Horticulture Magazine

How To Start And Use A Compost Bin At Home

peeking into a black compost bin with eggshells and vegetable waste on the surface

You don’t really ‘use’ a compost bin you may think; all you do is throw clippings, vegetable refuse, and such in it, and that’s that…except that it isn’t.

In order to make high-quality compost without running into trouble, you really have to ‘use’ your compost bin, and use it effectively.

This means taking several measures.

Composting Methods

household waste being poured into a compost bin

To begin with, two methods can be used to make compost: the Batch Method and the As-You-Go Method. Here’s how they work:

The Batch Method is a two-step method such that first you prepare the pile by putting in the materials and contents that are to be composted, and then you ‘cook’ the whole thing as a batch.

In contrast, As-You-Go is an iterative method in which adding composting materials and the ‘cooking’ occur without discrete steps as a single ongoing process. Compost bins are ideally suited to As-You-Go Style composting while compost tumblers are better for the Batch Method.

As this is an instructional article about making compost in bins, our primary focus shall be on the As-You-Go Method.

The Carbon:Nitrogen Ratio

an illustration of browns and greens that can be placed in a compost bin

Effective usage of your compost bin requires that you get the Carbon:Nitrogen – C:N – Ratio right.

For a compost bin the ideal C:N ratio is from 25:1 to 35:1. [source]

The C:N ratio is colloquially but incorrectly also called the ‘Brown-Green Mix.’

Be mindful that C:N and Brown-Green do not have a direct correspondence:

  • ‘Green’ compost content has a fairly narrow range of C:N ratios hovering around 30:1
  • ‘Brown’ content’s C:N ratio and, therefore, carbon content, varies widely. It ranges from 40:1 to 600:1!

Also, where composting is concerned, ‘Green’ content includes that which is green in colour; however, material like tea leaves, coffee grounds, and manure are considered ‘Greens’ because of their C:N ratios.

Two Simple Rules

an illustration of the 30/70 greens and browns split for composting

You can hit the desired C:N ratio by following two simple rules:

  1. Strive for a Green/Brown materials 70/30 mix: that is just over two parts Green to every one Brown.
  2. Be careful with woody and wood-derived materials; use these in very low quantities because they have an extremely high proportion of Carbon to Nitrogen.

Turning and Aeration

using a fork to turn compost

Turning and Aeration are crucial to making high-quality compost.

The reason to turn and aerate a compost pile is that if it just sits then the material near the top will decompose at a faster rate while the material that is at the bottom, and which is being compressed by the pile’s weight, will decompose at a slower rate.

Organic materials need air to decompose but materials that are in the middle of the pile or compressed at the bottom would be starved of air.

Turning the compost pile means that there is no bottom layer and no top layer, and this agitation ‘fluffs up’ compressed materials and opens up air channels in them.

Vigorous turning will also bring another benefit; it will tear and break up scraps and pieces.

cross section of a compost bin
Cross-section of a compost bin that has not been turned

Use A Handheld Aerator

a handheld tool being used to aerate compost

You will need to turn and mix up, and thus aerate, your compost pile by using a handheld aerator.

Try to choose one that is right for you and also for your compost bin.

If you want to be frugal and go low-tech, do as your grandpa did and use a pitchfork.

Aerate the pile twice or thrice per week.

Also, do so when you add a fair quantity of material to your As-You-Go pile in the bin.

You can insert your aerator through the built-in holes at the top and/or the sides of your bin.

However, you probably will be more comfortable and will be able to do a better job of turning and mixing the compost if you open the lid and use the aerator through this (much) larger opening.

Wetness

a hose pouring water on a compost pile

The moisture content of the compost pile is another key to effective decomposition.

The pile should remain damp and should never be allowed to dry out because if it does, ‘cooking’ will slow down and the pile will also decompose (more) unevenly.

If, when turning the pile, you observe that it is dry, conservatively water it all over as you turn it such that it is well moistened and damp but not wet.

What Can You Put In A Compost Bin?

metal bucket full of organic waste
A bucket to collect and transport organic waste can be useful

The short answer: anything organic, because it will decompose.

The best things to put in a bin are old compost, garden soil, garden clippings and cuttings, vegetable and fruit waste, grass clippings, fresh leaves, dry leaves, mulch, kelp and other seaweed, hay, and straw.

Try to chop up or dice big cuttings otherwise they will not decompose as rapidly as you would like.

Household Waste

illustration of the materials that can and cannot be composted

In addition, you can put carefully-selected leftover food scraps, twigs, newspapers, rough (not coated or shiny) cardboard, manure, sawdust, wood chips, tea leaves, coffee grounds, old cotton cloth, eggshells, and peat moss.

Do not add rice or grains, cooked or uncooked, or meat or dairy products.

Rice and grains will bring rodents to your compost bin while meat and dairy will attract flies and may well putrefy instead of aerobically decomposing.

Newspapers and cotton cloth should be torn into small pieces and soaked or wetted before being added to the bin to promote decomposition.

All wood-based and wood-derived materials have a very high C:N ratio – 400:1 and higher – so be conservative when including such materials.

Err on the side of too little of these than too much, otherwise the compost pile will remain dry, won’t heat up, and will decompose very slowly and very unevenly.

Layering Materials

layering household waste on a compost pile

How you arrange or layer these materials initially is of some importance.

Put a layer of commercial ‘starting soil’ aka compost starter, plain compost, or even plain garden soil at the bottom, and put a layer of one of these same components right at the top.

Of course, when you turn and churn the pile after a few days everything will get mixed but ‘layering’ is the way to start off on the right foot.

If you anticipate that you may not turn the compost pile for more than three days, put a layer of starting soil (or substitute) on the top.

Weeds

weeds piled up next to a composter

Weeds are organic plant-based material but if you are new to composting or simply don’t have time for fussing, do not put any weeds in your compost bin.

Weeds enjoy warm and rich composting materials so much that they will take root and grow in your compost pile!

On top of that, if weeds go to seed as your compost ‘cooks,’ you could end up with weed seeds in your compost – which means that your nice new compost would sprout weeds.

The way to make sure that weeds do not germinate and turn into compost is to ‘pre-bake’ them, or to use the Batch Composting method, turn the pile very frequently, and even monitor the temperature at its centre to be sure it does not drop below 65°C.

And for all that, you should not put pernicious weeds, like Bishop’s weed and crabgrass, in your compost pile at all.

Manure

manure in a wheelbarrow, placed next to a vegetable patch

If you add manure to your compost bin, do not include horse manure at all.

Other types of manure may be added but these should not be fresh but old or ‘aged.’ Fresh manure is simply too hot to add to a compost pile.

What to put in a compost bin when starting

old fruit, eggshells, vegetables placed on top of a compost heap

A very good mix to start off a compost bin would comprise of vegetable and fruit refuse, grass clippings, tea leaves and coffee grounds, chopped or torn-up dried leaves, wetted old cotton cloth or some shredded and wetted newspapers – not to forget some commercial ‘starting soil’ aka compost starter, regular compost, or even plain garden soil.

While these limited materials in the right proportions make for a very good Brown-Green mix, they are also very readily accessible.

How to keep your compost bin from smelling

waste spilling out of a compost bin

To keep your compost bin from smelling, first, you need to make sure that the pile will decompose evenly and aerobically, and not unevenly or anaerobically.

To achieve this rather important end, the pile needs to have air circulating within it – even right at the very bottom.

Turning and aerating the pile with an aerator will ensure that there is no ‘bottom layer’ as such because the pile gets turned and churned.

It also ensures that all the bits and pieces get separated which means that air channels open up throughout the pile, increasing airflow.

Second, your pile’s Carbon:Nitrogen balance should not tip over too far towards Nitrogen which can and does happen when too much ‘Green’ and too little ‘Brown’ is added. [source]

Be sure that you keep adding a sufficient amount of ‘Browns’ to balance whatever ‘Greens’ you add.

Finally, some materials are smelly to begin with and are also more likely to putrefy and emit foul odours.

These include meat and dairy products and, yes, manures.

You can exclude such materials without any negative impacts on your compost pile.

Pests

Grubs

rose chafer larvae in a compost pile
Rose chafer larvae in a compost pile – yuk!

First, think it over. There are grubs, and then there are grubs.

Many of them, like earthworms and microbes, are actually beneficial to your compost pile without ever being harmful, even after you use the compost in your garden.

Grubs burrow and tunnel through the pile thereby creating air-channels and doing some of the aeration for you; futhermore, like microbes, many grubs feed on organic materials and decompose them.

Now if you have identified pernicious grubs or that may harm your garden, if your pile is simply infested with grubs, or if it has maggots, then you would need to get rid of them.

Nematodes

Buy or order a supply of Beneficial Nematodes, these are available at garden centres and online sellers.

Follow the instructions and introduce the Nematodes into your compost pile.

Goodbye, grubs.

Neem Oil

If your compost pile is on the small side, you could get a bottle of Neem Oil.

It works as a natural pesticide against grubs (and even garden pests).

Dilute the oil to a strength somewhat greater than what is outlined in the instructions, be sure you have created a good suspension, and spray it into the pile as you turn it.

Birds

You could also try to put a bird feeder very close to your compost pile.

The birds that you attract may go on to feed on the grubs in your pile!

Flies

close up of a fly sat on a black compost bin

To begin with, keep the lid tightly closed.

If your compost bin is a jerry-rigged affair and has no lid then cut out the appropriate size of heavy-duty but fine wire mesh such that you can bend the mesh over the rim of the bin and secure it.

You will also need to cover the side air vents with a mesh netting.

Flies are drawn to food waste, therefore push all food waste (and whatever else may attract flies) to the middle of the bin.

Do not leave such materials at or near the surface.

If you are developing a serious problem with flies, eliminate food waste altogether.

Additionally, after turning the pile put a thin layer of grass clippings on top; this will not draw any flies.

Rat-Proofing

rats inside a composting bin

As the first step, you can ‘rat proof’ your bin by simple dint of using an all-solid bin made of hard materials and always keep the lid tightly closed such that it cannot be dislodged by these clever and persistent rodents.

Cover up any side vents with rat-proof wire netting.

You can ‘rat proof’ your bin’s interior by not adding any materials that would attract rats.

These include leftover food scraps, meat, dairy, and eggshells – and you can live without these in your compost pile so nothing’s lost.

To play it safe, keep the pile very much on the damp side. Rats will take to a dry’ish compost pile but not to a damp one.

Put the bin on a concrete slab in an open, unsheltered area that does not provide any cover.

Install an 11-watt daylight LED near the bin and keep it on from evening to dawn.

You may also consider doing what our ancestors used to do in mediaeval times: keep a good ‘mouser.’

If you take all these measures you should never have any rats in or near your compost bin.

FAQ’s

Should I put earthworms in my compost bin?
earthworms visible in compost pile

You don’t need to but you certainly may.

If you want to put worms in your compost bin, put in red wriggles.

They are perfectly adapted to the conditions of a compost bin and can be seen as “Mother Nature’s Composter”.

As for earthworms, they are more sensitive to the highly variable conditions of a compost bin.

Actually, if your compost pile offers conditions favourable to earthworms then they will make their way to it themselves but you can give it a shot and dump in some earthworms and see what happens.

If they thrive in your compost bin you’ll have lucked out twice over. 

  1. First, earthworms, like grubs, burrow and tunnel through the compost pile. In so doing they too create air channels inside the compost pile, aerating it. [source]
  2. Second, earthworms consume much of the materials in the pile. What they excrete, called ‘castings,’ is rich in micronutrients and nitrogen, and is one of the bases for high-quality compost. [source]

Composting with the aid of worms is known as ‘vermicomposting.’

illustration explaining the layers of a vermicomposting bin
Do compost bins smell?

Compost bins may smell a wee bit, yes.

Depending on what has gone into a Batch Style compost heap, it can smell a little initially.

And depending on what you may add to an As-You-Go Style compost pile it too may smell a bit.

hen again, just as often a well-maintained compost bin will give off a warm, musty, earthy odour that may even be quite pleasant.

food sat on top of compost

Well-tumbled compost in properly-used and aerated bins should not smell particularly bad at all.

But sometimes compost bins do smell bad, and when this happens it signifies that something has gone wrong.

One reason behind it could be that the compost pile, instead of decomposing aerobically, is putrefying – decomposing anaerobically, i.e. without oxygen which points to inadequate aeration.

Another reason behind it, especially if the bad smell is like ammonia, is a seriously out-of-whack Carbon:Nitrogen ratio skewed in favour of Nitrogen.

And if you’ve been naughty and went and threw leftover meat or dairy into your bin, well…

How big a compost bin do I need?
a huge compost bin separated into three segments

To a large extent, this depends on both your gardening and compost needs and on the amount of composting materials you will generate and source.

Commercially-available compost bins meant for individual and household use range from a volume of a measly 150 litres up to a huge 1,600 litres – a factor of over ten!

Try to estimate the volume of compost you want to make and buy a bin of the appropriate size.

If you estimate your volume in litres, it is easy to calculate the overall dimensions of the compost bin you need: simply multiply the litre value by 1,000 to arrive at the bin’s size in cubic centimetres.

Can you put newspaper in a compost bin?
various vegetables, fruits, eggshells and newspaper cuttings in a grey plastic compost bin

Yes, but in its correct proportion which, in a compost bin, would be in a moderate volume.

They are a ‘Brown’ source and add the necessary carbon to a compost pile but at the same time, the C:N ratio of newspapers at about 200:1 is significantly, though not overwhelmingly, oriented toward Carbon.

Also, it is best if newspapers are shredded or at least torn up, and soaked or at least wetted, before being put in the bin.

Otherwise, they will take very long to decompose and may even cool down your compost pile.

Can you put old compost in a compost bin?
a garden fork lifting compost

Yes. Compost is one of the best ‘ingredients’ for a compost bin as long as it is not poor-quality.

Not only that, but good-quality old compost is an excellent ’starter,’ be it when starting an As-You-Go pile or preparing a compost tumbler’s Batch.

Finally, if you ever discover that your compost bin’s C:N ratio has tipped over a little too much in favour of either Carbon or Nitrogen, apart from taking other necessary measures, one of the best ways to get things back on track is to add high-quality old compost.

Should you place it in the sun or shade?
black compost bin next to a hedge and fencing

As a general rule, in the sun, but in practice it depends on a couple of factors.

Direct sun and the resultant heat speed up the process of decomposition, and they aid in ‘cooking’ the pile so this major benefit is a compelling reason for siting your bin in the sun.

Except that direct sun and high heat also dry a compost pile – it needs to be damp.

Thus, direct sun and high heat also eventually slow down the process of decomposing by drying out the pile!

You can put your bin in the sun and easily work around this drawback by monitoring the pile for dryness and watering it regularly.

On the other hand, if you are specifically doing vermicomposting, then you will need to avoid hot sun and keep your compost bin in mostly shade because typically worms cannot tolerate high heat.

Like many things in life, opt for a happy medium and try to locate your compost bin where it gets a good amount of sun in the morning and late afternoon but not the hot midday sun.

For more composting guidance see also: how to make a home compost heap.

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