An urban compost tumbler can be a great way to make compost for the urban gardener, particularly in areas where local regulations prohibit open compost piles. They are clean, unobtrusive, and sealed so they are relatively pest-resistant (with the exception of insects), and odor-free.
However, is a compost tumbler more efficient at producing compost than a well-worked open compost pile? Several independent studies suggest not.
To tumble or fork, that is the question…
One test was conducted using 5 different brands of tumblers and two conventional compost bins, one that was tended weekly and the other that was not tended at all. Each of the tumblers was tumbled three times a week while the tended conventional bin was turned with a pitch fork.
They assessed the quality of the compost after 5, 7, 10, and 14 weeks and found that the conventional bin gave well-rotted compost in 10 weeks, yet it took another month for any of the tumblers to produce the same quality compost. The compost bin that wasn’t forked took an additional four months to compost!
This wasn’t the only case of this I found in my research. All found the same result. A well-worked conventional compost pile is just as quick at making compost as a tumbler-style bin.
However, that being said, tumblers are much easier to work than turning a compost pile with a pitchfork. So, for some urban gardeners, a tumbler might be just the perfect thing for the garden.
There are four categories of urban compost tumblers:
- Crank-operated drums are the easiest to operate but are also the most expensive. They are usually high off the ground, making it easy to park a wheelbarrow under the hatch to empty them. The crank makes turning the drum very easy.
- Center-axle drums are harder to empty as they are generally lower to the ground. They can also get difficult to turn as they get full. Here’s a video for a DIY center-axle drum-style tumbler:
- Base rolling drums are usually very low to the ground and therefore quite awkward to empty. However, many people find them easier to tumble than the center-axle drums as these ones can be pushed with your feet. Here’s a DIY video for this style of tumbler and this one is off the ground, which might make it easier to empty:
- Roll-around spheres are great party conversation. They can literally be rolled about the garden as they are truly spherical. However, this style also makes them more challenging to turn when full and to empty.
If you are in the market for an urban compost tumbler consider these points:
Choose a style appropriate for you. Consider the styles I mentioned above and how you’ll be emptying it and turning it and select the style that will be most appropriate for you and your garden.
Think about the opening. Some tumblers have a round screw top lid, usually because they are made from recycled barrels. When the tumbler gets full this opening can deform slightly, becoming more oval in shape than round. This makes it difficult to thread the lid on. Dirt and other debris can also make threading the lid on difficult. However, once it’s on, it’s very secure. Alternatively, other tumblers come with a latched door lid, which are considerably easier to open and close.
With centre-axel tumblers, it’s also a good idea to consider whether two openings are better than one. Two generally make it easier to empty.
Give it a trial tumble. There is no shame in asking to give a tumbler a go with some weight in it before you make the purchase. After all, they are anywhere from $120 to over $300, so it’s not a minor investment. You simply won’t know how difficult it will be to tumble with a heap of moist rotting organic matter in it, until you try it.
Have brown materials handy. Once you have your tumbler home and have started adding organic matter, it is a good idea to have a bag of leaves, newspaper or some straw handy nearby. As these closed systems retain a lot more water than open compost piles, you will need to add about 40% brown material; otherwise you will end up with a slimy goo rather than rich ‘black gold’.
An urban compost tumbler is a great addition to the garden. However, be weary of claims that they will turn your refuse into compost in only 14 days. It would seem as though most independent tests indicate that they take just as long to compost material as a well-tended traditional compost bin does. However, that being said, they can be very easy to use and the closed containment system makes them even more appealing in an urban setting.