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Composting In Singapore – How To Turn Food Leftovers Into Fertiliser For Zero Waste 

Guide to composting in Singapore

Compost is organic, rich in nutrients and greatly improves soil moisture – earning it immense popularity amongst gardeners worldwide. However, in Singapore, composting in a space-constrained HDB flat can seem challenging. Concerns over smells, pests and dirt can deter even the most ardent gardeners and eco-warriors.

However, if you currently do plenty of food prep at home, just a little effort can yield bountiful benefits from your composting project. To help you get started, here’s a beginner’s guide to composting in Singapore.

Check out more articles on gardening in Singapore:

What can you compost?

You can compost a wide variety of organic goods like flowers, shoots and peels.
Instead of being condemned to the landfill, vegetable peels and scraps can be composted.
Image credit: @communitycomposting

By composting, you can transform up to 60% of your total waste into useful nutrients for your plants – killing two birds with one stone.

For healthy growth, plants require a balance of carbon for strength and nitrogen for faster growth. As such, your compost bin should comprise equal parts of carbon-rich “browns” and nitrogen-rich “greens”.

Examples of “browns” include:

  • Gardening waste like twigs, dried leaves and branches
  • Cardboard packaging materials like toilet roll tubes and egg cartons
  • Newspapers, waste paper and napkins
  • Eggshells, dryer lint, hair and fur

Examples of “greens” include:

  • Gardening waste like grass, leaves and weeds
  • Vegetable offcuts and fruit peels (avoid citrus & onions due to acid)
  • Loose leaf tea, teabags, coffee grounds*

To prevent pests and unpleasant smells, avoid adding these:

  • Cooked food and oily waste
  • Animal-based food scraps like meat, fish and dairy
  • Animal or human waste 
  • Diseased plant clippings
  • Non-biodegradable/paper-plastic mixes like disposable coffee cups, cardboard food boxes, plastic-coated paper pamphlets

* “Greens” and “browns” are general terms and don’t always reflect the colour of the items.

Getting started with composting

The OXO compost bin is a sleek option for the kitchen counter.
While you can purchase sleek ready-made compost bins, modifying a used container will help reduce plastic waste.
Image credit:

While there are several composting methods to choose from, all of them require a similar set of equipment: a watering can, a gardening fork or trowel, some potting soil, fertiliser and a bucket with a lid. For those who are already maintaining a garden, you’ll likely already have most, if not all of these.

Follow these steps to assemble your compost bin:

  1. You can purchase ready-made compost bins made of high-quality plastic and stainless steel.
  2. Line the bottom of your bin with dry leaves and other “browns” 
  3. Fill the first ¼ of the container with soil
  4. After that, fill the bin with alternate layers of browns and greens.
  5. Top off with soil to deter pests

To speed up the composting process, place the bin in a warm, humid place and cut up the waste materials into smaller pieces. Using a gardening trowel, mix the compost pile once a week to help aerate the mixture to encourage decomposition.

Types of composting

An indoors set up can be clean and minimalist.
Though it can seem gross, composting can be performed indoors without much mess.
Image credit: simply by christine

For considerate residents of HDBs and condominiums, it’s important to ensure that our composting setups are compact and don’t produce unpleasant odours. Aerobic composting, the method we’ve discussed above is the most unobtrusive method when well-aired and regularly mixed.

Nonetheless, vermicomposting and bokashi are modifications to the aerobic method that can speed up compost production and to improve its nutrient content with.

Vermicomposting – faster method that can be done in 2 weeks

composting guide in Singapore - composting with worms indoors
Image credit: Singapore Vermicomposting – Worm Composting

Not for the faint of heart, the key to vermicomposting is a wriggling bundle of worms. Icky as they are, these unsung heroes are incredibly beneficial to soil ecosystems, boosting nutrients manyfold while eliminating harmful parasites. Their tunnelling activities can also increase the speed of the composting process by up to two times.

To turn a standard compost bin into a dream home for our noodly friends, simply superglue fine mesh over the holes to prevent them from terrorising your neighbours. Following the same regimen as aerobic composting, your compost will be ready within 2 weeks. Simply put fresh food scraps on one side to entice the worms away as you harvest the compost on the other side.

Composting worms (from $50/200g) purchased from gardening supply shops can be expensive. Alternatively, you can get spare worms from fellow gardeners on these Facebook groups for little or no cost:

Compost ready in: 2 weeks

Bonus: Vermicomposting produces vermicast – worm poop. Known as “black gold”, these can be worth more than 10x regular compost due to its concentration of nutrients.

Bokashi – for home chefs in small spaces

composting guide in Singapore - bokashi is a Japanese method that can be done indoors
A full setup with bokashi bin, bokashi mix and compost bin (L to R) doesn’t need to take up a lot of space.
Image credit: @longfaceshorthair

Unlike traditional aerobic composting that rules out cooked food, meats and dairy, bokashi uses a microbe-rich mix to break it all down via fermentation. This further cuts down your food waste, and produces useful bokashi tea that can be used to fertilise plants, kill weeds, speed up composting, and even to clean and unclog your drains.

Bokashi is usually practised alongside regular composting, and can be done with a simple, small container in your kitchen. Ready-made options start from around $20, but you can choose to upcycle used containers – just ensure they are airtight and have a spout at its base.

To set up your bokashi bin:

  1. Add food waste to the bin once a week
  2. Atop each 3-4cm layer of scraps, sprinkle bokashi mix.
  3. Press down firmly to squeeze the air out, before sealing the container
  4. Drain the “bokashi tea” every 1-2 days – using it immediately
  5. After about 2 weeks, move the solid waste to your compost bin.

Compost ready to use in: 1-2 months

Composting tips

composting guide in Singapore - you can compost eggs and vegetable peels
Image credit: Gardening Know How

When your compost is ready for use in your plant pots, it will appear dark brown in colour – similar to that of potting soil. Just like soil, compost should smell earthy and not sour or unpleasant. 

To harvest, use a 0.5cm sieve to filter out the large chunks, which can be used as starter compost for your next batch. 

If you encounter any smells or pests while composting, try the following:

  • Add more browns to absorb excess moisture, topping off with a clean layer of soil.
  • Test the moisture content: when squeezed, no water should come out.
  • Churn the compost regularly to allow the bacteria to breathe
  • Poke holes in the compost to aerate the mixture

Composting guide for beginners

Organic waste makes up to 80% of our total refuse. For those of us who do food prep and have a garden at home, composting is a good step toward a #zerowaste lifestyle. 

With tools you already have at home, you can give your fruit peels, vegetable off-cuts and packaging materials a new lease of life – as a nutrient-rich boost for your plant kids.

Check out our other articles to help you be more eco-friendly:

Cover image credit: Gardening Know How, simply by christine