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The ABC of composting

During composting, organic matter breaks down into nitrogen and carbon, and when these two are balanced, you get compost.  

Every week, newspapers carry articles about the smog at Pallikaranai and Perungudi, created by the trash burning in the landfills. Sadly, more than 80 per cent of the waste is organic, which can be diverted from the landfill simply by composting.

Organic waste includes waste from the kitchen, leftover food, leaves and flowers. Composting is the process of breaking down organic matter into nutrient-rich humus. It is different from rotting because while rotting is decay, accompanied by putrid smell and fungus, composting is slow decomposition — the process that takes place in forests, where layers of leaves slowly break down to become part of the loamy soil, giving you that “forest smell”.

Science behind composting

During composting, organic matter breaks down into nitrogen and carbon, and when these two are balanced, you get compost. Too much nitrogen will make the matter rot; too much carbon makes the mix dry and inert.

Nitrogen comes from the green waste — vegetable and fruit peels, flowers, leftover food. Carbon comes from the brown waste — dry leaves that fall from trees, shredded cardboard, brown coconut shreds (not the shell).

While composting can be aerobic or anaerobic, the simplest way to compost involves air, introduced into the mix through vents in the composting bin and through an occasional stir.

Composting at home

For starters, you need a container — drum, terracotta pot, khamba, plastic bucket…. Whatever you use, just make holes at regular intervals for air circulation.

Collect all green waste and deposit into the composting bin once or twice a day. If possible, chop peels and other waste into small pieces for faster composting. Now, gather the brown waste together.

For every handful of kitchen or ‘green’ waste, add a handful of ‘brown’ waste. Ensure that a layer of browns covers the top layer of the pot. Cover the composting pot tightly, so that small creatures can’t get in. Place a plate underneath to collect any liquid that flows out.

As the mixture starts to break down, a brownish liquid oozes out, which is the leachate. It is very high in nutrients and can be used as liquid fertilizer when diluted (1 part leachate to 30 parts water).

You can give it a boost by inoculating the mixture with a spoon of yoghurt, panchakavya or cow dung slurry. This adds microbes to kick-start the composting.

Keep adding ‘green’ and ‘brown’ waste to the pot till it fills up. Then start another pot. Every two or three days, stir to add air into the mix. Leave the filled pot closed to “sit”. After six to eight weeks, when you open the pot, it will smell like damp earth ( mann vasanai). Your brown gold is ready to feed your plants.

Avoid these in compost

Coconut shells, mango seeds and peanut shells take nearly a year to decompose. If you add these to the mixture, they create anaerobic pockets that will start to smell. Dairy attracts rodents. Bones take a long time to decompose, so can be avoided. Crushed eggshells are a wonderful source of calcium and can be directly added to the planting soil, as can tea and coffee dregs.

Troubleshooting

Compost is neither wet nor dry, and should smell like damp earth. If your pot looks soggy, it means there’s too much nitrogen. Toss in some browns. If it looks dry, then add a dose of green waste. The most problems happen when the compost is soggy.

Maggots will start to multiply in the compost. White worms or black grubs are creepy (you can even hear them sometimes) and have stopped many people from further composting. But the solution is easy. Add turmeric and chilli powder and then add sawdust, coco peat or dry leaves to draw out the moisture. Again, it’s all about the balance between greens and browns.

Fruit flies, from fruit and vegetable peels, become adults in your compost bin if the conditions are wet. Add dry leaves and make sure the compost drum is covered with a lid.

Bad odours are usually because the mix is too damp. But it could also be because something is blocking the circulation of air. Ensure that there is no plastic, coconut shells, or mango seeds in the compost drum.

Not much effort

You don’t need a lot of space or time to compost. It takes five minutes a day. It is important to remind yourself that the easiest thing to do with composting is to give it up. The most rewarding thing is to smell and feel the earth, and to know that you made a contribution to healthy plants and to keeping resources out of landfills.

Courtesy: The Magic Bean

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Printable version | Oct 18, 2020 8:10:27 PM | https://www.thehindu.com/features/homes-and-gardens/the-abc-of-composting/article6941102.ece

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