Get your compost ratio right the first time

Pick the materials you have, enter how much of each, and see your pile's carbon-to-nitrogen balance instantly. No guesswork. No smell.

Start mixing

Build your pile

Add materials from the list below or type your own. Enter an approximate weight in kilograms or volume in liters. The ratio updates as you type.

Quick add:

No materials added yet. Use the quick-add buttons above or type a material name to get started.

Layering guide

Once your ratio is in the green zone, use this order to stack your pile. Each layer has a job.

1

Coarse base

Twigs, small branches, or straw. 10 to 15 cm thick. This layer lets air flow in from the bottom.

2

Brown layer

Dry leaves, shredded cardboard, or straw. 10 to 15 cm. This is your carbon source. Slightly dampen it.

3

Green layer

Grass clippings, food scraps, or manure. 5 to 10 cm. This is your nitrogen source. Spread it evenly.

4

Soil sprinkle

A thin layer of garden soil or finished compost. 2 to 3 cm. This adds microbes to kickstart decomposition.

…

Repeat layers 2-4

Keep stacking brown, green, and soil until you run out of materials. End with a brown layer to keep flies away.

Water check

Your pile should feel like a wrung-out sponge. Too wet and it goes anaerobic. Too dry and microbes slow down. Add water or dry browns as needed.

Turn schedule

Turn the pile every one to two weeks for fast compost. Every three to four weeks for a slower, low-effort approach. Turning adds oxygen.

Pile size

Aim for at least one meter tall and wide. Smaller piles lose heat and break down slowly. If you do not have enough material, wait and add more before starting.

Material reference

These values are averages from university extension services. Real materials vary. Use them as a starting point.

Material	C:N ratio	Type	Notes

Common mistakes

Too much grass. Fresh grass is very nitrogen-rich. A thick layer mats down and smells. Mix it with browns or let it dry first.
Whole cardboard. Large pieces take forever to break down. Shred or soak it before adding.
Meat and dairy. These attract pests and smell bad in a home pile. Stick to plant-based scraps.
No turning. Without air, the pile goes anaerobic and produces methane. Turn it at least once a month.
Too dry. Microbes need moisture. If the pile looks dusty, water it lightly and mix.

Troubleshooting

Pile smells like ammonia: Too much nitrogen. Add dry leaves, straw, or shredded paper. Turn the pile to release the gas.
Pile smells like rotten eggs: Not enough air. Turn the pile and add coarse browns to create air pockets.
Nothing is happening: The pile may be too dry, too small, or too carbon-heavy. Check moisture, add greens, or build it up to one cubic meter.
Flies around the pile: Food scraps are exposed. Bury them in the center and cover with a brown layer.

Seasonal scenarios

Your available materials change through the year. Here is how to adjust.

Autumn leaf drop

You have a mountain of dry leaves but not many greens. Shred the leaves with a mower so they break down faster. Add grass clippings, coffee grounds, or kitchen scraps to balance the high carbon. A good mix is three parts shredded leaves to one part food scraps by volume.

Spring lawn growth

Grass comes in fast and you have more than you can use. Let it dry for a day or two before adding it to the pile. Mix one part dried grass with two parts cardboard or dry leaves. Do not add thick layers of fresh grass or it will mat and smell.

Summer kitchen scraps

Fruit and vegetable scraps pile up in warm weather. Bury them deep in the pile to avoid flies. Add browns like torn egg cartons or paper bags. Keep the pile moist but not soggy. Turn it weekly to keep it aerobic.

Winter slowdown

Cold weather slows microbial activity. Insulate the pile with straw bales or a tarp. Keep the ratio near 25:1. You may not see much change until spring, but the material will be ready to use when temperatures rise.