DIY Compost Tumbler

Many people believe that composting in an urban setting is a bad move. It’s true that you don’t want to lay out a picnic for rats and other undesirables, but there are some excellent ways to compost in an urban setting without smells, messes, and unwanted critters.  

One method of urban-composting that has become immensely popular is vermiculture or vermicomposting, where you basically keep a giant container of pet-wormies and feed them your food-garbage. The worm-method is supposed to be phenomenally efficient, gaining momentum even in uber-cities like New York. However, the types of worms that do best in in vermiculture are an invasive species, so if you intend on putting your worm-compost-soil in your garden… you’d better figure out a way to keep your wormie friends in your compost bin and not in the great outdoors.  

One worm-free option for urban-composting is to invest in heavy duty pre-made plastic composter unit. These come as free-standing units or as mounted “tumblers.” You can read reviews for yourself to see the pros and cons of each product. I’ve heard a range of opinions. Across the board, though, these units can cost a pretty penny and you’re lucky if you can walk away with one for under $150.  

Vermiculture doesn’t fit my composting goals, and the price-tag on the pre-made composter units was mighty steep…. so I set out to see what I could do DIY-style. And you know what? I managed to build my own tumbling compost unit for about $30!!! And the price could definitely go lower if I had put more planning into it.  

Overview: I used scrap materials we had on hand and found the rest (nuts, bolts, screws, locks, etc) at a local salvage yard. The most expensive elements were the barrel locks and spray paint, which were purchased at Home Depot. I used these plans and these plans for inspiration, but incorporated some of my own ideas. It’s a very adaptable project,  so there’s plenty of room for creativity. I must say, though, that it is probably a very tricky project without the necessary power tools… so if you don’t have them, buddy up with someone who does.  

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Instead of building a frame structure like in the plans linked to above, I built a post-and-beam version by sinking my two 4×4 posts in concrete footings. Using a special 2″ drill bit that cost $4 at Home Depot,  I drilled through the posts and the barrels. I then threaded the metal fence post through the whole shebang, and wallah. Here’s a doodle of the structure:  

Materials:  

• Two 4 ft lumber posts- (dimensions should be 4×4, but if you don’t have 4x4s, you can screw together 2x4s to get the necessary width.)
• scrap ply wood or 2×4 for “plates” on either end of barrel
• One 55 gallon plastic barrel (often given away or sold cheaply by soda-bottling companies or car washes)
• two door hinges
• two barrel locks (somewhat optional)
• One 4ft length of metal fence pole
• 6-8 heavy duty nuts and bolts
• 1 bag of quickcrete
• various screws (long)
• black spray paint (the kind that sticks to plastic)

Equipment:  

• Sawzall
• electric drill
• Miter saw
• 2″ boring-bit for drill

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Here are the steps in more detail:  

1. Rinse out your barrel. Mine was full of Mountain Dew syrup, which is okay for compost, but some barrels might have other not-so-nice things in them, like car wash soap.
2. Cut your flap door to your liking with the sawzall and re-install it with hinges and locks, etc.
3. Drill plenty of air holes throughout the barrel to allow for air circulation (which is essential for composting.)
   

   Huck carefully drilling holes in the barrel.

     

4. Install “plates” on either end of barrel with nuts and bolts. These “plates” will help distribute the weight of the loaded barrel (diagram below).
   

   Diagram of support "plates" bolted on either end of barrel.

     

5. Using your special 2″ drill bit for boring, drill hole through center of the sides of the barrel.
6. Drill holes through support posts
7. Sink support posts in ground. Level posts and pour concrete footings.
8. Thread your barrel on the metal fence pole, and the fence pole through the lumber posts….
9. Paint the thing black,  if’n'ya like.
10. COMPOST!!!

NOTE: Many people add a “fin” to the pole that runs through the barrel, which helps to break up compost as you turn it. I intend on adding spokes of some kind in the near future…. just haven’t reached that point yet!  

Let me know if you give this project a try!