The drum is turned by means of a handle at the far end of the frame
Compost tumblers are available in three basic forms.
- The Rotating Barrels,
- Tombola drums.
- Rolling Drums and Balls
I have found that the speed of decomposing varies with the type of tumbler bin
as in practice the ease of rotation (see above) will play a major part in determining the frequency with which the bin is turned and aerated once the novelty of having a new bin wears off. At the Stokes Wood Allotment Demonstration site, we have
found that the barrel type of bin can be quite heavy to turn when in use which means that people do not turn it! On the other hand, the Jora “tombola” style is quite easy to turn and is spun regularly by small children.
These consist of a vertically mounted barrel or drum which rotates on a central, horizontal metal axle. The axle is mounted on a metal, wood, or PVC frame. As a rule, the plastic drum is made from recycled plastic but at
least one company reuses drums which have previously used by industry thus saving the energy which be used in the recycling the plastic in. When the bin is turned, and the contents tumble inside the bin the central axle breaks up and mixes the contents. It
is worth checking that the lid is correctly in place before spinning the bin.
In my experience the older bins of this type are one most likely to be sitting in a corner of the allotment neglected because the gardener could not get on with
it. Having said that I usually find that in a group of 50-100 gardeners in a Garden Club there will be one or two who get on well with this type of bin and use them to produce compost quickly and efficiently. One of the gardeners also reported success in using
this type of bin to produce leaf mould in the autumn.
It is also a good idea to save the compostable material and fill the bin all in one go (batch composting) as the compost needs to be at the same stage of decomposition, as it will all be tipped out
at the same time. While Barrel Tumblers are neat in appearance and resistant to rats and other pests do consider the storage of the material prior to composting and while it matures at the end of the tumbler process. The bin may be very heavy to turn
The different makes and types of tumblers are mounted at different heights, so it is advisable to check that it is a comfortable height.
There are advantages in having a bin that can be emptied directly into a wheelbarrow,
otherwise they can be emptied onto a sheet of polythene and contents shovelled into a barrow.
A horizontally mounted drum rests on a raised framework and look like a large tombola drum. The drum can
be either free spinning or crank-operated. In the latter case, a crank assembly is provided to turn the drum relatively easily, but this may be slower than the free spinning models. The drum may consist of a single or double chamber and will normally
have internal baffles to help mix the materials. With the twin-chambered models, material can be starting the maturation process in one chamber while fresh material is added to the other. However, a separate maturation bin is recommended for maximum production
and to make best use of the speed at which the material is broken down. They may have sliding or hinged doors. The are a number of low cost plastic models on the market as might be expected the dear metal models are longer lasting and more likely to be rodent
The Mantis range are examples of this type of bin sold for garden waste .http://mantis.uk.com/mantis-compostumbler-comparison.asp
The Jora range is
available for cooked food waste are available from https://www.quickcrop.co.uk/joraform-compost-tumblers.
The drums are mounted on a frame and this needs to be of a height that will enable a wheelbarrow to be placed under the drum and the compost
emptied directly into it. Some models are supplied with frames for wall mounting.
Base rolling drums.
Round or horizontally shaped drum design to be rolled on a ground-level base quite widely advertised. Depending
on price and style, these may be mounted on rollers, or have moulded raised points to suspend the drum so that it can rotate on the base. The type with rollers in the base requires less effort to turn.
Depending on the size of the composter, it
may be necessary to bend to turn it and emptying has to be undertaken using a spade. These are often sold for smaller gardens. However, if the drum can be rolled of its base it can then be rolled to the part of the garden where the compost is required.
Roll-Around Sphere or Barrel Compost Tumblers.
The commercially available models of which I am aware are large shaped “balls” that are rolled around the garden to mix and aerate the compost. They tend to be difficult
to steer and to empty. It is possible make a roll-around barrel composter using an empty chemical drum, drilled with air holes and fitted with a secure lid. An example of such a bin is shown on the "Demo Site" page