The Art and Science of Composting

Have you had a chance to truly immerse yourself in nature? Maybe during a walk in the forest, a hike in the hills, or while relaxing on the muddy banks of a river. Imagine being nestled in nature, surrounded by trees, feeling the soil beneath our feet! What marvels me about these ecosystems isn’t just the breath-taking view, but also, their ability to seamlessly function as a coherent unit. In nature, every player has a purpose. And, everything that comes from nature, goes back to it, to serve another purpose. So, if you’re munching on a fruit in the wilderness and drop your fruit peels and seeds onto the ground, you know they’ll be taken care of. The soil and it’s organisms will decompose them. Nature has engineered a top-notch mechanism to produce, use and organically recycle everything that comes from it, into valuable resources. All of this, without producing ANY “waste”. Genius, isn’t it?

However, in our cities, the waste we produce often ends up being discarded in dumping grounds, rivers or our neighbourhood. But, what if I told you this doesn’t have to be the fate of our waste? We can manage our waste and recycle more than 50% of it right at our homes. This is because the majority of waste we create in our homes in India is kitchen waste or biodegradable waste. This includes fruit and veggie peels, leftover food scraps, egg shells, tea leaves and coffee grounds. All of these materials come from nature and can go back to nature through an easy method called composting. Through the process of composting, our food scraps turn into nutrient-rich food for plants, thereby completing the circle of life!

Before delving into the “how” of composting, let’s understand its benefits and its role in combating climate change.

• Reduces the burden on our landfills: Many dumping grounds in cities across India are severely overburdened and running overcapacity. If we started composting, the burden on our dumping grounds would reduce significantly!
• Decreases greenhouse gas emissions: When food rots in landfills, it breaks down anaerobically (without oxygen) and releases methane, a greenhouse gas that is 25 times more potent at warming the earth than carbon dioxide. Ugh. We can avoid this by simply composting at home. Additionally, if we composted at home, our biodegradable waste doesn’t need to be transported across large distances for dumping/ processing. This further reduces vehicular CO2 emissions.
• Prevents water pollution: Fruits and vegetables have a high water content (approx 70 to 90%). When mixed waste is discarded in landfills, this water from the rotting organics can react with metals in the landfill to produce toxic leachate that causes groundwater pollution.
• Improves soil quality: Compost is packed with beneficial nutrients and minerals that are essential for plant growth. Compost also helps the soil breathe more easily and helps retain moisture. This allows us to reduce the amount of water we use for watering plants.

There are different ways of composting, though I find it’s easiest to get started with Aerobic composting. It’s essential to note that the heroes of the composting process are nature’s hardworking microorganisms (including bacteria and fungi). And, by setting up a composting system, we are simply creating the right conditions for them to get to work and convert our food scraps into compost.

Microorganisms are ubiquitous and the compost pit is like a massive buffet for these little guys to feast on. Just like us, these microorganisms need a balanced diet to function efficiently. And the way to prepare this meal for them is to balance the proportion of carbon and nitrogen in the composter. Nitrogen is required for microbial growth and reproduction, while carbon serves as an energy source. Our kitchen food scraps (veggie peels, coffee grounds, etc) are rich in Nitrogen and are often referred to as ‘greens’. These greens need to be balanced with carbon-rich materials such as dried leaves, cocopeat, sawdust, which are also known as ‘browns’.

So how to get started?

1. Get a composter: You can order one from brands like Dailydump, Smartbin Air or you can even make your own DIY version by drilling some holes in a bucket. Here’s a reference video.
2. Add food scraps and cover it with browns: Drop your food scraps (aka greens) into the composter daily and cover with a layer of cocopeat/ crushed dry leaves/saw dust (aka browns). As a thumb rule, a good ratio of browns to greens is 2:1. So for every part of food scraps/ kitchen waste, remember to add double the amount of browns.
3. Add microbes: Add some microbial culture to your composter once a week or so to help speed up the process. Most composters come with the microbial culture along with the order. Or you can order it separately from brands such as Dailydump. You can also use sour buttermilk instead.
4. Stir the contents: Since this is an aerobic process, give it an occasional stir to let oxygen in to speed up the process. Once full, keep the pot to rest and repeat the process in another pot. In about 3–4 weeks, your first batch of compost will be ready!

But is just a balanced diet enough? What other factors can help our microbe friends work more efficiently?

Just like us, our microbe buddies also require other abiotic factors to thrive such as water and oxygen.

Image source: On-farm Composting Handbook by Robert Rynk

Oxygen: Our hardworking microbes and fungi helpers are generally aerobic. i.e. they require oxygen for the breakdown process. If oxygen supplies are depleted, the composting process becomes anaerobic and produces undesirable odours. So the next time you start to suspect that the process is turning anaerobic, remember to pick up your rake and give it a little mix to let the oxygen in.

Moisture: Microorganisms are able to decompose organic matter much faster when the pile has optimum moisture content. When moisture levels drop below 35–40%, their activity gets inhibited. On the other hand, if moisture levels shoot above 65%, it leads to other problems such as nutrient leaching, slow decomposition and odour formation. So if your pile seems a little too wet, remember to add some brown matter. And if your pile looks too parched, you can sprinkle some water to revive it.

Particle size: Imagine having to gulp down all your food without having the option to chew it! Having teeth to help break this down into smaller morsels makes it so much easier for digestion. This is because as surface area increases, the easier it becomes to work on the particles. Similarly, while tossing our greens into the compost bin, try to make sure these are not too bulky, so microbes can break this down more easily.

And last but not the least, did I mention a balanced diet already? Well, being the biology enthusiast that I am, I want to make sure our little guys are fed well. So here’s one last (scientific) reminder why it’s SO important!

Balanced diet a.k.a. C:N ratios: Nitrogen and carbon are the building blocks of living cells. 50% of a microbes’ cell body consists of carbon while nitrogen is a critical element for synthesizing proteins, enzymes and DNA. If there’s too much nitrogen, the microorganisms can’t use it all at once and the excess is lost in the form of ammonia gas (not the best to smell :P). On the other hand, if there’s too much carbon, the process of composting slows down. But don’t fret, in a couple of tries, you’ll acquire all the tacit knowledge you need to be a composting ninja!

And, if you’re still reading this article, I’m going to consider that as a win already! I hope this information encourages you to want to experience the joy of composting first hand and nudges you to embark upon your journey of living more sustainably. So go ahead, brew a magic pot of black gold yourself and let us know how it worked out for you.

Happy Composting :)