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To compost at home, mix roughly 2–3 parts browns (dry leaves, cardboard, straw) to 1 part greens (food scraps, grass clippings) by volume, keep the pile as damp as a wrung-out sponge, and turn it every week or two. Finished compost is dark, crumbly and smells like soil, and it takes about 2 to 12 months depending on the method.
What composting is and why it works
Composting is controlled rotting. You pile up plant scraps and yard waste, and bacteria, fungi, worms and insects break them down into a dark, crumbly material called humus-rich compost. It happens in any pile of leaves on its own. Composting just makes it faster, tidier and free of bad smells.
The microbes doing the work need four things:
- Carbon for energy. It comes from dry, brown material: leaves, straw, cardboard, wood chips.
- Nitrogen to build their bodies. It comes from fresh, green material: food scraps, coffee grounds, grass clippings.
- Water, about as much as a wrung-out sponge holds.
- Air, because the microbes that make compost without bad smells breathe oxygen.
That is the whole theory. Get carbon and nitrogen roughly in balance, keep it damp, let air in, and the pile does the rest. Scientists describe the balance as a carbon-to-nitrogen (C:N) ratio of about 25–30:1. At home you don’t need to calculate it: about 2 to 3 buckets of browns for every bucket of greens gets you there. The compost mix calculator does the arithmetic if you want a check.
Choosing a composting method
There is no best method, only the one that fits your space, your waste and how much effort you want to put in. Most people with a yard start with a bin or an open pile. People in apartments start with worms or bokashi.
| Method | Space needed | Cost | Speed | Effort | Smell risk | Handles |
|---|---|---|---|---|---|---|
| Open pile | About 3 × 3 ft (1 × 1 m) of yard | Free | 3–12 months, longer if left alone | Low to medium | Low if balanced | Yard waste, plant-based kitchen scraps |
| Enclosed bin | About 3 × 3 ft (1 × 1 m) | Free (DIY) to about $150 | 3–12 months, longer if left alone | Low to medium | Low | Same as a pile, tidier, fewer pests |
| Tumbler | Patio or small yard | About $80–$300 | 2–4 months per batch | Medium (turning) | Medium if too wet | Kitchen scraps, some yard waste |
| Worm bin | Under a sink, garage, balcony | About $30–$150 | 2–6 months | Low | Low if not overfed | Fruit and vegetable scraps, coffee, paper |
| Bokashi | A bucket in the kitchen | About $40–$80 plus bran | 2 weeks ferment + 2–4 weeks in soil | Low | Sour smell when opened | Almost all food scraps, including meat and dairy |
| Municipal or drop-off | None | Free to a small fee | Not your problem | Very low | None at home | Whatever your program accepts |
Costs are rough US retail ranges. Costs and times vary by region, brand and effort. For a closer look at the three backyard options, read compost bin vs tumbler vs pile. For indoor options, see vermicomposting, bokashi composting and composting in an apartment.
Greens and browns: what to put in
Everything you compost falls into one of two groups. Greens are wet and rich in nitrogen. Browns are dry and rich in carbon. The color is a rough guide only: coffee grounds are brown but count as a green, and dry hay is green-ish but counts as a brown.
| Greens (nitrogen, wet) | Browns (carbon, dry) |
|---|---|
| Fruit and vegetable scraps | Dry leaves |
| Coffee grounds and paper filters | Cardboard, torn up |
| Tea leaves and plastic-free tea bags | Newspaper, shredded |
| Grass clippings | Straw and hay |
| Banana peels | Wood chips |
| Citrus peels | Sawdust from untreated wood |
| Onion and garlic skins | Pine needles |
| Hair and fur, spread thin | Paper towels and napkins |
| Weeds that haven’t gone to seed | Nut shells |
| Green garden trimmings | Egg cartons (plain cardboard) |
| Houseplant and flower trimmings | Dry stalks and stems |
| Horse manure (with care) | Shredded plain paper |
| Chicken manure (with care) | Corn cobs, chopped |
| Fresh plant-based kitchen waste | Dryer lint from natural fibers |
| Seaweed, rinsed | Corn stalks |
| Spent annual flowers and vegetable plants | Brown paper bags, torn up |
The ratio to aim for is about 2 to 3 parts browns to 1 part green by volume. Most households produce far more greens than browns in summer and far more browns in fall. Keep a bag of dry leaves or a stack of cardboard next to the bin so you always have browns to cover each load of scraps.
Eggshells are neither: they add minerals, not much carbon or nitrogen, so crush them and add them freely. Not sure about a specific item? The A–Z list of what you can compost covers 40 common materials with a yes, with-care or no verdict for each.
What not to compost
Some things attract pests, spread disease, or never break down in a home pile. Keep them out of a backyard bin.
| Don’t add | Why | Instead |
|---|---|---|
| Meat and fish | Smell, attract rats, raccoons and dogs | Bokashi, or municipal food-scrap collection |
| Dairy and cheese | Smell and pests | Bokashi, or municipal collection |
| Cooking oil and greasy food | Coats material, slows everything, attracts pests | Cool, seal and trash small amounts; some cities collect oil |
| Dog and cat poop, used cat litter | Parasites and pathogens a home pile won’t reliably kill | Trash, or a dedicated pet-waste digester away from food crops |
| Diseased plants | Most home piles don’t get hot enough to kill disease | Trash or municipal yard waste |
| Charcoal ash | Briquettes contain additives | Trash once fully cold |
| Glossy paper and receipts | Coatings and chemical developers | Recycling (glossy), trash (receipts) |
| Plastic, “biodegradable” plastic bags | Don’t break down in a home pile | Trash, or industrial composting if certified |
| Treated or painted wood, sawdust from it | Preservatives and paint residues | Trash or hazardous waste drop-off |
| Weeds in seed, invasive roots | Seeds and roots survive cool piles | Hot compost them, or trash |
Some items sit in between: bread, rice and pasta, cooked food, wood ash and compostable plastics are all possible with care. Each linked page explains when and how.
Setting it up
Pick the spot. Choose level ground with good drainage, part sun or part shade, and close enough to the kitchen that you’ll actually walk there in the rain. Put it directly on soil, not concrete, so worms and microbes can move in. Keep it a few feet from fences and wooden walls.
Get the size right. A pile or bin of about 3 × 3 × 3 feet (1 × 1 × 1 m) is the sweet spot. Smaller piles lose heat and dry out. Much bigger piles are hard to turn and can run short of air in the middle.
Start with a base layer. Lay 4 to 6 inches (10–15 cm) of coarse browns, such as twigs, straw or corn stalks. It lets air in from below and helps drainage.
Build the first fill. Add greens and browns in roughly 2–3 to 1 proportion. You can layer them like lasagna, but mixing them together works better, because the microbes need both in the same place. Water each layer lightly as you go until everything feels damp, not dripping.
Cover the scraps. Always finish with a layer of browns on top. It hides food from flies and animals and stops smells.
The full walkthrough, with a week-by-week table for the first month, is in how to start a compost pile.
Keeping it going
Moisture. Squeeze a handful from the middle. A few drops of water is right. If it drips, it’s too wet: add browns and turn it. If it crumbles dry, water it while you turn it. Piles dry out fast in summer and get soggy in rainy months, so check every week or two.
Turning. Turning adds air and mixes the outside into the center, where most of the work happens. Every 1 to 2 weeks is plenty for most people. Turn more often if you want speed; turn less if you’re happy to wait. A garden fork or a compost aerator tool does the job.
Size of the pieces. Smaller pieces break down faster. Chop big scraps, shred leaves with a mower, and tear cardboard. You don’t need to be precise; a whole squash just takes longer than a chopped one.
Adding new material. Bury fresh scraps in the middle of the pile and cover them with browns. Or keep two bins: fill one while the other finishes.
Want it faster? A big, balanced, well-watered pile turned every few days can heat up to about 130–160°F (55–70°C) and finish in weeks rather than months. See hot composting.
Troubleshooting
Most compost problems come down to the same few causes: too wet, too dry, too small, or out of balance.
| Problem | Likely cause | Fix |
|---|---|---|
| Smells like rotten eggs or garbage | Too wet, too many greens, no air | Mix in dry browns, turn the pile, add drainage |
| Smells like ammonia | Too much nitrogen (grass, manure) | Add browns (leaves, cardboard, straw) and turn |
| Soggy and slimy | Too wet, compacted | Add coarse browns, turn, cover from heavy rain |
| Dry, nothing happening | Too little water | Water while turning until damp like a wrung-out sponge |
| Not heating up | Too small, too dry, or too few greens | Build to about 3 × 3 × 3 ft (1 m³), add greens, water |
| Fruit flies | Exposed food scraps | Bury scraps in the center, cover with 2 in (5 cm) of browns |
| Rats or raccoons | Meat, dairy, oily food, open access | Remove those foods, use a closed bin with mesh base |
| Very slow | Big pieces, too many browns, cold weather | Chop or shred, add greens, turn more often |
Smell problems get their own page: why does my compost smell?
When it’s ready and how to use it
Finished compost is dark brown, crumbly, and smells like a forest floor. You shouldn’t be able to recognize most of what went in, although eggshells, avocado pits and woody bits often survive. The pile will have shrunk by about half or more.
To test it, put a handful in a sealed bag for a few days. If it smells sour or ammonia-like when you open it, it needs longer. Many gardeners also let finished compost cure for 2 to 4 weeks before using it around young plants.
Screen it through a ½-inch (12 mm) mesh if you want a fine texture, and toss the lumps back into the active pile. Then:
- New beds: mix in 2–3 inches (5–8 cm) of compost.
- Established beds: spread 1–2 inches (2–5 cm) on top each spring or fall.
- Containers: blend about 20–30% compost into potting mix. Compost alone is too dense for pots.
- Lawns: rake in a thin layer, about ¼ to ½ inch (6–12 mm).
The full guide, with a compost vs mulch vs fertilizer table, is how to use compost. And for timing by method, see how long does compost take?
Composting through the seasons
Fall is the season of browns. Leaves pour in and greens thin out. Shred the leaves with a mower, add as many as your greens can balance, and bag the rest to use as browns through next summer. Composting leaves covers how many a pile can take and when to make leaf mold instead.
Winter slows everything down. Below about 40°F (4°C) the microbes nearly stop, and in cold regions the pile freezes solid. That’s fine. Keep adding scraps and covering them with browns; freezing and thawing breaks them down, and the pile restarts in spring. A bigger pile or an insulated bin stays active longer. See composting in winter.
Spring is restart time. Turn the pile as soon as it thaws, mix in fresh greens such as the first grass clippings, and water it if it’s dry. Anything finished over winter goes straight onto beds before planting.
Summer is peak speed. Piles can finish in a couple of months, but they also dry out fast. Water during dry spells and keep a supply of browns to balance heavy loads of grass clippings.
Rot happens.
You're just helping it along. No purism, no guilt: a slightly wrong pile still turns into compost.
Frequently asked questions
How long does composting take?
About 2 to 12 months for most home setups. A hot, well-balanced pile that you turn often can finish in 1 to 3 months; a pile you leave alone takes 6 to 24 months. See how long compost takes for a method-by-method table.
Can you compost in an apartment?
Yes. A worm bin or a bokashi bucket fits under a sink or on a balcony, and many cities run food-scrap drop-offs. See composting in an apartment for the options side by side.
Do you need worms to compost?
No. An outdoor pile or bin is colonized by bacteria, fungi and soil animals on its own. Worm bins (vermicomposting) are a separate method that suits small spaces and indoor use.
Can you compost citrus peels?
Yes, in an outdoor pile or bin. Chop them and mix them in; they break down more slowly than most scraps. Worms dislike citrus, so add only small amounts to a worm bin. More on citrus.
Why does my compost smell?
A bad smell almost always means too much wet green material and not enough air. Mix in dry browns such as shredded leaves or cardboard and turn the pile. Healthy compost smells earthy. Full troubleshooting.
Can you compost paper?
Plain paper, newspaper, paper towels and cardboard are all browns and compost well when shredded or torn. Skip glossy, coated paper and thermal receipts. See cardboard and receipts.
Does a compost bin attract rats?
Only when it offers food and shelter. Keep meat, fish, dairy and oily food out, bury fresh scraps in the center of the pile, and use a closed bin with a wire mesh base if rodents are common where you live.
What is the ratio of browns to greens in compost?
Roughly 2 to 3 parts browns to 1 part greens by volume. That lands the mix near a carbon-to-nitrogen ratio of about 25–30:1, which is the range most extension guides recommend. The compost mix calculator checks your mix for you.
Can you compost in winter?
Yes. The pile slows down or freezes in cold weather, but you can keep adding scraps all winter and it restarts in spring. A bigger pile or an insulated bin stays active longer. See composting in winter.
Is compost the same as fertilizer?
No. Compost is a soil amendment: it feeds soil life, improves structure and holds water, and it releases nutrients slowly. Fertilizer delivers concentrated nutrients. Many gardens use both. How to use compost.