Choosing the right compost bin can be confusing, simply because there are so many of them. To simplify things, ask yourself ‘How much will I be composting at a time?’ ‘Do I need to hot-compost?’ and ‘Do I want to compost food waste?’ and then take a look at the popular bin types below.
Dalek compost bins – simple, low-cost composting
If you only have a small plot and are content to make cold compost, a dalek bin may be for you. These get their nickname from their shape and black colour (although there are square and rectangular versions around too), and are the most common type of compost bin in the UK. Dalek bins are so cheap to make that councils have been known to give them away free, or offer them at a special low rate. You can find out if your council has an offer on by visiting DirectGov.
Dalek bins come with or without sliding front access hatches, but frankly it makes no difference – getting compost out of the little door is extremely fiddly. Since there’s no bottom on these bins and they weigh hardly anything, it’s usually easier to lift the whole thing off the ground leaving the compost behind.
Unless you set it up on hard standing or provide a mesh base, rats or mice may temporarily set up home in them, especially in winter. However, provided you stay clear of the ‘do not compost’ items, they shouldn’t stay for long. Just get the mix right, put the material in in layers, and leave it alone. As composting gets under way the material in the bin gradually shrinks, leaving more room for you to add fresh material on top. Once it is full, lift the bin off and put it down in a suitable spot nearby. Fork any uncomposted material off the top of the exposed heap into the bin to start the new heap.
By the way, if your council runs a ‘free dalek bin’ offer, do get one. Even if it’s not suitable for your composting needs, dalek bins are perfect for making leaf mould.
Green Johannas and other large simple compost bins
If you produce a bit too much composting material to use a dalek bin, larger versions exist too. Some of these come with a base to make them rodent-proof, which means that you can compost cooked food waste in them too. A good example is the Green Johanna, which is quite a bit bigger than most bins and has a strong perforated base plate, making it completely rodent proof. The larger size means that it can be used for hot composting as well as cold, and you can buy an optional (but pricey) insulating ‘duvet’ if you want to keep your compost going during the winter. The one drawback to a Green Johanna is that you can’t lift it out of the way like a dalek bin – you have to use the hatch to get the compost out, which is quite fiddly.
New Zealand compost boxes
New Zealand boxes are a clever variation of a large simple composting bin that make composting large volumes of material very practical. They are actually two or three box-shaped lidded bins, usually made of wood, joined together with removable boards making up the front side.
The New Zealand box works like a compost conveyor belt. You start your compost heap at one end, adding material in layers as usual, and when it is time to turn it you just shovel everything into the next bin. This is made easier because you can remove the boards at the front one at a time. When the contents of the second chamber are ready to turn again you shovel them into the third bin, by which time they should have cooled down and can be left there to mature.
New Zealand boxes can be bought ready-made and are very simple to put together, but you can also make your own. There are some rather confusing composter plans at Garden Organic, and a much more robust version on the Food For Health Scotland website (which sadly omits the need for lids). Whatever you do DON’T buy a box made from treated timber. Manufacturers are keen to deliver a long-lasting product, and aren’t too bothered about what toxins may end up in the compost you make.
Tumbler compost bins
A compost tumbler is a box or barrel-shaped container raised up on a framework that allows it to be rotated. It is designed specifically for hot composting. You add ingredients in the same mixture as usual, but you don’t need to worry about layering them. Just spin the bin a few times every day, and it mixes the compost for you making sure that there are no dry edges or unmixed corners. This may seem like a lot of work, but it’s MUCH easier than turning a heap with a fork! Tumblers are also vermin proof, so you can add cooked food without worrying about it.
Tumbler compost bins are used to take a batch of compost through the hot phase of the process in as little as three weeks. At the end of this process you empty the bin, ready for the next batch to go in. Made properly, the compost it produces should be free of viable weed seeds and diseases, but it’s still not finished. It needs to rest for a few months to allow worms, fungi and minibeasts to turn it into the lovely crumbly material we’re all used to seeing. This means putting it into a regular compost bin, with a lid or cover to keep the rain out, for a few months. Alternatively, immature compost can be spread on the surface of the soil as a mulch so that it can finish composting there, but it shouldn’t be dug in.
Compost tumblers are not always the easiest things to load or empty, so take a good look at the design before you buy – you need a good, wide opening that isn’t too high to load into. It’s also worth mentioning that although tumblers are only used for hot compost, most of the ones on the market are not insulated. This is fine in high summer, but most of them don’t hold enough compost to stay really hot at cooler times of the year. This seriously limits their use, so make sure you get one that’s described as insulated or double-walled. If not, you will need to buy or make an insulating compost jacket (also called a compost duvet) to compost in cooler conditions.
Bokashi compost bins
Bokashi bins are not a complete composting solution, but they are a good strategy to cope with kitchen waste if space is limited. They are very popular with urban homesteaders, and with people who want to compost their kitchen waste but don’t want the work of making hot compost.
The basic idea is that you sprinkle ‘Bokashi mix’ (bran, inoculated with a patented ‘Effective Microorganism’ culture) over your food waste in a small bin, the size of a compost caddy. Over the next several weeks the food, instead of rotting, undergoes a controlled fermentation right there in the bin. Each time you produce more waste it is added to the top and sprinkled with more of the Bokashi mix, and when the bin is full you put it away for a couple of weeks to finish fermenting. You need a second bin to use in the meantime. When the Bokashi bins have rested for two weeks they won’t contain finished compost, but the food will have broken down to the point where it will no longer attract vermin. This means that it can safely be buried or added to your regular compost heap.
Bokashi bins have a yeasty, fruity odour which is evident whenever you lift the lid to add more material. The smell should never be unpleasant, but problems can occur if you don’t follow the instructions carefully. The crucial point to avoid bad smells is that the food waste should be chopped up, and then pressed down fully to compact it so that the air can’t get at it.
Worm bins are an alternative means of turning food waste into highly concentrated compost. The amount of material they can deal with depends on the size of the bin. For a simple version that is free to make, visit our tyre stack composter article.