Best Compost Bin of 2021
The Lifetime 80-Gallon Rotating model is the big enchilada of self-contained rotatable compost bins, and it easily takes the cake as our favorite model. This compost bin has one large chamber with a support bar running through the middle, which has holes for additional aeration. It rotates easily and has multiple grip points to assist with turning. This tumbler is the only model we tested with an easy-to-use locking pin to prevent it from rotating. Our favorite feature is the huge door that you can open from the top and easily shovel in leaves or whatever material you're using to balance your carbon-to-nitrogen ratio, or to throw in some fresh food scraps. When it's time to reap the fruits of your labor (actually, the microorganism's labor), you can open up the door and dump everything on the ground for distribution in your garden beds. Easy peasy.
This beast takes a while to assemble, and we strongly recommend having a power drill on hand for the many, many fasteners that hold everything together. While assembly is tedious, it isn't difficult. The instructions are very easy to follow, and the parts are well organized and clearly labeled. We believe the final product is well worth the time spent putting it together. This bin may be too large for apartment dwellers or other folks with limited space, but it's fully capable of producing high-quality compost while keeping the elements at bay and small critters out.
The Miracle-Gro Small composter is a fully contained and compact tumbler, ideal for rooftop gardens or situations where space is at a premium. For the price, it's a great way to venture into the sweet science of composting, especially if you want to teach and share the experience with youth. Assembly takes a little time, but all the plastic pieces snap together without too much effort, and no tools are required. Once assembled, the tumbler spins easily unless you flip a switch to lock it in place. The switch is a little flimsy, but this model isn't very large, and it doesn't take much to stop it from rotating. A generous amount of holes on either side ensures good aeration, and while the door isn't huge, it's big enough to add food scraps and amendments with a small trowel.
Our main beef with this little tumbler is the sliding door. If you aren't careful it can get stuck in its sliding tracks, especially if dirt gets in them — which it will, since the door is fairly small. It's likely to get leaves, sawdust, or whatever carbon amendment you're trying to shovel in there. This door is hefty enough to keep out mice, rats, and squirrels, but an enterprising raccoon could likely pry its way in, while a bear could easily crush the whole bin. We suspect most folks who order up this small compost bin won't have any bears to deal with and will appreciate the lightweight Miracle-Gro Small.
If you have some cooped-up kids in your home, the FCMP Outdoor Hotfrog could be a great way to get them outside, where they can get some exercise while learning about the natural phenomenon that is decomposition. This simple composter can be turned on its stand, but it's also perfectly fine (and more fun) to roll it around the yard. The Hotfrog arrives completely assembled. All you need to do is unbox it and place it outside on its stand and you're ready to go. It has a few aeration holes, and despite our concerns that they would become clogged and prevent any aerobic decomposition, the Hotfrog churned out compost just fine.
While a lack of moving parts keeps this compost bin durable and tough, it can be difficult to turn as it becomes full. It will turn on its stand, but the whole thing is pretty close to the ground, and turning it could be hard on the back. It might be best to have some kids push it around the yard. Having a little space for it to roll makes this model easier to use, too. The door slides much like the Miracle-Gro composters, but it is made out of thicker plastic and it slides open and closes more easily. We just wish it was wider. If the assembly process of other tumblers seems daunting to you, the Outdoor Hotfrog is an excellent alternative.
For those living in a yardless apartment or who need a little compost in the dead of winter, the SCD Probiotics All-Season Indoor compost bucket could be what you're looking for. Mind boggled by the 30:1 carbon to nitrogen ratio? No need to worry about that with this composter. You're provided with a bag of Bokashi to get the party going. Bokashi is a "compost starter" that creates an anaerobic fermenting process, which is why it works in an airtight bucket. Layer your food scraps with the included Bokashi starter, seal up the lid, and in about a week you have a fertile compost tea that's easily dispensed from a spout at the bottom. Then you can pour it in your potted house plants for a nutritious boost.
The simple instructions included with the SCD bucket don't quite represent our experience in making compost tea. They suggest we'd have usable compost tea within 3 days, but we didn't extract any tea for about a week. The instructions also say that we might see white mold growth, which is fine, but that smelly blue-green mold is bad, and if it's present, then we'd need to restart the process. After a few days of composting, we opened the bucket for inspection and saw lots of fuzzy white growth, accompanied by an unpleasant smell. After consulting with some friends who've used this process before, we learned the smell was standard, as was the white stuff, and we decided to press on. We're glad we did because compost tea is great for our plants. Unfortunately, there are still a lot of food scraps left over after the fermentation, and if you don't have another way of further composting these leftovers, then you'll need to throw the leftovers out or bury them. In short, the SCD bucket is a fun, odor-sealing science experiment your house plants will love, but it can't eliminate all the food scraps coming out of your kitchen.
The Miracle-Gro Dual Chamber one-ups the competition with two independently rotating chambers. While one chamber churns and burns with microorganisms digesting your food scraps, the other chamber can remain static as your finished compost cools down and stabilizes so it can be used in your garden. A chamber for curing isn't really necessary, as once your compost reaches maturation, it is unappealing to animals and bugs, and only gives off a low-key musty smell. So, you can always leave it exposed in a pile in your yard. It is, however, nice to have somewhere for curing if there isn't room in your yard or if where you live doesn't allow tarp-covered dirt piles. Both chambers have a locking tab that makes sure they won't rotate when rotation isn't desired. Assembly is just like the single-chambered version we tested, you just need to do everything twice. The plastic parts snap together fairly easily to create a surprisingly solid little tumbler. If your composting ambitions are bigger than the 18.5-gallon single-chamber Miracle-Gro Small, this one is exactly the same, but with twice the capacity.
Not to sound like a broken record, but our major complaint about this model is the size and operation doors. Herky and jerky as you slide them open and closed, these doors are hardly big enough to accept a small bucket of food scraps. You'll need to shovel that slop in with a trowel. If you're looking for a medium-sized composter that will remain easy to turn even as it reaches capacity, we recommend this one over the single-chambered version, though it is a bit more expensive.
If you have a small yard and a shovel, the Algreen Soil Saver is an easy way to get your compost on while keeping it protected from skunks, squirrels, and rats. It's like having a big trash can without a bottom. 3 access doors slide up so you'll be able to shovel out and spread your finished compost. The entire top comes off, making loading a very easy process, and there's plenty of room to maneuver a shovel or pitchfork to turn your pile. The Algreen Soil Saver contains the unsightly mess of a compost pile while the microbes do their job.
Because you'll be composting directly onto the ground, this model isn't leakproof, and if your ratios aren't correct, smells will be more apparent than with one of the self-contained tumblers. As far as security goes, a large dog or a bear could easily knock the Soil Saver over and feast on its rotten contents. Turning this composter will require a pitchfork and some sweat equity but may result in a more even and thorough mix than a tumbler.
To use GEOBIN Expandable 216-Gallon, you'll need a pitchfork, perhaps a tarp, and plenty of space. This bin is actually a roll of plastic mesh that can create an enclosure capable of containing up to 216 gallons of compost. The high walls will discourage pets and children from messing with your compost, but mice, squirrels, and all sorts of bugs will have free access. Because the enclosure is open on the top and bottom with plenty of holes in the mesh, lack of aeration is not an issue here. Our testers didn't love this composter but feel that it's a great way to store leaves to add to compost throughout the season.
This design does not protect your compost from most animals, and there is no odor containment. The walls are just over 3 feet tall, and we found it easiest to just detach the plastic clasp that holds the bin together to gain proper access for turning. Some strategy is required for setting this one up. It's good to have a healthy amount of leaves or grass clippings ready to fill the majority of the enclosure from the get-go since if there isn't any material to weigh the fence down, it can easily blow over. If you have a big yard and a lot of leaves and kitchen waste, this huge, expandable fence could make a nice boundary for your compost pile.
The Squeeze Master Large Compost Tumbler offers a nice alternative to the larger models, and its dual chambers allow a safe and secure place for your compost to cure. Once your compost has reached maturity, it will need to cure, and while it's curing, you can't add more food scraps. This model lets you keep the party going. When one batch is ready, you can start a fresh batch in the second chamber. This composter takes a bit of time to assemble, and you'll need a screwdriver and a socket wrench to tighten all 56 of the tiny fasteners, but the instructions are clear and our testers found the assembly to be fairly easy.
Each 21.5-gallon chamber has a small, flimsy plastic sliding door. This makes it difficult to add scraps to your compost and even more difficult to remove all the finished compost from the bin. The doors are secure enough to keep small animals at bay. The chambers don't rotate individually, so when you turn your active compost, you turn your curing compost. This isn't a huge deal, but it's better for curing compost to remain static while it cools and the composting process winds down. If curing compost out in the open isn't an option where you live, the Squeeze Master might just do the trick.
The Bamboozle Food Composter is a nice place to store food scraps in your home for a few days before taking them outside for composting. The lid has a carbon filter, and despite having no latching mechanism on the lid, it contains odors fairly well. This little bamboo bucket is compact, so it's easy to keep under the sink, and sits nicely on the counter, ready to accept onion peels and other scraps while you cook.
To call this container a "composter" is a misnomer. Its capacity isn't large enough to compost a reasonable amount of material. If you filled this bin following the proper composting carbon-to-nitrogen ratios, you'd end up composting very little kitchen waste. We found it best to use it as a temporary storage container for your scraps. And we mean temporary, since leaving scraps in this bin for more than two days quickly led to a smelly, moldy mess. The lid is easier to remove than that of a 5-gallon bucket from the hardware store, and the Bamboozle fits nicely under most sinks.
Why You Should Trust Us
Lead tester Matt Bento's first forays into compost began in high school when, during an attempt to reduce existential dread about the health of the planet and become more environmentally friendly at home, he nailed four pallets together and declared it a compost bin. Using an unlimited supply of dried grass clippings, he achieved the perfect carbon to nitrogen ratio of near 30:1, produced steaming hot compost, and became fascinated by decomposition. In college, he designed a large-scale composting program for his school cafeteria after a considerable amount of research, visiting composting programs at universities and prisons across North Carolina. He'll be the first to say that small-scale composting at home is a lot more fun and more forgiving than trying to manage a university-sized waste stream. Today he composts for the fun of it, and he loves seeing his household garbage turn into food for his garden.
Composting doesn't have to be complicated or require special tools. A tarp, a shovel, and a good supply of dry leaves, grass, or sawdust are all you need to produce great soil amendment and reduce waste from your kitchen. However, many folks don't have space in their yards for a large open compost pile, plus neighbors often don't appreciate the smells of a compost pile before it's completed its decomposition process, while mice, possums, and flies find it particularly attractive. A compost bin limits how much you can compost but creates more opportunities for where you can compost. A good bin needs to offer an easy way to turn your compost, some way to aerate the compost, contain odors and deter pests, and be easy to load food scraps and unload the finished product.
We identified four metrics for evaluating composters; turning, loading, aeration, and odor containment. Additionally, we factor in ease of assembly, since assembly is fairly involved for some models and a non-issue for others, but has little to do with how well each model produces compost. We made compost with each model, following the provided instructions and using food scraps from our kitchens and yard wastes from our yards. While almost every model in our review is fully capable of generating composted material for your garden, some proved much easier to use than others, and there are clear winners in terms of ease of use and how well they contain odors.
Analysis and Test Results
After thorough testing, we compared our notes and experiences. We scored each product relative to the other models in the review to create a comparative assessment of the bins we reviewed. Below, we highlight the top performers in each metric so that you can select models that fit your specific needs best.
Loading (and eventually unloading) your composter is an almost daily task and the most common interaction you'll have with your compost bin. If it's easy, you'll happily leap out the door to load food scraps into your bin. If loading is difficult, it becomes a chore — meaning you may procrastinate, leaving your food scraps to mold. The GEOBIN Expandable is essentially a boundary for your compost with a completely open top. Hence, it's the easiest model to load. Simply throw your food scraps in and stir them with a pitchfork. To unload, merely detach the fasteners to disassemble the whole bin and distribute the finished compost as you see fit. We love the easy access, but so do squirrels, mice, and other rodents. The Algreen Soil Saver has a large lid to discourage animals and is as easy to load as the GEOBIN, plus it has 3 panels at the ground level that help with unloading.
Among the fully contained rotating bins, the large Lifetime 80-Gallon Rotating bin easily takes the cake. It has a huge lid with robust, functional hinges and latches. We love how we can remove the top of the bin, dump in entire shovelfuls, and rotate the bin to completely dump out all the compost. The opening is even big enough that we could turn the compost with a shovel to inspect how it's coming along. The Miracle-Gro models have smaller doors, but they're appropriate considering the size of the containers, while the Squeeze Master tumbler has very small doors that make it very difficult to unload all the compost once it has matured.
Turning your compost is a critical task that ensures your compost is receiving the proper amount of oxygen so that the microorganisms can complete their aerobic decomposition process. For a traditional "compost pile" that sits on the ground, you can use a pitchfork every few days to churn things up. Several of the self-contained bins we tested rotate on an axis, making it easy to turn the compost while it remains in the container and not all over the ground. Once these containers start to get full, turning becomes more difficult, but some designs offer solutions to make turning easier.
The Lifetime 80-Gallon Rotating tumbler gets top marks for turnability, providing several grip points to help with turning as it becomes full, and a locking pin to keep the bin right-side up, upside down, or whatever configuration you like. The Miracle-Gro models have a much smaller capacity and spin easily even when they are full. They also feature a small plastic tab to prevent undesired rotation.
The FCMP Outdoor Hotfrog has the most unique (and fun) way of turning. It rotates freely on its stand, but the best way to turn this bin is to roll it around your yard. This is also a great way to get kids excited about composting. The Hotfrog has a pretty large capacity, and even on its stand, it still sits very low to the ground, so it's not the best choice for folks with mobility issues.
If you never turn your compost and it doesn't get much oxygen, you'll still get usable compost eventually. Proper aeration will get you usable compost much more quickly. Aeration is key to maintaining the aerobic process by which microorganisms break down food waste; therefore, you don't want your compost sitting in an airtight box. The GEOBIN comes out on top when it comes to aeration since it's an open-air plastic fence, but the other bin designs provide aeration and some security from bugs and rodents.
The Lifetime gets extra airflow into the bin with air holes incorporated into the axle it rotates on, and if you don't load up this 80-gallon behemoth to its max capacity, there is lots of room for air to flow when you rotate the bin for turning.
The Miracle-Gro bins feature 12 small holes on the sides of each chamber to increase airflow. The Miracle-Gro Dual Chamber has two independently rotating chambers, so as the compost gets close to maturation, you can start rotating a new batch in the chamber next door while the old batch cures, unrotated.
The Hotfrog tumbler has some small holes on the side for aeration. Our testers had some concern that these holes were too small and would become clogged, especially since they used fine sawdust as a carbon amendment. Much to our surprise, the holes remained unblocked throughout the process. While the Hotfrog doesn't have the best aeration, we were able to get good compost from it.
The SCD Probiotics All Season Indoor breaks down food wastes via fermentation, which is an anaerobic process. To work properly, this bin needs to be air-tight so the Bokashi compost starter can do its thing, and also to prevent the smell from permeating your home.
Odor Containment and Security
If you are a scientifically precise composter whose carbon to nitrogen ratios are perfectly balanced at 30:1, odors won't be much of a problem once your compost is churning and burning. For most of us, some experimentation will be required to hit the perfect balance, and there will be some periods where our compost pile will be a pile of rotting food, which is very attractive to raccoons, squirrels, mice, possums, neighborhood dogs, ants, and flies. A self-contained bin is much more forgiving and can protect your pile from small animals while you dial in your ratios, while somewhat containing odors that might offend your neighbors. The less space you have for composting, the bigger the problem odors can be. We tested odor containment by putting a rotting piece of pumpkin in each bin for a few days and then conducting some comparative sniffing. This produced stronger smells than normal active compost.
For truly odor-free operation, the SCD Probiotics All Season Indoor is the only way to go. Its airtight lid keeps order out of your home, and since it's meant to be used indoors, animals won't be a problem. The downside is that this composter is very limited. It can only process a gallon at a time, and since it uses a fermentation process, you'll be left with plenty of organic matter that will still need to be composted in a traditional way. You will get great compost tea for fertilizing your house plants, though.
While not really suitable for actual composting, the Bamboozle Food Composter does do an admirable job at odor containment. Its lid isn't airtight, but it has some air holes with a carbon filter. We couldn't smell anything with the lid on, even when we neglected to empty it for a few days and smelly mold grew all over the food scraps.
Browns (carbon) for your compost:
-Dried grass clippings
-Pine needlesGreens (nitrogen)
-Fresh grass clippings
-Fruit and vegetable scraps
-Horse or cow manureFor more info on what can and can't go in the compost, plus plenty of helpful composting tips, NC State provides an excellent composting resource.
For the outside bins, the Lifetime composter proved very secure, sitting high off the ground on its stand, and featuring strong aluminum latches. We feel confident this bin will keep your compost safe from curious animals, aside from bears. However, during our experiments with rotting pumpkin, we were able to detect smells from about four feet away. When your carbon to nitrogen ratios are balanced, this won't be an issue. The Hotfrog tumbler is also a very secure model, constructed from the thickest, most durable plastic of any bin we tested. It has a long sliding door, and we'd be very impressed with a raccoon that could open it. The Miracle-Gro bins have thin plastic sliding doors. While a large animal could possibly crush the entire bin for its contents, it is impervious to rodents and all but the smartest raccoons.
The open-air GEOBIN provides very little protection from animals, bugs, or even the elements. If you're concerned about rodents or odor, do not purchase this compost "fence." If it isn't held in place by a large compost pile, it can even blow away in high winds.
How long it takes to assemble your compost bin has little effect on how well your bin can make compost, unless you never get around to putting it together. As mentioned earlier, you can make compost just fine on the ground. However, we understand some folks don't have the time or patience for involved assembly processes, plus they bought a bin to make composting easier, not because they want to spend an entire afternoon putting a bin together.
As much as we love the Lifetime 80-Gallon once it's assembled and ready for action, we have to concede that the assembly took almost two hours. The parts are clearly labeled and the instructions easy to follow, but the process is long, and you'll want a power drill as you secure each plastic panel together with the many included fasteners. Also, you'll want to make sure to assemble this bin outside, since once it's put together, it's too big to fit through a standard door.
On the other end of the spectrum is the Hotfrog, which arrives completely assembled in its box. It consists of three parts: the tumbler, its stand, and the detachable sliding door. While it's not the easiest bin to turn, you can start composting minutes after it arrives in the mail. The same goes for the SMC Probiotics Indoor Composter. Just layer your food scraps in the bin with the included Bokashi compost starter, seal it up, and you'll have nutritious compost tea for your house plants in about a week.
The Miracle-Gro compost bins are constructed from plastic panels that snap together, a relatively simple process that takes about half an hour and results in a surprisingly solid bin. If you're intent on having a bin that rotates on a stand but wary of complex assembly processes, the Miracle-Gro Small and the Miracle-Gro Dual Chamber are both excellent choices.
The compost bins in our review offer a wide range of solutions to the problems faced by the urban gardener who has a surplus of ambition and a dearth of space. You can create a steaming hot pile of compost with the huge 80-gallon Lifetime composter, and folks in tiny apartments can glean an extra something for their house plants from their food waste with the SCD Probiotics All Season. Either way, composting is a good way to be a little greener with your food waste and a fun biology lesson for the whole family.
— Matt Bento