Compact Aerobic Composting Guide for Small Spaces and Balconies in Singapore

Last updated on 2 June 2024

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“Why so troublesome to compost? Why not just add fertiliser?!’

Living in a big metropolis like Singapore, it’s too easy to become dependent on a quick fix of commercial fertiliser for your veggies and herbs without realising the long term negative effects.

Just a spoonful of fertiliser, to help my plants grow.
(Source: Tenor)

The downside of relying only on fertilisers

While fertilisers, including organic ones, can boost plant growth, they come with disadvantages. They tend to be poor or devoid of beneficial microbes that are important for the long-term health (and taste!) of your plants.

Fertiliser overuse could lead to salt built-up. The excess salt harms beneficial microorganisms, pollute ground water and cause plants to struggle to draw water.

Overly concentrated synthetic fertilisers could also burn your plants’ roots.

Yup, that’s what you are doing to your plants (and your health when you eat too much ban mian).
(Source: Tenor)

Why Composting is Beneficial?

A fundamental aspect of sustainable gardening, composting is the process of breaking down organic matter into nutrient-rich fertiliser (“compost”).

By diverting organic waste from landfills and transforming it into valuable compost, you reduce your environmental impact while simultaneously enriching your soil.

Compost provides a rich source of nutrients, including nitrogen, phosphorus, and potassium which are essential for plant growth and health.

Now go forth and show bulbasaur who’s boss! (Source: Tenor)

Additionally, compost helps retain moisture in the soil, reducing the need for frequent watering.

“But I don’t have money to buy a house with a big garden in Singapore. How to compost?”

Aerobic composting for smaller spaces

One way to overcome the lack of space is through aerobic composting, a natural process that decomposes organic waste using air-breathing microorganisms.

This method involves regularly turning your compost to ensure adequate oxygen supply, accelerating the breakdown of materials and reduces odour.

By utilising small containers, such as buckets or plastic bins, you can easily implement aerobic composting on your balcony or in a small corner of your coridoor.

Why it’s better with oxygen?

Aerobic composting is considered one of the most natural and environmentally friendly forms of composting.

Benefits include faster decomposition, the production of nutrient-rich compost for gardens, and a significant reduction in greenhouse gases compared to anaerobic methods.

Other composting methods include anaerobic composting, which occurs without oxygen and takes longer, and vermicomposting, which uses worms to break down waste. Each method has its unique advantages and suitability depending on the composting goals and available resources.

It’s much harder than you think to find worm suppliers in Singapore. (Source: Tenor)

For aerobic composting (i.e. in the presence of oxygen), this method is cost-effective as a large and basic container with some aeration holes would suffice to compost readily available materials like kitchen scraps and yard waste.

No need for airtight equipment, expensive bacteria accelerators or worms buying!

Key components to build your compost: browns and greens

Browns (Carbon-Rich Materials):

Uncoloured, unprinted paper
Cardboard
Dead leaves
Twigs
Egg cartons
Non-glossy cupboard pieces

Greens (Nitrogen-Rich Materials):

Vegetable and fruit scraps
Eggshells
Tea and coffee grounds

Avoid Composting:

Meat and bones (attract pests)
Oil and fat (disrupt moisture balance)
Animal waste (potential bacteria hazard)
Cooked food

As much as possible, choose organic and disease-free compost ingredients. You’re gonna eat those plants at some point!

You are what you eat. I am… BAK CHOR MEE. (Source: Tenor)

Choosing the right container

A large container, preferably at least six litres and as tall as your space allows. The container should allow air circulation, essential for aerobic composting. Some commercial ones come with an active carbon filter to remove any smells.

Drill a few small holes in the lid for ventilation if it’s an airtight one.

Setting up your composting process

Layering: Alternate layers of brown and green materials. Aim for a 50/50 ratio by weight, but lean towards more browns for better results.
Size Matters: Chop or shred your compost materials into small pieces to hasten decomposition.
Microbial Boost: Add a few cups of good soil or existing compost to introduce beneficial microorganisms.
Moisture Control: Add water to slightly moisten the mix, avoiding excess that leads to waterlogging.
Aeration: Stir the compost every two weeks to provide oxygen and accelerate the process.
Location: Place your compost bin in a shady, open area. Preferable on the balcony or your coridoor. Try not to leave it indoors as it encourages fungi.

Then sit back and let nature do it’s magic (Source: Tenor)

When is Your Compost Ready?

In Singapore’s climate, compost is typically ready in about 3 months. It’s done when it’s dark, crumbly, and has an earthy smell, with no visible food pieces.

Using Your Compost

Compost is a fantastic soil amendment. Mix it into your potting soil or use it as mulching (i.e. spread it on the soil surface around the plants).

The surface compost minimises moisture losses and weed population, while enhancing nutrient content and crop yield.

Additional Tips for Successful Composting

1. Achieving the Right Balance of Browns and Greens:

More Browns: Adding extra browns helps absorb excess moisture, which is crucial in Singapore’s humid climate. This prevents your compost from becoming too wet and smelly. Browns like dry leaves, shredded paper, or cardboard also add carbon, essential for compost microorganisms. You can also add a layer of soil or leave the compost bin lid ajar on a hot day for a couple of hours to manage humidity.
More Greens: If your compost is too dry or decomposing slowly, increase the greens. Kitchen scraps, grass clippings, and coffee grounds add nitrogen, speeding up the composting process and generating necessary heat.
Save up for enough before composting – kick start your composting journey with a large enough batch of greens (freeze those scraps in an air-tight) and browns to fill up most of the container, then leave it alone! If you keep adding compost material in small amounts each time, your bin will have different compost stages and this lengthens the process.

2. Proper Aeration and Turning:

Regular turning of your compost is key. This introduces oxygen, crucial for aerobic decomposition, and prevents material from becoming compacted and anaerobic. Use a simple garden fork to turn your compost every two weeks. This also helps distribute moisture and heat evenly, promoting faster decomposition.

Is it me or does the above composting advice also apply to economical rice or “cai png” in Singapore? 🤔 (Source: Tenor)

3. Pest and Odour Management:

Pest Control: Ensure your compost bin is well-sealed to keep pests out. A tight-fitting lid and a location away from direct access points for pests are essential. Avoid adding materials like meat, dairy, or oily foods, which are more likely to attract rodents and insects.
Freeze and Layer – Remember, it’s normal to see an insect or two from time to time as they speed up the compost process by breaking up organic material. They should not be found in large, visible numbers! If you face issues with insects, store green materials in a zip lock bag and keep it in a freezer. When you have enough for a thick layer of compost, add the bag’s contents into your bin, mix the same amount of browns, and layer on 1-2cm of soil. The soil layer acts as a barrier to manage excess insects.
Odour Control: A healthy compost bin should not emit foul odors. If you detect a bad smell, it’s often due to excess moisture, lack of oxygen, or an imbalance in materials. Adjust by adding more browns to absorb moisture and turning the compost to increase aeration.
Presence of Fungi: if you see mushrooms growing in your compost, your compost is a little too wet but the fungi actually speeds up the composting process. You can simply cut up the mushrooms, add more browns, stir to aerate the mix before putting a thin layer of soil to cover everything.

Fungi or mushrooms could appear in your compost but this is easily managed. (Source: Kaya Leaf)

Conclusion

Small container aerobic composting is an excellent way for gardeners in Singapore to contribute to a sustainable environment. If you don’t know where to start, here’s an example of a composter bin which I’ve been using, or you can easily make one yourself.

Try out this simple, yet effective and economical way to turn your kitchen waste into literally gold for your growing plants!

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