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As composting becomes more popular among gardeners and homeowners, many different models of composters have become available in the marketplace. They range quite a bit in price and design, and some are simply not worth buying. Composting is a simple process, and so a composter should be simple in design.

When choosing a composter for your yard or garden, it’s helpful to group composters into two main types – bins and tumblers. Both types are effective at producing compost, but there are significant differences. Understanding the features and benefits of these two basic types will make it easier for you to choose the right composter for your needs.

Footprint

Both bins and tumblers take up about the same amount of ground space in the yard. The average composter will take about a 4 – 6 sq. ft. footprint. Compost bins are not meant to be moved, since most compost bins are open-bottomed. There are some bin models with a wheeled collection cart instead of the open bottom, but this is not typical of most compost bins.

Compost tumblers are also stationary for most models. There are some compost tumblers on the market that are designed to be rolled so the finished compost can be emptied directly on a garden bed, but this does not seem to be an important feature. A wheelbarrow works just as well.

Capacity

Compost bins have a larger capacity then tumblers, about 2 – 3 times the volume per footprint size. Compost bins commonly hold between 7 – 20 cubic feet of composting materials, depending on the model. Compost tumblers range between 4 – 15 cubic feet capacity. This is because the tumbler drum can be more difficult to spin under large loads.

There are some models of compost tumblers which have large capacity yet are easy to spin. The three Jora models, at 4.5, 9, and 14.2 cu ft capacity, are pretty easy to spin even when full. This is because the Jora is mounted horizontally on its axis.

Durability

Compost tumblers are more durable than compost bins. Tumblers are more heavily constructed since they need to be strong enough to hold the full weight of the composting materials. When choosing a compost tumbler, inspect the supporting legs and the central axis connection – they should be strong to hold up to years of use. If handles are provided for spinning the drum, be sure they are not flimsy. Some tumbler models do not have handles, they have indentations in the molded drum for hand grips. This works just as well as handles.

Compost bins are made using thinner plastic, since they only need to contain the composting materials rather than support the weight. The thinner plastic can become brittle in cold weather or after years of use and sunlight exposure, so care must be taken when removing the lid and when emptying the finished compost from the lower ports. The plastic can crack or chip with age or hard use.

Functionality

Compost bins are not really designed to make it easy for gardeners to turn (mix) the composting materials. It’s hard to get a pitchfork or shovel down into the pile and turn it effectively. Years ago, we earnestly tried to turn the materials in our bin, but eventually we gave up. It was too much work and we risked damaging the bin with the shovel. So we simply left the compost unturned. This results in less aeration so it takes longer for the compost to process. Depending on the time of year, it might take 2 -3 months for the composting process to complete.

With compost bins it can be difficult to access the finished compost using a shovel – the compost at the bottom is compressed by the weight of the material above and you risk chipping the sides of the port when trying to work a shovel through the port. A small hand spade would work, but this takes more time. With our compost bin, we found it easier to lift the entire bin off the compost and then use a shovel to separate the finished from the unfinished compost. The unfinished compost was then shovelled back into the bin. This method was a bit tedious but much faster than removing the compost through the bottom port.

Compost tumblers, by contrast, are designed to make it easier to turn the compost since you only need to spin the drum a few times every week or so. This is the central feature of tumblers – they speed the composting process by making it easy to mix the materials, and the sealed unit develops more heat which further speeds the decomposition of composting materials. With our compost tumbler, we cycle through batches in about 6 – 8 weeks.

Spinning a compost tumbler, however, is not always easy. With larger models, such as the 9 cubic foot tumblers, the drum gets very heavy when about 2/3 full. This is especially so if the drum is mounted vertically on its axis. The Jora tumbler models are mounted horizontally on their axis and are pretty easy to spin even when near full.

Compost tumblers are also easier to empty than compost bins…

Compost tumblers are also easier to empty than compost bins. With tumblers, the wheelbarrow can be rolled directly under the drum so compost can be dumped right in. This assumes, of course, that the entire batch is finished.

With both tumblers and bins, there is the issue of when to stop adding new materials so that the whole composter can “finish” and the compost can be removed. In our yard we eventually bought a second composter so one could be used for fresh materials while the other finished off. Today there are “continuous use” tumblers such as the dual-compartment Jora composters, which have two compartments. When one compartment is full, simply switch to the other side while the first compartment finishes.

Composting Time

Compost tumblers are designed to speed the composting process by providing improved aeration and heat to the composting materials. We performed a side-by-side comparison and found the tumbler finished off in about half the time of the bin. However, the bin holds more volume which partially accounts for the slower processing time. In our region we have cold winters, and our bin slows down considerably. The tumbler, by contrast, sends up a mist of warm air when opened in winter, indicating that the composting process is active.

We performed a side-by-side comparison and found the tumbler finished off in about half the time of the bin.

When a tumbler is spun, fresh materials are mixed with the seasoned (more composted) materials. This has the effect of slowing the process somewhat. A dual-bin composter is an improvement in this regard, since fresh materials are put in one compartment while the second chamber is finishing off. In general, our compost tumblers cycle a load in about half the time when compared to the bin.

The moisture level in a composter is critical to the composting process. Moist contributions such as kitchen scraps, wet leaves or fresh grass clippings need to be balanced with dry materials. In this regard, compost bins have an advantage: because they are open-bottomed, they drain excess water readily. Some tumbler models have drain holes in the drum, and also a collection chamber in the base to receive the “compost tea” which is an excellent fertilizer.

It should be mentioned that the key to optimizing the time it takes to process a batch of compost depends more on the carbon/nitrogen ratio and maintaining a damp, but not wet, moisture level than on what type of composter is being used. To learn how to balance the carbon and nitrogen components, read our Guide to Composting. To learn how to correct an overly moist compost load (a common problem), read our article How to Fix a Soggy Compost Pile.

Pest Control

Both bins and tumblers do a pretty good job of keeping pests out of the compost. Compost bins keep out raccoons and dogs, but rodents can burrow under the base and even nest inside where the ground temperature is warm and food is close by. We had mice in the base of our compost bin, but they weren’t really a problem.

Compost tumblers are 100% pest proof since they are fully sealed. The ground around the tumbler is clean and you wouldn’t mind walking barefoot to empty the compost keeper into the composter.

Odor Control

Both tumblers and bins control composting odors. When you lift the lid there is a distinct ‘composting’ smell, but it is not unpleasant. When the lid is closed there should be no foul odors coming from the composting process, regardless of whether you use a bin or a tumbler.

Cost

Compost tumblers are more expensive than compost bins. As a rough estimate, they are about 30% higher in price for the equivalent capacity. The tumbler models are also longer lasting since they are built more heavily.

In general, choose a composter that has few moving parts such as a rod and gear for spinning the drum or multiple “aeration spikes” which can be easily broken by a shovel or pitchfork. Your composter should give you many years of service if you choose a simple but robust model. Over time you’ll forget the extra dollars it may have cost, and you’ll appreciate having a reliable and sturdy composter for your garden.

Summary

Compost Bin Pros:

  • lowest cost for a composter
  • large volume for a small footprint
  • drain excess moisture more readily

Compost Bin Cons:

  • thinner plastic which can become brittle or chipped by tools
  • not as easy to access finished compost
  • can attract and harbor burrowing pests such as mice

Compost Tumbler Pros:

  • sealed, aerated drum speeds composting process
  • durable, robust construction will last many years
  • easy to access finished compost by inverting drum over a wheelbarrow
  • “continuous use” models keep fresh compost materials separate from finishing compost
  • 100% pest proof

Compost Tumbler Cons:

  • more expensive than compost bins
  • some models are difficult to spin when 2/3 full