Every week, a typical household throws away vegetable peels, coffee grounds, eggshells, and stale bread. In a landfill, that waste rots and releases methane, a powerful greenhouse gas. In a compost bin, the same scraps turn into dark, crumbly, sweet-smelling compost — the best free fertiliser a garden can get.
Composting is simply letting nature do what it already does on a forest floor: breaking down dead plant material into rich soil. You do not need a big garden, special equipment, or any experience to start.
What Is Compost, and Why Bother?
Compost is decomposed organic matter — kitchen scraps and garden waste that microbes, worms, and fungi have broken down into a dark, soil-like material. Gardeners call it “black gold” because it does so much for a garden:
- It feeds the soil. Compost adds nutrients slowly and steadily, without the risk of burning plants that chemical fertilisers carry.
- It improves soil structure. In heavy clay soil, compost loosens it and helps drainage. In sandy soil, it helps hold water and nutrients.
- It saves money. A bag of compost costs real money; your own is free, made from waste you were throwing away anyway.
- It cuts waste. About a third of household rubbish is compostable. Composting it means less rubbish to throw out and less waste going to landfill.
You do not need to be an expert. A compost pile is very forgiving, and even a neglected pile will eventually rot down — it just takes longer.
How Composting Works
Composting is not magic; it is biology. Tiny organisms — bacteria, fungi, and worms — eat the material in your pile and break it down. They need four things to work well: greens, browns, air, and water.
Greens are nitrogen-rich, moist material like fresh grass clippings and kitchen scraps. Browns are carbon-rich, dry material like dry leaves, shredded cardboard, and straw. The microbes also need oxygen, so the pile must not be packed down or waterlogged, and it should be damp like a wrung-out sponge — never soggy and never bone dry.
When these four are in balance, the pile heats up, the material breaks down fast, and you get finished compost in a few months. When they are out of balance, the pile still works — just more slowly.
Choosing a Compost Bin
You do not need to buy anything fancy. The right bin depends on your space.
A simple pile works if you have a garden corner. Just heap material in a pile about a metre wide and a metre tall. It is free, but it is slower and looks untidy.
A basic compost bin is the best choice for most beginners. A plastic bin with a lid and air vents costs little, keeps the pile neat, holds in heat and moisture, and keeps rats out. Any bin of 200 to 300 litres is a good size for a household.
A tumbler is a barrel on a stand that you spin to mix the contents. It makes compost faster and is easy to turn, but it costs more and holds less.
Place your bin on bare soil if you can, so worms and microbes can get in from below and excess water can drain away. Put it somewhere easy to reach — if the bin is hard to get to, you will stop using it. A spot with some shade is ideal, because full sun dries the pile out too fast.
Greens and Browns: The Golden Rule
The most important rule in composting is the balance between greens and browns.
Greens (nitrogen-rich): fruit and vegetable scraps, coffee grounds and tea bags, fresh grass clippings, green leaves, eggshells (crushed), and manure from plant-eating animals.
Browns (carbon-rich): dry leaves, shredded newspaper and cardboard, straw, dry twigs, sawdust from untreated wood, and shredded paper.
Aim for roughly two to three parts browns to one part greens by volume. Most beginner problems come from too many greens: the pile gets wet, slimy, and smelly. When in doubt, add more browns. A handful of shredded cardboard or dry leaves on top of every bucket of kitchen scraps keeps the balance right.
Chop or shred material before adding it. Smaller pieces break down much faster than whole ones, so tear up cardboard, chop thick stems, and crush eggshells.
What to Put In — and What to Keep Out
Yes, add these: fruit and vegetable peels and scraps; coffee grounds and filters, tea bags (remove any staples); eggshells (crushed); grass clippings and green leaves; dry leaves, straw, and shredded cardboard or newspaper; small twigs and prunings (chopped); old potting soil and spent plants.
No, keep these out: meat, fish, dairy, and cooked food — these attract rats and flies, and they smell as they rot. Diseased plants — some plant diseases survive composting, so bin them instead. Weeds with seeds or persistent roots — seeds can survive and sprout in your garden later. Treated or painted wood — the chemicals can poison your soil. Cat or dog waste — it can carry parasites that are not killed in a home compost pile. Glossy or coated paper, and plastic of any kind — these do not break down.
If you are unsure about something, leave it out. A safe pile is better than a fast pile.
Starting Your First Pile
- Put a layer of browns at the bottom — dry leaves or twigs about 10 cm deep. This gives the pile air and drainage.
- Add a layer of greens — a bucket of kitchen scraps or fresh grass clippings.
- Add another layer of browns on top. Always cover fresh kitchen scraps with browns. This stops smells and keeps flies away.
- Sprinkle with water if the material is dry. The pile should feel like a damp sponge.
- Keep layering as you add material, always finishing with a layer of browns on top.
That is it. Now let the microbes do the work.
Looking After the Pile
A compost pile needs very little attention, but a little care makes it much faster.
Turn it occasionally. Every two to four weeks, mix the pile with a garden fork, moving the outside material into the middle. Turning adds air, which speeds up the whole process and stops smells. If you use a tumbler, spin it a few times a week.
Keep it damp. In dry weather, water the pile lightly. In wet weather, cover it with a lid or a piece of old carpet to stop it getting soaked.
Watch the smell. A healthy compost pile smells like fresh earth. If it smells sour or like rotten eggs, it is too wet or has too many greens. Add dry browns and turn it — the smell will clear in a day or two.
Be patient. A well-kept pile can be ready in two to four months in warm weather. A neglected pile can take six months to a year. Both are fine — the end result is the same.
When Is Compost Ready, and How Do You Use It?
Finished compost is easy to recognise: it is dark brown or black, crumbly, and looks like rich soil; it smells earthy and pleasant, like a forest floor; you cannot recognise what went into it; and it feels cool, not warm, when you put your hand in it. If you still see recognisable bits, it is not ready — leave it for a few more weeks, or sieve it and throw the unfinished bits back into the bin.
Compost is a soil improver, not a replacement for soil, and a little goes a long way. Mix it into garden beds before planting — spread 5 to 8 cm over the surface and dig it into the top 15 cm of soil. Top-dress pots and containers with a 3 to 5 cm layer and let watering carry the nutrients down. Or mix one part compost to three parts potting mix for a rich container blend.
Do not use unfinished compost on seedlings or young plants. It can be too strong and can slow down germination. Only use finished, dark, earthy-smelling compost.
Common Beginner Mistakes
- Too many greens, not enough browns. This is the number one cause of smelly piles. Add dry leaves or shredded cardboard.
- Letting the pile dry out. A dry pile stops working completely. Water it until it feels like a damp sponge.
- Not covering kitchen scraps. Exposed food attracts flies and rats. Always cover scraps with a layer of browns.
- Making the pile too small. A pile needs a certain size to heat up — at least a cubic metre is ideal. Small piles still work, but more slowly.
Start Today
You can start composting today with what you already have. Save your vegetable peels from tonight’s dinner, tear up a cardboard box, and layer them in a bin or a corner of the garden. In a few months, that waste will be dark, crumbly compost feeding your plants for free.