Turning kitchen scraps into dark, soil-like compost requires layering greens with browns in a 1:2 or 1:3 ratio and keeping the pile as damp as a wrung-out sponge.
Home composting transforms fruit peels, coffee grounds, and eggshells into free garden gold while keeping waste out of the landfill. The method is simpler than most people think: collect your food scraps, mix them with dry leaves or cardboard, add water and air, and let nature do the work. Below is the step‑by‑step process used by the EPA and USDA that works in any U.S. backyard.
What You Can and Cannot Compost
Start by knowing which kitchen leftovers belong in the pile. Compostable items are called “greens” (nitrogen‑rich, often moist) and “browns” (carbon‑rich, dry). You need both for the pile to break down properly.
Greens (kitchen scraps and fresh plant material):
- Fruit and vegetable scraps, including peels, cores, and trimmings
- Coffee grounds and paper filters
- Tea bags without staples
- Crushed eggshells
- Garden clippings and fresh grass
Browns (dry, carbon‑rich material):
- Dry leaves, straw, or hay
- Shredded cardboard and paper (black‑and‑white newspaper only)
- Small twigs and wood chips
- Uncoated paper and paper towels
Keep out: meat, bones, dairy, oily or greasy foods, and any inorganic materials. These attract pests, create odors, and slow the process.
Wondering which composting tool fits your space? Our tested roundup of the top food scrap recyclers covers countertop electric units and outdoor bins that speed up the job.
The Right Ratio of Greens to Browns
The EPA and USDA both recommend 2 to 3 parts browns for every 1 part greens, measured by volume. That means if you add a bucket of kitchen scraps, follow it with two or three buckets of dry leaves or shredded cardboard. This ratio keeps the pile from getting soggy and smelly, and it gives microorganisms the carbon they need to break down nitrogen‑rich food waste efficiently. If you notice an ammonia smell or the pile gets slimy, add more browns.
How to Build and Maintain Your Compost Pile
The official EPA method uses a “lasagna” layering approach. Here are the steps to set it up and keep it running:
- Choose a spot. Pick a dry area with good drainage and easy access to water. A spot in sun or partial shade works fine. The USDA suggests a simple bin made from wire mesh and three or four poles if you want to contain the pile.
- Collect greens. Store kitchen scraps in a closed container under the sink or in the fridge to avoid fruit flies.
- Start with a base. Lay down a 4- to 6-inch layer of bulky browns such as twigs and wood chips. This lets air flow underneath.
- Layer like lasagna. Alternate greens and browns in thin layers, always covering food scraps with 4 to 8 inches of dry leaves or other browns. This prevents odors and keeps pests out.
- Keep it moist. Aim for the moisture level of a wrung-out sponge. Add water if it’s too dry; add more browns if it’s too wet.
- Turn it monthly. The USDA recommends turning the pile about once a month to add oxygen.
- Watch for clues. The pile will heat up in the first few days. When it stops heating and you can no longer see recognizable food scraps, it’s ready for the curing stage.
After the pile stops heating, let it cure for at least 4 weeks before using the compost in your garden. During this time the microorganisms finish stabilizing the nutrients. Finished compost smells earthy and looks dark, crumbly, and uniform.
| Common Mistake | How to Fix It |
|---|---|
| Bad smell (rotten eggs) | Too wet or not enough browns. Add dry leaves or shredded cardboard and turn the pile. |
| Ammonia smell | Too many greens. Add browns to balance the ratio. |
| Pile is dry and not breaking down | Add water until moisture matches a wrung-out sponge. Include more moist greens. |
| Pests in the pile | Food scraps are exposed. Always cover with 4 to 8 inches of browns. |
| Pile is cold after two weeks | Not enough oxygen. Turn the pile to aerate it. |
| Very slow decomposition | Scraps are too large. Chop tougher pieces before adding, and turn the pile monthly. |
FAQs
Can I compost citrus peels and onion scraps?
Yes. Citrus peels and onion scraps break down like other fruit and vegetable waste. They are fine to include, though citrus takes slightly longer to decompose. Worms may avoid them, but the backyard pile handles them without issue.
Can I compost in winter if the pile freezes?
Yes. The pile will slow down or go dormant in freezing temperatures, but it restarts when it thaws. Keep adding greens and browns throughout winter; cover with a tarp to block excess snow, and turn again in early spring.
What do I do with finished compost?
Mix it into garden soil at planting time, spread it as a topdressing on lawns, or use it as mulch around trees and shrubs. Finished compost is a soil amendment, not a fertilizer — it improves soil structure and supports plant health without burning roots.
References & Sources
- U.S. EPA. Composting at Home Official home‑composting guidance with lasagna layering method and material lists.
- USDA NRCS. Composting in Your Backyard Supplemental guidance on bin construction and monthly turning.
- USDA People’s Garden. What to Compost List of compostable materials and best practices for backyard systems.