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Image: Tina Tiller
Image: Tina Tiller

PartnersMarch 12, 2024

How to compost for every living situation

Image: Tina Tiller
Image: Tina Tiller

You don’t need to have green thumbs – or a garden – to compost your food scraps.

The worms came in an ice cream box. Peeking under the lid, I spied my new pink, wriggly flatmates – all 1,000 of them. After depositing them in their new home – a multi-tiered worm “apartment block” in the courtyard of my Dunedin flat, the worms happily munched on potato peels and capsicum cores for about a year, before they moved to a new student flat.

Since then I’ve shared a backyard compost bin with resident redback spiders in Australia, and grappled with the stinkfest rubbish room in an apartment building.

Finding a food scraps system that fits into your home and lifestyle – that doesn’t involve just chucking it in the rubbish bin – can take some finessing. But there are important reasons to make it work: we can’t let that nutrient-laden goodness go to waste. Compost can boost the carbon-storing superpowers of our soil, plus diverting food scraps from landfill avoids releasing potent planet-heating methane gas. Currently, about half of what Aucklanders send to landfill could actually be composted.

“It’s a do-good action,” says Judy Keats, a composting expert from the Compost Collective. No matter your living situation or lifestyle, here’s how composting can work for you.

For people with gardens: The classic compost bin

If you have space in a backyard or garden, a compost bin is “one of the easiest systems to use,” says Keats. “You can’t really go wrong.” You can buy a compost bin for pretty cheap (especially if you score a Compost Collective discount) or DIY with chicken wire or pallets.

Then it’s a matter of depositing your greens (fresh food scraps, grass clippings) and browns (cardboard, autumn leaves) in a roughly 50:50 proportion. “That’s where people fall down. They just have so much green material going in. We need to balance that out,” explains Keats.

Adding browns will make decomposition more efficient, and help maintain the oxygen-loving microorganisms that keep your compost smelling sweet and earthy, rather than like rotten eggs.

It will take about four months of regular additions for the compost at the bottom to transform into a dark brown sticky crumb called humus – which you can add to your own garden, or list on ShareWaste NZ for a neighbour to pick up if you don’t have green thumbs. Alternatively, you can take the lazy option: “you can leave it and it will just keep breaking down,” says Keats.

Bonus: The in-ground worm farm is a neat option for those keen on gardening. Simply dig a bucket with holes drilled in its sides into your veggie patch. “The holes allow the worms to move in and out and excrete throughout the root zone of the garden bed,” says Keats. 

A worm farm in action (Image: Compost Collective)

For people with less green space: Worm farm

If you lack backyard space for a compost bin – or the green garden waste to feed it – a worm farm could be the perfect match for you. A compact worm farm can fit neatly on a shady balcony or courtyard. 

Worms will gobble up fresh food scraps and shredded, dampened cardboard, but aren’t big fans of bread, meat, acidic foods like citrus, or hot spicy chillies. 

“Worm farms are suited to young families because the kids get involved. They’re intrigued by the worms,” says Keats. 

For apartment dwellers: Benchtop bokashi

For those tight on space, the bokashi is your new best friend. A sealed bucket that sits on your bench indoors, it’s “our fermentation or pickling system. We’re keeping the air out,” Keats explains.

Add your food scraps – including cooked food, mouldy cheese, and meats, but no liquids – to the top bucket. Then collect the juice from the bottom bucket (you can use this to feed your houseplants, or pour down the drain to balance PH). 

About once a month you’ll have to get rid of the solid block from the top bucket – for folks without their own compost bin, you can find a local hub where “they’re turned into high quality compost.”

For lifestyle blocks: Freestanding heaps

If you’ve got lots of space to grow, consider creating a freestanding compost pile directly on the garden bed to enrich the soil and keep the moisture in. Keats also extols the virtues of a bathtub worm farm: “all the community gardens I’ve worked in over the years have a bathtub worm farm, and they’re very, very good.”

Make it work for you: Build a combo

In addition to the space you have available, your individual waste stream might mean a combination of solutions works for you. “If you eat a lot of takeaways and have lots of meat, rice and bread, that kind of waste can be pre-digested through a bokashi system before it goes in your compost bin,” Keats explains. But ultimately, you don’t need to compost perfectly. “People might just feel good about getting rid of 80%, 90% of their food waste. The kerbside collection can take those last little bits.”

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