To compost at home, mix carbon-rich browns (dry leaves, shredded cardboard) with nitrogen-rich greens (fruit and vegetable scraps, coffee grounds), keep the mix as damp as a wrung-out sponge, and turn it regularly to let air in. The U.S. Environmental Protection Agency recommends at least two to three times as much brown material as green by volume, and says a well-maintained pile is ready in about three to five months, while an untended one can take a year.
Most failed compost piles come down to the same few problems: too wet, too dry, the wrong mix, or the wrong materials. This guide gives you the numbers from the EPA and university extension services, shows where those sources disagree, and helps you pick the right method for a yard, a balcony or an apartment.
How Much Brown vs. Green Material?
Every compost recipe balances two kinds of material. Browns are dry and carbon-rich: fallen leaves, straw, shredded paper and cardboard. Greens are moist and nitrogen-rich: fruit and vegetable scraps, coffee grounds and fresh grass clippings. How much of each to use is where trusted sources don’t fully agree:
| Source | Browns : greens | How they say it |
|---|---|---|
| U.S. EPA | 2 to 3 : 1 | At least two to three times the volume of browns to greens |
| NC State Extension | 2 : 1 | A simple recipe: a 2-to-1 mix of browns and greens |
| University of Illinois Extension | 1 : 1 | 1 part green to 1 part brown material |
Our practical takeaway
Start in the middle, at about 2 parts browns to 1 part greens, then let the pile tell you. If it gets wet and smelly, add browns. If it stays dry and cold, add greens and water. Kitchen scraps are wetter than leaves, so a kitchen-heavy pile usually needs the higher end of the brown range.
What Can and Can’t Go in Compost
Compost these
- Fruit and vegetable scraps
- Coffee grounds and paper filters
- Crushed eggshells
- Grass clippings, dry leaves, plant stalks and twigs
- Shredded uncoated paper and cardboard
- Untreated wood chips
Keep these out
- Meat, fish and bones
- Cheese and other dairy
- Fats, oils and grease
- Pet waste and cat litter
- Diseased or pest-infested plants
- Treated wood, glossy paper, produce stickers
Source: U.S. EPA, “Composting At Home”. The EPA notes that meat, dairy and fats attract animals and don’t fully break down in a backyard pile.
Never compost dog or cat waste
NC State Extension lists dog and cat feces, litter and dirty diapers among the materials to keep out because they may contain parasites and pathogens. Bag them for the trash instead.
Choose a Method: Pile, Tumbler, Worms or Bokashi
| Method | Best for | Key facts |
|---|---|---|
| Open pile or bin | Yards with leaves and kitchen scraps | Most efficient at 3 to 5 feet on each side (Illinois Extension); ready in about 3 to 5 months when maintained (EPA) |
| Tumbler | Small yards, keeping scraps contained | Easy to mix, but can stay wet and slow; an Oregon State Extension expert finishes tumbler material in a turned pile |
| Worm bin | Apartments and indoor kitchens | Uses red wigglers (Eisenia fetida) kept at 59 to 77°F (NC State Extension) |
| Bokashi | Small spaces, cooked food, meat and dairy | Ferments scraps in a sealed bucket for about 10 to 14 days, then must be buried or added to compost (WSU Extension) |
What is a compost tumbler, and does it work?
A compost tumbler is a closed drum on a stand that you rotate to mix the contents, instead of turning a pile with a fork. It keeps scraps tidy and away from animals. Expectations matter, though: a composting expert answering for Oregon State University Extension calls it “a very slow process”, warns that tumblers leak dark liquid when loaded with food scraps or grass clippings, and suggests starting with dry leaves or straw to soak up moisture. The same expert recommends sturdy, larger models over small two-chamber designs.
No yard? Use worms or bokashi
For an apartment, a worm bin works indoors as long as it stays between 59 and 77°F, the range NC State Extension gives for red wigglers. Washington State University Extension describes bokashi as a sealed fermentation system that can take meat, dairy and cooked food. After 10 to 14 days of fermenting, you bury it 8 to 12 inches deep and wait at least 2 weeks in warm soil (3 to 4 weeks in cool soil) before planting there. Drain the liquid every few days to prevent odors.
How to Start a Compost Pile Step by Step
- Pick the spot. Choose a level, well-drained place you can reach easily from the kitchen and garden.
- Collect browns first. Stockpile dry leaves, straw or shredded cardboard. You will need more browns than greens.
- Build big enough to heat. NC State Extension recommends a pile at least 3 feet high and 3 feet across so it insulates itself; Illinois Extension gives 3 to 5 feet on each side as the most efficient size.
- Mix browns and greens. Aim for roughly 2 to 3 parts browns to 1 part greens, and bury fresh kitchen scraps under browns.
- Add water as you go. The whole pile should feel like a wrung-out sponge (EPA).
- Turn it. Move material from the outside to the center. NC State Extension suggests weekly mixing to speed things up; Illinois Extension suggests every 2 to 4 weeks, which gives the center time to heat up.
Pro tip: Keep a bag or bin of dry leaves or shredded cardboard next to the compost. Every time you add kitchen scraps, cover them with a layer of browns. It keeps the ratio right and the scraps hidden from flies and animals.
Heat, Moisture and Turning
- Over 130°F kills most pathogens
- Over 140°F destroys most weed seeds
- 160°F and above can kill the decomposers and slow the pile down
- 40 to 60% moisture, which feels like a wrung-out sponge
Heat is a sign the microbes are working. A pile that is too small, too dry or short on greens stays cold and breaks down slowly. A long-stem compost thermometer is the easiest way to see what is happening in the center.
How Long Does Composting Take?
| How you manage it | Typical time | Source |
|---|---|---|
| Turned often (every 2 to 4 weeks) | About 3 months, depending on season | Illinois Extension |
| Well-maintained pile | About 3 to 5 months | U.S. EPA |
| Left untended | Up to a year | U.S. EPA |
How to Tell When Compost Is Ready
Finished compost checklist (NC State Extension)
- You can no longer recognize the original materials
- The pile is less than 10°F warmer than the outside air
- It is dark brown or black
- It smells earthy
Sift out any sticks or eggshell pieces and return them to a new pile. Use finished compost to enrich garden beds, top-dress around plants, or blend into potting mixes for food plants like basil and potatoes. If you’re weighing compost against bagged products, see our comparison of synthetic vs. organic fertilizer.
Fix Common Compost Problems
| What you notice | Likely cause | Fix |
|---|---|---|
| Rotten or ammonia smell | Too wet or too many greens, not enough air | Mix in browns and turn the pile |
| Dry pile, nothing happening | Too dry or too many browns | Add water and greens while turning, until it feels like a wrung-out sponge |
| Pile never heats up | Too small, too dry or short on greens | Build to at least 3 feet high and across; add greens and water |
| Flies, raccoons or rodents | Exposed scraps or meat, dairy and oils in the pile | Bury scraps under browns; remove animal products |
| Tumbler leaking dark liquid | Too much food or grass, not enough browns | Add dry leaves or straw (Oregon State Extension) |
For more on composting, see our guides to compost tumblers.
Compost is just one way to feed plants from what you already have. Browse more food-growing guides in The Pantry, or see what really works in our banana peel fertilizer test of the evidence.
Frequently Asked Questions
What is the best ratio of browns to greens?
Sources differ. The EPA recommends two to three times as many browns as greens by volume, NC State Extension suggests 2 to 1, and Illinois Extension says 1 to 1. Starting near 2 to 1 and adjusting by smell and moisture works for most piles.
Why does my compost smell bad?
A rotten or ammonia smell usually means the pile is too wet, has too many greens, or isn’t getting enough air. Mix in dry browns such as leaves or shredded cardboard and turn the pile to let oxygen in.
Can I compost meat and dairy?
Not in a backyard pile. The EPA says meat, fish, bones, dairy and fats attract animals and don’t fully break down there. A bokashi system can ferment them first, according to Washington State University Extension.
How long does it take to make compost at home?
About three to five months for a well-maintained pile, according to the EPA, and up to a year if it’s left alone. Illinois Extension says turning every 2 to 4 weeks can finish it in about three months, depending on the season.
Is a compost tumbler worth it?
It keeps scraps contained and is easy to mix, but it isn’t automatically faster. An Oregon State Extension expert calls tumbler composting very slow and often finishes the material in a regular pile. Choose a large, sturdy model and add plenty of dry browns.
Can I compost in an apartment?
Yes. A worm bin with red wigglers works indoors at 59 to 77°F (NC State Extension), and a bokashi bucket ferments scraps in a sealed container before you bury them (Washington State University Extension).