plywood scrap pieces also could be used)
- 1 hardwood dowel rod (1-inch width, not pine)
- Scrap wood (four 2x4s at least 40 inches long and others as needed)
- 100 inches of metal L-brackets (2-inch lip minimum)
- 4 hinges
- 4 locking latches
- 1 or more metal handles
- 1 roll of metal flashing (scrap pieces could be used)
- Power saw
- Power drill
- Drill bit
- Screwdriver bit
- Sheet-metal scissors
- Screws and bolts as needed (for assembly)
- Waterproof wood glue
Build the Frame
The frame of your compost bin will securely hold the barrel and allow you to rotate it regularly.
- Measure the diameter of your barrel (probably about 24 inches) and cut two, matching triangles from 1-inch plywood. Each side of the triangle should have sides 10 inches longer than the barrel diameter.
- Next, measure the length of barrel (probably about 35 inches) and cut two 2×4 support struts measuring 4 inches longer than the barrel. These will form the “long side” of your frame.
- Trim and notch the end triangle pieces to snugly fit the 2x4s.
- Three inches down from the top of the triangle, drill a one-inch hole through to hold the compost bin axle.
- Trim the top of each triangle off, bisecting the holes you just drilled. This will allow removal of the bin as needed.
- Strengthen the axle bed by installing support blocks on the interior side of the triangles.
- Secure the four frame pieces together with screws. You now have the frame for your barrel to rest upon.
- Add additional 2×4 struts on the inside of the triangles to strengthen the base of the frame.
- Assemble two “clamps” for each triangle out of your wood scraps. These clamps will secure the axle in place. Add a hinge on one end and a latch on the exterior side.
- Optional: Paint or seal your frame. Your rotating compost barrel will be left outside in the weather, so you should consider protecting the frame.
Creating the Hood
Adding material to your compost bin is easy when you have a simple hood. You’ll need to cut the hood space early to help you with installing other components.
- Mark a space on your barrel measuring 12 inches by 20 inches.
- Use a jigsaw to cut the lid out from the barrel.
- Stop Here: Install the axle and mixing fins next (described in sections below). When they are completed, jump back to this section.
- With screws, add flashing along three edges of the lid. This will keep compost material from falling out when you rotate the bin.
- Add hinges on the side without flashing.
- Add locking clips across from the hinges.
- While you’re at it: Install handles along the exterior of your barrel. You’ll grab these to spin the barrel.
Install the Axle
To rotate your compost bin easily, you need to add an axle to the drum.
- Find the center of your drum’s ends and drill a 1-inch hole in each.
- Cut eight 4×4 blocks from a 1×4 board. Drill a 1-inch hole at the center of each one.
- Insert your dowel rod through the first hole in your barrel. Before pushing through to the other side, slide two 4×4 blocks onto the dowel rod so they remain inside of the barrel. About six inches of dowel rod should protrude on each end of the barrel.
- With dowel rod inserted, sandwich each of the barrel ends with 4×4 blocks – one block on the inside and one block on the outside. Screw these pieces together with the barrel lid in-between.
- On the exterior blocks you just installed, slide two more blocks over the dowel rod and secure them with glue. These glued blocks will keep your barrel from sliding along the axle when turning the compost bin.
- Set the barrel on your frame. Trim the exterior-side of the dowel rod as needed, but leave enough for a 6-inch overhang on each side.
- Optional: Add an exterior dowel rod cap as desired.
- Optional: Apply wax to the axle to make turning easier.
Install the Mixing Fins
Mixing fins will turn and tumble the compost inside your barrel when you spin the barrel on its axle. Our L-brackets were made by cutting a rectangular aluminum tube into four pieces, but you may have your own idea for another material for this component.
- Cut four lengths of L-brackets to about 35 inches each.
- Pre-drill six evenly spaced bolt holes in the L-bracket.
- Notch each of the L-bracket strips in two or more places. The notches will allow the L-brackets to form along the curve of the barrel.
- Install the L-brackets with screws. Set them on a slight diagonal angle inside of the barrel.
- Optional: On the exterior, blunt the screw points or cap them.
Final Assembly of Your New Compost Barrel
With everything built, you can now set your barrel onto the frame and secure it there by latching the clamps. Your bin should spin smoothly on the frame and your hood should stay closed while it’s spinning.
Your Compost Barrel is Ready
Once you find a spot in your yard for your compost barrel, you can start filling it up with materials and add Ringer® Compost Plus® to supercharge production of microbes and nutrient development. Not long after that, you’ll have the makings of some great gardening soil!
Looking for more tips and ideas for your composting project? Safer® Brand has several articles, including:
- 7 Reasons Why You Want to Compost
- The Complete Guide on How to Compost
- Recipes for Great Compost
- Compost Tea for Your Indoor Garden
- How to Build the Perfect Soil Mix
- E-Book: The Secret’s in the Soil
Be sure to visit the Safer® Brand Community on Facebook, where you can share pictures of your new compost bin and ideas. Also sign up for a subscription to the Safer® Brand E-Newsletter for more inks to helpful articles like this one.