Good compost is a balance of nitrogen-rich greens and carbon-rich browns. Too many greens make a wet, smelly pile and too many browns make a pile that barely heats. This compost recipe builder tells you the ratio of browns to greens in your pile and what to add to fix it. Enter the volume of each material you have, in gallons or buckets, and use the same unit for everything.
Enter how much of each material you have, in gallons or buckets, using the same unit for all.
Greens (nitrogen)
Browns (carbon)
How to use the compost recipe builder
- Enter the amounts of kitchen scraps, grass clippings, coffee grounds and fresh manure you have as greens.
- Enter the amounts of dry leaves, straw, cardboard and wood chips as browns.
- Press the button to see your ratio and advice on adding more greens or browns.
Greens and browns
Greens are fresh, moist and rich in nitrogen: vegetable and fruit scraps, fresh grass clippings, coffee grounds and fresh manure from plant-eating animals. Browns are dry and carbon-rich: dry leaves, straw, shredded paper and cardboard, and wood chips. A pile of 2 to 3 parts browns to 1 part greens by volume composts well for most home gardeners. This is a rule of thumb, because by weight the proportions are different, since browns are light and fluffy.
Troubleshooting your compost
- Smells like ammonia or rot: too many greens or too wet. Mix in browns and turn the pile.
- Slow, cool, not breaking down: too many browns or too dry. Add greens and water until damp like a wrung-out sponge.
- Attracts flies or animals: bury food scraps in the middle, and avoid meat, dairy, oils and pet waste.
- Weed seeds or diseased plants: only compost them in a hot pile, which reaches around 130 to 160 degrees F and is turned often.
How long does compost take?
A well-built, turned hot pile can finish in a few months. A cold pile you leave alone may take a year or more. The finished product is dark, crumbly and smells like earth. To plan the size of your bin, use the compost bin size calculator, and for fall leaves see the leaf mulch calculator.
Frequently asked questions
Can I compost citrus peels and onions?
Yes, in moderation. Large amounts can slow worms and microbes, so mix them with other materials.
Are coffee grounds greens or browns?
Coffee grounds act as greens because they are rich in nitrogen, even though they look brown.
Is it safe to use compost on vegetables?
Yes, once it is fully finished and cooled. Do not use fresh manure on crops you will eat within a few months, and keep pet waste out of compost.