How to Make Compost

Written by Ethlyn Koh
Photos by Syuhada Sapno

We are often hit with pangs of guilt when we dispose leftovers or other perishables that have been left sitting at the back of the refrigerator forgotten, overlooked or uneaten. 

According to the United Nations Food and Agriculture Association (FAO), an estimated 1.6 billion tonnes of food (worth $750 billion annually!) is wasted globally each year. In Malaysia alone, up to 16,688 tonnes of food waste is generated on a daily basis, an amount sufficient to feed 2.2 million mouths three meals a day.

The amount of food wasted globally would help feed twice the number of malnourished people across the globe, ending world hunger. 

However, wasting food not only comes with a financial and ethical cost, it too has impacts on the environment. Food wasted is equivalent to wasting all the energy and water invested into producing and processing, transporting, and packaging it, all the way until it reaches our plates. And if discarded food waste ends up in landfills to rot, a potent greenhouse gas 25 times more efficient at trapping heat than carbon dioxide known as methane would be released. Undeniably, reducing food waste can reduce our carbon footprint, reversing global warming. 

So what can we do about it?

A potential solution to minimise food waste ending up in landfills is composting. Composting is a method used to decompose organic solid wastes into simpler compounds with the help of microorganisms in the presence of air. The rotted organic material also known as compost, could be used to improve the quality of garden soil or even as a fertilizer for plants, reducing the need for chemical fertilizers. 

To begin, you require three simple ingredients – greens, browns and water. 

Greens refer to materials that are nitrogen-rich, crucial for microbial growth. Some examples include fruit and vegetable peelings, coffee grounds or filters, tea bags, and grass clippings.

Browns represent carbon-rich materials which provide aeration such as dry leaves, shredded paper or cardboard, egg boxes and egg shells.

Water keeps the compost pile moist, important for compost development.

When selecting your food scraps, avoid meat and dairy products which include fish bones, milk, yogurt, as well as oils and butter. These foods would cause bad odours to waft out of your compost, consequently attracting pests such as rodents and flies. Pet wastes (e.g. dog or cat faeces) and diseased plants should also be left out of the compost pile or bin to prevent the transfer of harmful pathogens back to plants or to humans. If you would like to compost these materials, you might want to look into the bokashi method.

Once you have collected and stored a good amount of kitchen and garden scraps, it is time to make the compost mix. Into your compost pile or bin, start layering your browns and greens. 

As green materials are typically wet and brown materials tend to be dry, you should always start the bottom layer with dry browns followed by a layer of wet greens, then just repeat the layering process until you run out of food scraps.

Step 5: Repeat step 1-4. It is all about layering! The ratio should approximately be two or three portions of browns to one portion of greens (3:1). 

Add a splash water to the browns to keep the compost mix nice and moist. Do not add too much water until the pile gets wet and soggy. If your compost is too wet, the sludgy mixture would not breakdown and will produce a foul odour. However, if it is too dry, microorganisms cannot decompose the materials effectively. Ideally, your compost needs to be moist for effective composting to occur. 

Once you are done, just sit back, relax and let the magic happen. In our Malaysian climate, the decomposition process usually takes anywhere between 4-6 months, depending on the temperature within your compost pile. The higher the temperature, the quicker your ‘black gold’ is produced. It is advisable to turn or rotate your compost pile using a spade or stick, preferably once a week to ensure everything is well aerated. 

So how do you know when your compost is ready? 

Finished compost tends to be dark and rich in colour, smells earthy (sometimes with a hint sweet or sour smell), and fluffy to the touch with a good moisture content just like a sponge. That is when you know it is good to go. If your compost smells like a dumpster or just bad in general, it might be too wet and have yet to decompose. Fret not, add more browns to soak up excess water or readjust the portions of browns to greens.

Composting is pretty experimental, so keep trying and don’t give up!