So, you want to compost in your kitchen?
The good news is that there are many different options for doing so!
In fact, I face a daily choice of how to get rid of my kitchen waste – do I put in my compost bin, feed it to my worms or put it in the electric composter I am trialing?
To help you choose, I want to outline some of the options available to you, how to use each one and the pros and cons of each option.
But first, let’s explore why you might want to start kitchen composting in the first place!
The benefits of kitchen waste composting
Depending on the system you use, composting in the kitchen can be simple. In fact, it often produces less smell than simply leaving it in a bin until garbage collection day.
It also carries some major benefits.
First, you get to experience the joy of turning something a waste product into compost.
If you grow plants, making high-quality compost instead of buying it can save you money.
It’s not just about money either. There have been repeated issues of commercial compost being contaminated with herbicides, but you will know exactly what has gone into your own compost.
That compost can then help you grow better plants, improve your soil structure and, if you grow your own food, help you to take part in the circular economy.
Composting waste can also carry benefits for the environment.
When food waste goes to the landfill, it creates methane, which is around 30 times worse for the environment than carbon dioxide.
If you compost food, and do it right, you can cut your methane emissions by up to 84%.
Learn more about the benefits of composting.
6 ways to compost in the kitchen
Do note that composting in the kitchen can refer to collecting waste for composting outside or actually making compost inside.
In this section, we’ll cover both types of composting.
Collection
Kitchen caddy
I now have three kitchen compost caddies – one in my home and two at work! You can either buy one or make your own.
While I’m keen on making things, commercial caddies have one big advantage – a carbon filter that is designed to capture odors. This is not so important in the winter, but does really help in the summer when it gets hot and flies are around.
However, if you are getting rid of your waste daily any bowl will do, or you can use a container with a lid.
Also see: A guide to using kitchen compost bins
A word on ‘compostable’ kitchen liners
Compostable kitchen liners have been a source of controversy recently and with good reason.
While manufacturers claim they are compostable, research has shown they do not always break down in home composting systems.
I can vouch for this.
I have tried putting bags of waste in kitchen compost liners in bokashi bins and compost bins, only to find a mess of semi-decomposed waste still in the bag weeks later.
Kitchen liners don’t break down easily and add additional expense and waste to the composting process.
Freeze
What if you can’t empty your bin regularly?
Maybe the weather is foul, you’re busy or in the middle of a harsh winter?
One option is to freeze the waste.
Simply collect it in a bag and pop it in your freezer until you are ready to compost.
(This assumes that your freezer, unlike ours, isn’t always full of food – including all that garden produce you overproduce in the summer!)
Grinding
Some home composters choose to grind down their kitchen waste before composting it.
This does have some advantages.
Because the material is cut into smaller pieces, the bacteria that helps turn organic kitchen waste into compost can more easily access the nutrients they contain.
However, I personally don’t do this – at least for kitchen waste.
Grinding is a time-consuming material that adds complication to the kitchen composting process. I want it to be easy and quick! What’s more, as long as you compost kitchen waste correctly, it still breaks down fine.
What to do next?
There are many ways to compost your finished waste!
One easy way is to dig a trench or pit, add the food waste and then cover it with a soil.
You can also add it to a compost bin or a compost tumbler to turn it into usable compost.
As it’s such a large topic, do explore the linked guides below.
Home Composting Guide | Composting Methods | Trench Composting | How to Use a Compost Bin
Composting in a container or bucket
One of my favorite experiments to date has been micro-composting.
I took a small container (this was a Bokashi bin, although you could use other containers) and managed to turn some basic waste into compost.
How to do it:
- Take a bin or a bucket with a lid.
- Mixed kitchen waste with a dry, brown material. You can either layer it or mix it together.
A brown material here means any material which is high in carbon. Examples include sawdust, leaves shredded paper or newspaper. You want a minimum of 50% brown material to 50% kitchen waste, but more brown is fine.
Why: i. Kitchen waste is high in nitrogen. You need to balance this out with the high carbon found in brown materials. See our guide to the Carbon Nitrogen ratio for details.
ii. Kitchen waste is also usually high in water. The dry material helps absorbs this water.
Iii. The dry brown material also helps reduce odors.
- Optional: Mix a couple of handfuls of mature compost or soil into your compost bin. Some research suggests this can help add the microorganisms that break down your compost.
- Mix the contents together regularly – every couple of days or so is perfect. This introduces oxygen into the compost, which is essential for the microorganisms which break down compost faster and with minimum smell.
At the same time, monitor moisture levels. The compost should be about as damp as a wrung-out sponge.
If it’s wetter, add more dry material like shredded paper. If its drier, add a little water.
Pros:
This system is fun, and costs little or nothing to do.
Cons:
- Slower than hot composting: The most efficient compost bacteria work at high temperatures. As the temperature is not usually very high, it can take longer than other systems.
- Requires inside space: Ideally, you would add material over a few days. However, this would require several bins. You can use it as a continuous composter, but at some point you will need to put it aside and let it mature before use.
Alternative system: Compost bucket with holes
Note that many guides advise drilling holes in the side and bottom of the bucket.
The big advantage here is it helps the compost stay oxygenated, and you won’t have to mix it as often.
However, it also means pests can get into your bin. You also need to place a tray under the bin in order to catch the leachate.
Worm bins (vermicomposting)
I think worms are a great option for composting inside.
(Note, technically you are making worm castings rather than compost, but both are good for your plants and the soil.)
If managed correctly, the system doesn’t attract pests or smells. While a worm bin is not free if bought, it’s substantially cheaper than an electronic bin, and you can also make one very easily for around $20.00 (here’s how).
How to do it
There have been whole books written about vermicomposting, so don’t expect a full explanation here!
- Add bedding to your worm bin. There are numerous options, and these include sawdust, shredded paper, shredded cardboard, new or old compost and coir. I like to include a mixture of different bedding materials, as they all come with their pros and cons.
- Ensure your bedding material is damp – just like with regular composting, the material should feel like a damp sponge.
- Add your worms. Make holes in the bedding material, place your worms in it, and then cover it over again.
- Cover with a layer of damp newspaper.
- Wait a few days before adding food. I like to add just a little bit after a few days and monitor it to see when the worms start consuming it.
- Build up the food over time. Collect any worm leachate, and dilute it down to use a fertilizer.
Eventually, you will be able to collect and use the worm castings with your plants. As there are several options to separate worms and worm castings, that will be the topic of a future article!
Pros
The quantity they can handle: Worms can handle a surprising amount of food waste – around half to a pound of kitchen waste per day.
Cons
Extra care needed: Unlike other systems mentioned here, this does involve looking after live creatures which need feeding and monitoring.
Some people dislike worms: Now, I love worms, but I think I’m the only one in my family. That’s why my own worm bin is in the woodshed! So, even if you don’t like worms, you may find opposition from your family.
Also see: How to make a simple worm bin
Bokashi bins
I was very excited when I acquired my first Bokashi bins from my sister. However, just like her, my enthusiasm ran out of speed.
Still, they do have specific uses, so let’s cover them briefly – there’s also full linked guide below if you want more detail.
How to use:
- Add a thin layer of bokashi bran to the bottom of the Bokashi bin.
- Add 3-4 centimeters of waste food, ideally broken up into smaller pieces.
- Repeat the layering process until you have used up all your waste food.
- Press the mixture down to expel the air.
- Place the lid on top.
- Use the spigot at the bottom to remove the liquid.
- Either dig into your garden or add to a compost bin when finished.
Pros:
Material handled: Bokashi bins can handle a wide variety of material which you might want to otherwise compost. This includes bones, and some systems are even designed to handle pest waste.
Cons:
Ongoing expense: To use them, you do need to buy Bokashi bran, which adds additional expense. You can make it yourself, but this is a time-consuming and fiddly process.
Don’t make actual compost: Bokashi bins make a kind of pre-compost, which can then be added to a compost bin or dug into the soil.
In fact, I wasn’t very impressed when after all the fiddling (and buying the bran) all I got was what looked like some pickled, stewed vegetables. Sure, it should help the soil, but it’s not as good as actual compost.
Want to learn more? See our full guide to Bokashi Bins.
Kitchen composting machines
Yes, there is such a thing as a kitchen composting machine, although more typically these are known as electric composters.
These are powered indoor compost bins that process kitchen waste.
Process, not compost, you ask?
That depends on the bin. Some bins simply grind and dehydrate the food. While convenient, that’s not compost.
Other bins, such as the Reencle, use heat, stirring, oxygen and microorganisms to replicate the system found in a hot composting bin.
How to use?
The exact process will depend on the bin you are using. However, there are a couple of things to bear in mind.
- If you are using a bacterial electric composting bin, research has found that you need to add high-carbon materials as well as high-nitrogen materials. You can add pasta and bread, or simply sawdust.
- If your system does make compost, this needs to be left to mature before use – and research tells us that this needs to be more than a month!
Pros
Convenience: Once set up, these systems are the easiest ones to use.
Aesthetics: These are easily the most attractive solution to use in your kitchen.
Cons
Expense: A typical electric composter will cost hundreds of dollars to buy. For the same money, you could buy more compost than the composter will make.
Environmental benefits are not clear: Electric composters use electricity, and are made of plastic and metal. That makes it harder to calculate if the benefits of using the device outweigh the carbon footprint of the actual device. (Do note that I have found you don’t need to have these switched on all the time for them to work.)
Learn more: Reencle Home Composter Review
Cardboard box composting
The Japanese have an interesting way of composting in the kitchen. I’ll give it a brief mention here (brief, as this is the only method mentioned here I haven’t yet tried).
How to do it:
- Take a corrugated cardboard box and make holes for ventilation.
- Add coco peat and rice husk charcoal, which absorb any liquid or odours.
- Add your food waste.
- Cover with an insect-proof screen.
What can and can’t be composted in the kitchen
Typically, almost anything that has recently been alive can be composted.
However, more challenging items should only be composted in a hot composting system or in a bokashi bin.
That’s especially the case in a kitchen composting system, where you are unlikely to achieve hot composting conditions.
In general, you should avoid composting fish, bones and dairy products.
Of course, that also depends on the system you are using.
A bokashi bin can handle bones and meat, as can some electric composters.
For more information, see:
Compost Materials (What You Can and Can’t Compost) | The Truth About ‘Non-Compostable’ Items
How to use your kitchen compost
First, with all compost, it’s a good idea to let your compost mature before use.
This will allow the compost to stabilize. The salts in the compost will reduce, and some nutrients will turn from a form that will easily leach out of the compost (soluble) into a form where it will carry longer-term benefits for the soil (insoluble).
This is important, as fresh compost can burn plants.
You then have lots of options on how to use it! These include:
- Use it on or in your soil. The compost will provide some nutrients to plants, but it will also feed the microorganisms which have a mutually beneficial relationship with your plants.
- Sieve it and use it as seed compost. You may want to dilute it with another material such as sand first, though!
- Use it with pot plants.
That’s just scratching the surface – for more detail, see our in-depth guide on How to Use Compost
Wrapping up
If that all seems a lot, remember we’ve touched on several different methods here!
The key is to simply select the one that suits you the best, and give it a go.
Remember, composting doesn’t have to be complicated, it can provide benefits to the environment and your plants and can help save you money too!
So why not give it a go?
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External resources
Composting For a New Generation: This is my favorite book on composting (see review here). It’s full of clear, actionable advice and composting projects illustrated with easy-to-follow photos.
FAQs
How can I manage the smell from kitchen composting?
If you do things right, there should be no major unpleasant smells. However, you can always add a layer of sawdust or mature compost at the top of the bin which will help absorb smells. You can also add ash or biochar. If using a caddy, choose one with a carbon filter.
How long does it take for kitchen waste to turn into compost?
It usually takes several months for kitchen waste to fully turn into compost, although this does depend on the system you use and conditions like moisture and temperature.
How do I know when my compost is ready to use?
The organic material should have turned into a brown crumbly material. To test whether it is ready to use, try germinating some fast-growing seeds like radish in it. If they grow well, your compost is likely ready!
Can I compost cooked food scraps?
This depends on the system you are using. For example, if you are composting in a bucket, I would avoid it. However, it is fine to add cooked scraps to a bokashi bin.
Can citrus peels be composted?
Some sources advise against composting citrus peels, due to the extra acidity they create in the compost. However, if you are composting moderate amounts of citrus peels in a balanced composting environment, the quantity is not usually enough to create a problem.