Composting at home is one of the easiest ways New Zealanders can cut what heads to landfill. Roughly a third of the average household's rubbish is food and garden waste, and when that material rots in a landfill it produces methane, a potent greenhouse gas. Composting at home keeps those scraps out of the red bin and turns them into free, rich material for your garden. Yet plenty of well-meaning gardeners hold back, worried that citrus, onion and cooked food will 'ruin' their compost. Most of those fears are myths worth busting.

Take citrus and onion first. The common claim is that they're too acidic and will kill the worms and microbes doing the hard work. In a worm farm (vermicomposting) there's some truth to going easy — worms don't love large volumes of highly acidic peel, and it can make a small bin sour. But in an ordinary garden compost heap, citrus and onion break down perfectly well. The key is moderation and balance: chop peels up small so they rot faster, and don't tip in a whole bucket of orange skins at once. Mix them through the pile rather than leaving a thick clump. If you're worried about acidity, a sprinkle of garden lime or plenty of 'brown' carbon material will keep things balanced.

Cooked food is the bigger, more legitimate concern — but again, it's about method rather than a flat 'never'. The real issue with cooked leftovers, meat, bones, dairy and oily food isn't that they can't decompose; it's that they attract rats, mice, flies and, in some areas, they can create smells. In an open compost bin these foods are best avoided or added only in small amounts and buried deep in the centre of the heap. If you want to compost all your cooked food and meat scraps, a sealed system like a Bokashi bin is designed exactly for that — it ferments everything, including meat and dairy, before you dig it into the garden or add it to your compost.

Good compost is really about balance between 'greens' and 'browns'. Greens are your nitrogen-rich, wet materials: vegetable scraps, citrus, onion, coffee grounds, grass clippings. Browns are carbon-rich and dry: dead leaves, shredded paper and cardboard, untreated sawdust, straw. Aim for roughly equal amounts by volume, keep the pile about as damp as a wrung-out sponge, and turn it every week or two to get air in. A well-fed, well-aerated heap heats up, breaks material down faster, and is far less likely to smell or attract pests — which quietly solves most of the citrus, onion and cooked-food worries in one go.

If home composting isn't practical for you, check what your local council offers. A growing number of areas now provide a kerbside food-scraps collection (often a green caddy or bin), and these accept things home systems struggle with — including cooked food, meat and bones — because they're processed at high-temperature commercial facilities. Rules vary considerably around the motu, so check your council website for what your service takes. Whichever route you choose, the takeaway is simple: citrus, onion and cooked food don't have to go to landfill. With a bit of balance, chopping and the right system, almost all of it can become something useful for your garden instead of methane in a tip.