Compost bins and what to look for

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Compost bins

Also: If you want a compost bin, what are the options?


How does a compost bin work?


Are plastic compost bins any good?

There are so many types of compost bins out there that some may wonder which is the best type for them. Don’t allow yourself to become confused by the range of offers. Just be aware that all compost bins are very basic technology and that it’s not difficult to get organic material to rot.

However, a choice has to be made when sifting over compost bins when finding a bin that suits you. When selecting a compost bin, most people are persuaded by a combination of appearance and practicality.

The first thing to mention is that you may not need a compost bin at all. Depending on the type of garden you have and how you feel about the subject of making compost, you may find that you can accumulate a heap of organic material in an open space. There’s nothing to say that compost can only be made when it’s in a compost bin.

Do we need compost bins to make compost?

A stand alone heap will work by itself with the minimum of interference other than being continually added to. It will help the composting process if you turn over the heap occasionally but it’s not entirely necessary. I’ve seen some really good compost made in an open heap that’s been left to stand in one place. It takes longer to rot down into compost if you don’t turn it but it will always get there, eventually. It depends on how long you want to wait.

Modern compost bins are all about containing relatively small amounts of organic composting-material in one place. For the average house this is more convenient and usually turns out to be tidier and more hygienic.

The fact that you’re interested enough to investigate compost bins suggests that you understand the reasons for making compost and, most likely, the methods involved to make compost in compost bins or in an open heap.

Here, we want to explain the different types of compost bins that are out there. There are many interesting ideas in the world of compost making but you will find that most compost bins, especially the static types, do much the same thing.

If you want a compost bin, what are the options?








Home-made compost bins can be the cheapest way

The main reason why people prefer compost bins for making compost is that they contain organic waste in a tidy and convenient place. In a compost bin the organic waste is allowed to build up to a mass that’s big enough for the composting process to be fully effective. Organic waste doesn’t turn into compost, as we would like it to, if it’s spread out.

So, whatever home-made arrangement you set up, creating a capacious vessel that will allow the organic material to pile up, rather than spread out, has to be your main objective.

One favourite way of constructing home-made compost bins is to use old wooden pallets. If you’re lucky you may be able to scrounge some disused pallets out of a skip somewhere; it will be wise to ask before taking.

If you can find some pallets, try to get 5 or 6 to make a good-sized compost bin set up. All you need to do is to tie them together to make a box-like assembly with either an open side or closed in.

The advantage of using wooden pallets is that there’s plenty of air movement through the gaps between the wooden boards. The compost that you make will need plenty of air. This is a requirement of all compost bins.

Plastic barrels can be converted into compost bins

This is another home-made option. If you can find a source of plastic drums for cheap or perhaps free, these types of containers can be turned into compost bins by applying basic modifications. Drilling some holes in the base will allow for the necessary drainage. More holes can be drilled to allow air to get into the material that needs to convert to compost.

You could buy or acquire a plastic bin, perhaps with a tight-fitting lid, that can be converted into a compost bin by drilling holes in it. This may work but a mistake that some people make is that the bin may not be big enough to allow for the organic material to build up over a long time. A small compost bin will fill up quicker than you may think.

Are plastic compost bins any good?

The most popular compost bins are made from plastic

Most compost bins are made by plastic moulding; usually rotationally moulded. Almost all compost bins that are made from plastic are used in the same way.

Modern plastic compost bins are designed to be big enough to take the kitchen waste from an average house and allow for it to be left for long enough for it to turn into compost. It may take up to a year to fill a compost bin, possibly longer. During the filling time, the earlier-added material will be in a constant state of decomposition or rotting. As material rots it will reduce in volume, taking up less space.

How does a compost bin work?

A compost bin will work with a minimum of effort. The procedure is, simply, to throw fresh organic waste in at the top and then, when the compost is ready, remove the finished-compost from an access door at the base of the bin.

The level of material in a compost bin will rise when you add fresh waste but will, slightly, drop down before you add the next fresh addition. The net gain upwards will be slow and become slower as the compost bin becomes more full.

When a compost bin is full, given that it’s taken a year-plus to fill it, you should be able to extract finished compost from the sliding door at the base that most plastic compost bins have.

When you slide up or remove the door you should see a wall of solid black and crumbly material. This will be the compost that you’ve been waiting for. Using a garden spade or trowel, you can dig out the black compost and either store it for later use or put it to use around plants straight away.

When you remove compost from the base of a compost bin, it’s quite likely that the material above will cascade down. When this happens inspect the material that drops and assess it. If it doesn’t look like finished compost then you need to leave it where it is and allow it to rot down further.

It’s at this point, where the cascading process happens, that making compost in compost bins, starts to become efficient. When the material in a compost bin starts to drop down, it will create enough movement throughout the whole mass of all that’s in the bin. This movement will be enough to allow air into the rotting mass. Getting air into a rotting mass of organic material is one of the best ways of generating compost.

When you remove compost from the base of a compost bin the whole amount above may take a few days to drop. Modern plastic compost bins are, generally, designed to be conical. That is, they are wider at the base than at the top. Moulded plastic compost bins are, essentially, a large conical tube with a lid on it. So don’t be surprised when material starts falling down when you start digging out compost, it’s what you need it to do.

The drop will make more space for fresh waste to go in at the top, while everything below will be in a state of advanced and accelerated decomposition.

Plastic compost bins have lids to keep out excessive rain water and reduce excessive drying. If compost is too wet the air can’t move through the mass that we want to turn into compost. Excessive wetness leads to stagnation. Apart from that if the contents of a compost bin is being constantly washed with rain-water, the nutrients that we want from the finished compost, will drain away.

Conversely, if we allow the material in the compost bin to become too dry, decomposition won’t happen. To make successful compost we need some moisture but not too much. Having lids on compost bins is the most effective way to achieve the right conditions for efficient composting.

Plastic compost bins are usually designed to be open at the bottom so that the first organic waste that’s deposited will be in contact with the ground or, ideally, soil.  The whole range of bacteria that’s available in soil will migrate into the kitchen waste. Most of the bacteria that’s in soil will play a big part in composting as it is these that will feed on and break down organic waste.

The plastic compost bins that you buy tend to have no air holes in the main body. Compost needs air for the composting process to start and continue but this doesn’t mean that plastic compost bins need to be like a colander full of holes. The lid on a modern plastic compost bin will be snug-fitting but it won’t be airtight. Enough air will find its way in to allow for effective composting. Added to that, the lid will be lifted regularly when more fresh organic waste is added. Plastic compost bins with their provided lids would not allow a sealed environment which would preserve foods or any organic material.

Most people notice that, when making compost, one of the easiest things in life is to get things to rot and one of the hardest is to keep things preserved.

Wooden compost bins

Wooden compost bins will be just as effective at making compost as any other compost bin. Much is made of the fact that the gaps between the wooden slats, whether designed or otherwise, will assist with composting. Then the point is made that the openness that comes with wooden compost bins will be detrimental to composting because heat will be lost, compared with plastic compost bins.

Air getting into a mass of compost will always be a good thing. The point about heat escaping is a non-issue. Heat will be generated when you make compost in any of the compost bins that are out there but that doesn’t mean that heat is a necessary part of composting.

Hot or cold, organic material will rot down. It’s true to say that if the heat that composting generates is contained within a compost bin, the composting process will be completed earlier than if cooling is allowed. But the quantities of organic waste that you will be handling in an average home will be small.

The mass of material that you bring together, when regularly loading small amounts of organic waste into a compost bin, won’t be significant enough to make any difference regarding temperature.

So, if you like the look of wooden compost bins, get one. They are more attractive to look at, compared to some of the basic plastic bins. Wooden compost bins will blend in anywhere. There’s no disguising plastic compost bins but makers of wooden compost bins can exercise artistic licence. One favourite style that’s out there are the wooden compost bins that are designed to look like beehives.

The compost that you make in wooden compost bins of any style will come out as good quality and will compare favourably with any other static-bin system. The only downside is that the wood in wooden compost bins will need to be treated with a wood preservative to prevent it from rotting and becoming part of the compost that you want to make.

If you have a treasured ‘beehive’ compost bin, you may find it worthwhile to empty it completely once in a while so that you can clean it before painting it over with wood preservative.

Hot compost bins

It’s always been known that when organic material rots it generates heat. Hot compost bins, also known as hot bins or hot composters, are designed to hold in as much heat as possible to make use of the generated heat. Hot organic material that’s transitioning into compost will do so, faster.

Hot compost bins are constructed using insulation measuring 50mm thick, or more, whereas basic compost bins that allow for a cold rot measure barely more than 3mm.

It’s claimed that hot compost bins will convert organic waste into usable compost in 30 to 90 days whereas the cold rot in a basic compost bin, with no insulation, may take about 6 months.

I would question all of this. I’ve never tried using a hot compost bin, I don’t see the point of the extra expense of the insulated walls and, to me, the temperature gauge can only be for academic reasons.

The heat that’s generated from a mass of organic material, will be finite. Organic material in a hot compost bin won’t provide a source of perpetual heat. While the initial heat retention in hot compost bins will get it off to a good start, there will be a point where everything will cool down to a cold rot and the process will eventually go through to completion.

From 30 to 90 days in a hot compost bin, there will be a compost that can be used but expect more to do. Unless extra heat is put into a hot compost bin to keep the heating effect going, the rate of composting will revert to that of a cold rot.

As for the 6 months that it will take for compost to be fully formed in conventional compost bins, this, to, is optimistic. It would be achievable if the contents of the bin were regularly agitated. Adding hydrated white lime will also make a big difference.

You can’t change the process in any compost bin unless you intervene by agitating the rotting material, which will help by introducing air into the mass.

I know this from my own experience with the Rolypig compost tumbler. Here, the contents of the tumbler are regularly disturbed by rolling and there’s the actions of a strong population of worms. A fine, black, crumbly compost can be expected from the Rolypig, at about 16 weeks.

Wormery compost bins produce the finest compost

There are specialist wormery compost bins that can be set up and used indoors. The structure of a wormery compost bin is more refined than that of most other compost bins. They’re made up of layers of container trays that fit together, one on top of the other in tower formation.

The bottom tray is a sump that collects liquid from the process. The liquid is drained out through a tap and the whole assembly is usually raised on legs.

Wormery compost bins are designed to take small amounts of food waste from the kitchen, on a regular basis. It’s no good turning up with a wheelbarrow loaded up with grass clippings, to go in a wormery compost bin.

You start by filling the lowest tray, above the sump-tray, with kitchen waste. The worms can be introduced when the waste has become rotten enough for the worms to digest. Worms can’t digest fresh waste. They’re only interested in anything that has gone mouldy; they eat mould, or organic material that’s starting to become compost.

Another approach could be to place a layer of compost with worms in it, in the tray before adding kitchen waste. When the kitchen waste is moulding or rotting, the worms will venture into it and get to work. It may help if you add some shredded, damp newspaper on top of the worm compost. This will keep the worms moist and they will eat the newspaper if there isn’t enough other organic material.

Using worm compost bins, that are designed to be indoors, is a convenient way of using the power of worms to convert kitchen waste into worm compost but all compost bins can, effectively, become wormery compost bins.

You can add worms to the content of basic plastic compost bins and they will take up residence. In many cases you don’t need to add worms. Compost bins that are open at the base will allow the organic waste to be in direct contact with the ground. If there are, and there probably will be, worms in the soil beneath, they will migrate into the waste and quickly multiply.

Worms actually find their way into the Rolypig compost tumbler. This is due to the tumbler sitting on the ground. To look at it, you would wonder how they get in but they do and they don’t seem to be too bothered by the occasional rolling. The Rolypig can take its place among wormery compost bins.

Other types of rotating compost bins tend to be off-the-ground which prevents worms from finding their way in. For these types of compost bins it will be necessary to add some worms when the compost conditions are right. At some point, most rotating compost bins need to be emptied as they tend to be batch systems. It will help if you leave some worm-laden material in the rotating bin and allow the population to rebuild into the fresh organic material as it arrives.

Rotating compost bins have their limits

This could be described as a more dynamic way of making compost. Rotating compost bins need to be rotated but you don’t need to over do it. Just the occasional roll-over will suffice. Rotating will break up the organic material which will become settled and solidified when left undisturbed.

Compost tumblers are a whole section on their own in the world of compost bins.

The down-side of most rotating compost bins is that when they are full, you have to find somewhere to dispose of any kitchen waste while the most recent addition in the tumbler is allowed to rot enough so that the whole mass is at, or near, a constant and there’s no fresh material lurking in it.

Another way would be to empty the entire contents of the bin into a basic compost bin. Having been rotated, most of the compost from a rotating compost bin will be well on its way to becoming compost, so it should work well when dumped in a static compost bin.

Here, I can explain the advantage of the Rolypig compost tumbler. The Rolypig never needs emptying. When the barrel is becoming full, you can remove some compost from the rear end as the fresh material gradually works its way from the front to the back.

We’re focusing, here, on static compost bins but if you want to know more about rotating compost bins, take a look at ‘are-compost-tumblers-any-good?’ to find out more.


Some examples of static compost bins that are out there.


The Green Johanna

This is one of many among the conical compost bins. It has ventilation ports in the lid. There are also ventilation inlets at the base.

Compost bins

The Green Johanna can be converted into a hot compost bin with the available addition of an outer assembly of covers that provide insulation.

Compost bins


Hotbin composters

This is the Hotbin MK.2 Composter. It’s seen as a solution for small spaces. The thick-walled insulation is designed to hold in the heat that will be generated during the composting process. There is no doubt that containing the heat in this way will speed up the composting process.

Compost bins_ hot

This may be an advantage for those who want to accelerate the process of converting organic waste and, thereby, reduce the need for extra capacity that requires space that you don’t have.

There’s a temperature gauge on the lid that allows you to monitor the heat being generated and contained within the vessel. There’s a sump-tank at the lowest point for collecting valuable liquids. Basic compost bins, generally, allow these high-nutrient liquids to drain into the ground.

The down side to hot compost bins can be that they tend to generate a smell. This particular system contains a carbon filter. Carbon used in this way will reduce smells to a bearable level.


The Blackwall compost converter

Compost bins_plastic

Made from mainly recycled plastic, hence the black colouring. Most black plastic products tend to be UV stabilized which helps to protect them from the effects of sunlight. This is a simple in-at-the-top, out-at-the-bottom compost bin. Everything about this compost bin is simple, from the solid and firm-fitting lid to the easy access hatch at the base for extracting finished compost. The conical shape will ensure that the composting material within, will drop down.


The Rapid Composter

This one is down as another hot compost bin making use of the heat generated in the composting process. It’s a sizeable vessel that will cater for most, if not all, of the kitchen waste from an average home. It has a snug fitting top which has hinged lids which are easy to open.

Compost bins_rapid

There is a built-in ventilation adjustment in the main lid that can be varied for winter or summer conditions.


The Thermo-king compost bin

Compost bins_thermo

This is down as another of the hot compost bins. It has insulated walls plus a ventilation facility that combines to provide efficient and speedy compost making. The lid consists of two hinged doors which allow for filling from both sides. The unit is self assembly but, by all accounts, it’s easy to put together.


The Eco-Master

Compost bins_eco

This is another variation of all the compost bins out there. Made from recycled plastic it can be tucked away in the garden in a convenient place. The whole bin has ventilation ports and the hinged lid can be secured to prevent it from flipping off in the wind. The compost can be removed through the door at the base.


The Garden Composter

Compost bins_garden

This imaginatively named compost bin is a cheaper option if you’re looking for something that’s bargain-basement among compost bins. It ticks all the boxes as a well built, ventilated compost bin that has a hinged lid for filling and the standard ground-level door for removing finished compost. The profiled panels arrive flat-packed and they can be easily assembled as they interlock with each other.


The Beehive compost bin

Compost bins_beehive

If you aren’t so keen on all the plastic compost bins that are out there but you still want the in-the-top and out-the-bottom method that those compost bins provide, there’s this. Cunningly disguised to look like a beehive, it works just like all the other similar styled compost bins. The whole thing arrives as a stack of wood planks which need to be slotted together to bring you the finished article.


Modular wood compost bin

Compost bins_Modular wood

Being made of wood, these types of compost bins tend to blend in with most garden environments. The modular aspect allows for plenty of capacity which makes it ideal for small amounts of kitchen waste together with larger volumes of lawn clippings and shredded hedge trimmings.

Out of all the compost bins that are out there, this could be described as the most basic although more organised than having an open compost heap that just piles up.

With this system you can have as many compost bins as you need to be able to make use of all the waste that you generate, limited only by the space that you have in your garden area.


The Easy-Load wooden compost bin

Compost bins_Easy load

This is an ideal compost bin for garden waste only. The open, airy scheme allows for the effective rotting of garden waste, for example lawn clippings and shredded hedge trimmings. It isn’t suitable for kitchen waste as this would leave food scraps exposed to predators. These types of wooden compost bins need to be made from wood that’s been treated with wood preservatives to give them a long life. This particular model is pine-wood that’s been pressure-treated. The makers claim that it should last for 15 years.


The Tumbleweed Worm Cafe

Compost bins_worm cafe

Using worms for making compost leads us to the more refined types of compost bins. Worm compost bins can only handle small amounts of organic material which means that they can only be used for kitchen waste.

This unit comes complete with everything that you need to set up a wormery. Liquids that are high in nutrients can be drained off from the tap at the base, where the liquid collects. The worms start off in the lower tray above the liquid collection tray, then they migrate up into the trays above through the worm-permeable tray-floors.


The Tumbleweed Can-o-worms

Compost bins_can-o-worms

This works just like the Worm Cafe. It’s a smaller unit with just two trays with a sump tray and tap for draining off the inevitable liquid.


How do you decide on which compost bin to use?

Any of the compost bins that we’ve looked at here will make compost from organic material. All you need is a vessel that will contain kitchen or garden waste long enough for it to turn into compost. So, making a choice is down to how much you are prepared to spend together with the appearance of any compost bin that you may like the look of. After that it’s a matter of how much compost bin capacity that you may need for the amount of organic waste that you generate.

You will end up with the amount of compost that can be generated from the sum-total of the waste that you have. If you are producing a lot of organic waste you may find that one compost bin won’t be enough. Don’t be tempted to try and rush the process and take compost from a compost bin before it’s ready.

Installing more compost bins will give you more capacity that will allow for the composting process to be complete. This will give you a compost quality that will provide more value in the finished product.


Is it worth having a compost bin?

Is a compost bin worth it? If you compare the throwing of organic waste out to go to landfill with holding onto it in a compost bin for, maybe, twelve months, compost bins are worth having. It’s easy to see how a lot of people prefer to go the landfill route for short-term convenience but anyone with the smallest of gardens, and some patients, will benefit from storing kitchen and garden waste in one or more of the many types of compost bins that are out there.

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