Need to know
- More than a third of household waste is made up of food, which creates methane when it decomposes
- For a successful compost system, you'll need a good balance of 'green' and 'brown' materials
- There's so much you can compost, from tea bags and newspaper to eggshells and vacuum cleaner dust
When we throw things in the bin, we don't often think about where they'll end up. All we know is that the garbage trucks take them away – but where is this 'away'?
More than one-third of household waste is made up of food. When this makes its way to landfill and starts to decompose, it produces methane – a greenhouse gas that contributes to global warming.
Reducing the amount of food we waste is a big undertaking, but one simple way you can reduce your environmental impact is to divert food waste from landfill by composting. Composting breaks down the food in a way that doesn't produce methane, and gives you the benefit of beautiful, rich compost that you can use in your garden – it's a win-win situation!
You might even find that setting up a composting system opens your eyes to the amount of food that gets wasted, and makes you rethink your next shopping list and the way you cook.
So you've got your food waste – now you just chuck it in a compost bin, right?
Well, not quite. Composting is a great way to dispose of food waste, but if you just chuck a bunch of food scraps into a bin, you're going to end up with a stinky, slimy mess (and quite possibly an infestation of cockroaches and rats).
Generally, you'll need to keep the ratio of green to brown at about 1:1 by weight
One of the keys to successful compost is a good balance of carbon and nitrogen. Sounds complicated, right? It's honestly simpler than you might think.
Greens and browns
In the composting world, this ratio is referred to as a good balance of 'green' (nitrogen) to 'brown' (carbon).
Green materials are things that contain nitrogen, such as:
- lawn clippings
- fruit and vegetable scraps
- green leaves
- green weeds.
Brown materials are things that contain carbon, such as:
- shredded paper (not glossy paper)
- dried leaves
Generally, you'll need to keep the ratio of green to brown at about 1:1 by weight, which is about 1:7 green to brown by volume.
Other essential elements
Composting isn't as simple as throwing kitchen and garden waste into a compost bin and hoping for the best. Aside from ensuring a good balance of green and brown materials, you'll also need a few other elements.
Water – but not too much
A dry compost bin or pile won't break down – but adding water can help. Regularly water your compost whenever you add to it.
But it's important to get the balance right. Too much water will leave you with a stinky, soggy mess. "Moist but not wet" is a good rule of thumb. One way to test is to grab a handful and squeeze it – about one drop of liquid should come out.
Composting is an aerobic process, which means that it needs air to work. A compost bin that isn't aerated can smell really bad.
To introduce air, turn the compost with a garden fork or composting tool, or put garden stakes or pipes through the heap to allow the air in.
One of the keys to successful compost is a good balance of carbon and nitrogen
Things like twigs, leaves and shredded paper introduce air pockets into the compost, which will help aerate the mix. It's especially important to add these to the bottom of the compost when you're first starting out to allow for air flow.
If you're just starting out on your composting journey, you'll need to add a bit of fresh soil or compost to the mix to get things started. Soil and compost already contain microbes, so adding them to your compost bin will help get the composting process started.
Things you didn't know you could compost
So now you understand the basics, let's take a look at some of the weird and wonderful things you can compost at home.
It's important to note that a home compost system is quite different to an industrial composting system. An industrial system can handle all kinds of things that you wouldn't typically put in a home compost system, such as meat, bones and dairy products. (Seasoned composters may be able to tackle these ingredients, but it's not recommended for those new to composting.)
Here are some products you might not have considered composting.
You can compost any kind of hair – human and animal alike.
You can add hair from all members of your household – human and animal alike! So once you've finished brushing your pets, trimming the kids' hair or cleaning the humans' hair brushes, pop the hair into the compost bin.
Beer and wine
It's tempting to take the zero-waste principle seriously when it comes to alcohol, but if you do happen to find yourself with beer or wine left over, you can pour it into your compost bin. Apparently the yeast in these beverages can give your compost a nice boost.
And if you're a keen homebrewer, the spent grains can also be composted. But this isn't a task for the novice composter – if you're not careful, you could end up with a slimy, smelly compost bin. You'll need to add plenty of 'browns' and aerate well.
Don't worry – we're not suggesting you empty the cat's litter box into the compost!
CHOICE staffer Andrea shared with us the unusual way she uses kitty litter: "We use newspaper-based kitty litter in the bottom of our parrot's cage," she says.
"When I clean it out the whole lot goes into our compost bin. Parrots drop a lot of food so it ends up being equal parts kitty litter, parrot pellet crumbs, vegie fragments and, er, guano."
You can also compost straw bedding from other pets, such as rabbits, hamsters and the like.
Don't bin your coffee grounds – your compost loves them.
As we saw in the example above, some pet droppings are suitable for composting. Manure from chooks, cows, sheep, rabbits, guinea pigs and the like is all perfect for composting.
You can compost cat and dog poo, but it's best to use a dedicated pet compost system – cat and dog faeces have parasites and pathogens that can make you sick. A regular home compost probably won't kill these nasties.
Coffee grounds, coffee filters and tea bags
Yes, you can definitely caffeinate your compost! Just make sure you're using tea bags and coffee filters that don't contain plastic – and ideally look for tea bags that don't have a staple.
Regularly cleaning the fluff out of your clothes dryer is good practice, but what should you do with it once you've pulled it out? Compost it!
Vacuum cleaner dust
Whether you go bagged or bagless, the dust, hair and unidentifiable bits that get sucked up from the floor are generally great for your compost bin, as is the dust from sweeping the floor.
While you can compost dryer lint and dust collected from your vacuum cleaner, you might not want to if the material collected is synthetic
CHOICE TV expert Scott is cautious about adding dryer lint and vacuum cleaner dust to his compost, however.
"Other people have suggested that we empty the vacuum cleaner bag into the compost, but given that it must contain a fairly large quantity of microplastic from synthetic clothing, carpet, etc, I've never thought that that was a good idea," he says.
Sugar cane mulch
As part of your 'brown' component, sugar cane mulch is a great choice. CHOICE staffer Kathleen uses it for a specific purpose: "I usually add a layer of old sugar cane mulch on top of food scraps to keep the fruit flies at bay," she says.
Yes, you can compost paper towels.
Good old kitchen paper towel is fine to put in your compost (with some caveats, of course) – it's classed as brown waste.
"We compost our regular (recycled) paper towels from the supermarket, either in the garden compost bin or in the composting loo, and they do break down entirely with no apparent ill effects on worms, slaters, etc," says one CHOICE Community member.
Before you throw paper towel in the compost, though, consider what you've used it for. If it's soaked with bacon fat, kerosene, paint or harsh cleaning products, pop it into your regular bin.
Old potting mix
Once your pot plants have been in soil for a while, the soil will become depleted of nutrients and you should re-pot in fresh potting mix to help keep your plants happy.
So what can you do with the spent potting mix? Chuck it in the compost, of course! Once it's broken down, you can use the compost as potting mix again – a lovely way to close the loop.
If you've overdone the 'wet' or 'green' components of your compost (things like food waste), then the nitrogen level will be too high, which will make the mix acidic.
While garden lime and dolomite are commonly-known products to counteract the acidity, ash from a wood fire will also do the job. And it'll save you adding more to your landfill bin!
If you've jumped on board the 'booch' trend, you've probably found yourself with an abundance of scoby (symbiotic culture of bacteria and yeast) babies. If you've given away as many as you can but still have more than you know what to do with, you can pop them into your compost.
Once you've been bitten by the composting bug, you'll never think about food waste in the same way again – and that includes food scraps like egg shells.
You'll be pleased to know that eggshells are very welcome in your compost bin. They can take a while to break down, though, so it's best to crush them before you compost them.
If you want a waste-free way to consume eggs, you can also pop your egg cartons in the compost. Just tear them up a bit so they'll break down faster.
Or you can donate them to someone who has chooks – and hope that they'll return a carton full of eggs by way of thanks!
And the rest
These things are also compostable:
- natural fabrics – cotton, linen, silk, wool, bamboo
- old string/twine made of natural materials
- toilet paper rolls
- old herbs and spices
- dry pasta
- wine corks.
Stock images: Getty, unless otherwise stated.