How a Compost Heap Works
A compost heap is a pile of organic waste — food scraps, dead leaves, grass clippings — that tiny living things slowly break down into compost, a dark, crumbly material that feeds plants. It works because microbes, worms, and other decomposers eat the waste and turn it into nutrient-rich soil over about six to twelve weeks.
Composting matters because it cuts down on rubbish sent to incinerators or landfills and recycles nutrients straight back into the garden. A healthy heap needs the right balance: wet, nitrogen-rich 'greens' (fruit peels, vegetable scraps, grass) for energy and dry, carbon-rich 'browns' (dead leaves, twigs, paper) for air and structure — with more browns than greens, plus a little water to keep it damp.
Learners come away understanding that decomposition is done by living helpers, not magic; that warmth, air, and moisture speed it up; and that food and plant matter belong in the heap while plastic, metal, and meat do not.
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A magic rubbish recipe🍂🪱🌱 Composting How a compost heap works A compost heap is like a slow, gentle kitchen for tiny living things. We feed it old food scraps and dead leaves, and over a few weeks it turns them into rich, crumbly soil-food called compost. Instead of throwing fruit peels and leaves into the rubbish bin, we let nature recycle them. Gardeners in Singapore use the finished compost to help their plants grow strong. 🌿 Tap Next to start cooking up some compost!
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Greens and BrownsTwo kinds of food for the heap A healthy heap needs a mix of two things. Tap each box to peek inside! 🥬 GREENS Wet & juicy: fruit peels, veggie scraps, grass cuttings. They give nitrogen — the energy food. 🍌🍎 🍂 BROWNS Dry & papery: dead leaves, twigs, cardboard. They give carbon and let air sneak in. 🍃📦 The secret recipe: use a bit more browns than greens. Too many wet greens makes a smelly, soggy heap — yuck! 🤢 Tap both boxes to reveal them.
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Can it go in?Sort the scraps! 🗑️ Tap a scrap to pick it up, then tap the bin it belongs in. Compost loves food and plant bits — but NOT plastic, metal or meat! 🍌Banana peel 🍂Dead leaves 🥤Plastic cup 🥚Eggshell 🔋Battery 🍎Apple core 🟢Compost heap 🗑️Rubbish bin Pick a scrap first. 👆
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Build a healthy heapLayer it up! 🥪 A great heap is like a layered sandwich. Add layers and aim for more browns than greens, plus a splash of water to keep it damp. 🍂 Browns 🥬 Greens 💧 Water Browns: 0 · Greens: 0 · Water: 0 Check my heap ✔ Try about 4 browns, 2 greens and 1 water. 🌡️
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The hungry helpersWho does the work? 🔬 You don't stir magic in — tiny living helpers eat the scraps and break them down. Tap each helper to meet them! Microbes Too tiny to see! Billions of bacteria & fungi munch the scraps and make the heap warm. 🔥 Worms Wrigglers eat rotting bits and tunnel about, mixing in air and pooping out lovely soil. 🪱 Bugs Beetles, sowbugs & mites chew big bits into smaller bits so the microbes can finish the job. 🐛 Meet all three helpers above.
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Watch it changeSlide through time ⏳ The helpers need warmth, air and a little patience. Drag the slider to watch chunky scraps turn into dark compost. Week 1 Fresh scraps! Everything is colourful and chunky.
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The rewardBlack gold for plants 🌻 After about 6–12 weeks the heap becomes compost: dark, crumbly and sweet-smelling like a forest floor. 🌱➡️🪴 Mix it into garden soil. The compost feeds plants, holds water, and helps roots grow — all from yesterday's banana peels! Less rubbish goes to the incinerator. Plants get free, gentle food. Nature's recycling, done by you.
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You're a compost champ!🏆🪱🌿 What you learned Greens + Browns: wet scraps for energy, dry leaves for air & carbon — use more browns. Sort it right: food & plant bits go in; plastic, metal and batteries stay out. Tiny helpers — microbes, worms and bugs — eat the scraps and break them down. With warmth, air, water and time, the heap becomes rich compost for plants. Well done! 🎉 Next time you finish a banana, you'll know it could become a brand-new plant. Will you start a compost heap at home or in school?
Frequently asked questions
- What can you put in a compost heap?
- Fruit and vegetable scraps, peels, grass cuttings, dead leaves, twigs, and plain paper all belong in a compost heap. Keep out plastic, metal, glass, and meat, as these do not break down well and can attract pests.
- How long does it take to make compost?
- A compost heap usually takes about six to twelve weeks to turn scraps into finished compost. Warmth, air, and moisture speed things up, while a cold or dry heap breaks down more slowly.
- What are 'greens' and 'browns' in composting?
- Greens are wet, nitrogen-rich materials like fruit peels, vegetable scraps, and grass that give the heap energy. Browns are dry, carbon-rich materials like dead leaves and paper that add air and structure. A healthy heap uses more browns than greens.
- What actually breaks down the food in a compost heap?
- Tiny living helpers do the work: microbes too small to see, plus worms, insects, and fungi. They eat the scraps and break them down into compost — you don't have to stir in anything magic.
- Why is compost good for plants?
- Finished compost is dark, crumbly, and full of nutrients, so mixing it into garden soil helps plants grow strong. It also helps the soil hold water and feeds the living things that keep soil healthy.
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