Global Araç
Compost Ratio Calculator
- Grass clippings (fresh)
- Fruit & vegetable scraps
- Coffee grounds & filters
- Tea bags
- Eggshells (crushed)
- Fresh garden trimmings
- Manure (herbivore only)
- Seaweed
- Dry fall leaves
- Shredded cardboard
- Straw & hay
- Sawdust (untreated)
- Pine needles
- Wood chips
- Shredded newspaper
- Dryer lint (natural fibers)
- Meat, fish, bones
- Dairy products
- Oils & fats
- Diseased plants
- Pet waste (dog/cat)
- Treated wood or sawdust
- Coal/charcoal ash
- Weeds with mature seeds
Compost piles fail for one of two reasons: too much “green” nitrogen-rich material (food scraps, fresh grass, coffee grounds) without enough “brown” carbon-rich material (dry leaves, straw, shredded paper, cardboard), or vice versa. The microbial decomposition process needs a target carbon-to-nitrogen ratio of 25-30 parts carbon per 1 part nitrogen by weight for optimal hot composting. By volume, this translates to roughly 3 parts brown to 1 part green (browns are less dense per gram of carbon than greens are per gram of nitrogen). Get the ratio wrong and the pile either turns into anaerobic stinking mush (too much green) or sits inert as a dry collection of leaves (too much brown, not enough nitrogen for microbes).
The calculator takes your green and brown volumes (estimates by buckets, cubic feet, or rough proportions) and outputs current ratio plus “health tier” (too green / balanced / too brown), with specific suggestions for what to add to rebalance. Common mistakes the calculator surfaces: (1) Kitchen-scrap-only piles — food waste alone is overwhelmingly green, piles smell, attract rodents. Add 3x as much shredded paper or dry leaves. (2) Fall-leaf piles dumped without greens — dry leaves alone don't decompose for 12+ months. Add coffee grounds, manure, or fresh grass to activate. (3) Grass-clipping piles — fresh grass alone goes anaerobic fast (slimy green mass that smells like ammonia). Mix with browns immediately.
Practical tips beyond the ratio: (1) Particle size matters — smaller pieces decompose faster. Shredded leaves beat whole leaves; cut food scraps to 1-2 inch pieces. (2) Moisture target: like a wrung-out sponge — feel of the pile should be damp not wet. Too wet → add dry browns; too dry → spray water. (3) Aeration — turning weekly accelerates by 2-3×. Or design for passive aeration with a loosely-stacked pile. (4) Critical mass — piles under 27 cubic feet (3x3x3 ft) often don't generate enough heat for “ hot” composting (140°F internal — kills weed seeds and pathogens). Smaller piles still work but slower at lower temperatures. (5) C:N ratios of common inputs: coffee grounds 20:1, manure 15:1, fresh grass 15:1, kitchen scraps 25:1, dry leaves 60:1, straw 75:1, cardboard 350:1, sawdust 500:1. Mix browns and greens to hit roughly 25-30:1 average.
Nasıl Kullanılır
- Estimate your current pile's green volume (food scraps, fresh grass, coffee grounds).
- Estimate brown volume (dry leaves, straw, shredded paper, cardboard).
- Read current ratio and health tier (too green / balanced / too brown).
- Read suggested adjustments — add browns or greens to rebalance.
- Re-check after a week of new additions and turning.
Ne Zaman Kullanılır
- Diagnosing a smelly compost pile (typically too much green).
- Diagnosing a stalled / inactive pile (typically too much brown or too dry).
- Planning fall leaf disposal — pairing with kitchen scraps for active winter pile.
- Onboarding new composters who don't yet have intuition for the ratio.
- Comparing your pile's composition against ideal target.
Ne Zaman Kullanılmaz
- Vermicomposting (worm bins) — different ratio rules; worms prefer slightly higher green percentage with shredded paper bedding.
- Bokashi systems — anaerobic, different chemistry, no green/brown ratio applies.
- Industrial / commercial composting — different scale, mechanical turning, different rules entirely.
- Mulch-only application — mulch isn't actively decomposing the same way.
Yaygın Kullanım Senaryoları
- Educational use — demonstrating the underlying concept
- Onboarding a colleague who needs the same calculation/conversion
- Verifying a number or output before passing it on
- Quick calculation during a typical workday
Sık Sorulan Sorular
What's green vs brown?
GREENS: nitrogen-rich materials, typically wet/fresh. Includes: kitchen vegetable scraps, fruit peels, coffee grounds, tea bags, fresh grass clippings, eggshells (technically C+N), animal manure (NOT cat/dog/human), fresh garden trimmings. BROWNS: carbon-rich, typically dry. Includes: dry leaves, straw, hay, shredded newspaper, cardboard, sawdust, wood chips, dried plant stalks, paper towels (uncolored), brown paper bags. The names refer to nitrogen content not actual color — coffee grounds are brown-colored but are GREENS due to nitrogen content.
Why is my pile smelly?
Almost always: too much green (nitrogen) plus excess moisture causing anaerobic conditions. Anaerobic decomposition produces hydrogen sulfide (rotten egg smell) and ammonia (urine smell). Fix: add 2-3× more browns (shredded leaves, paper, cardboard) and turn to introduce oxygen. The pile should smell earthy when working correctly — like forest floor. Smelly = ratio problem; turn and add browns.
Why isn't my pile heating up?
Common causes: (1) Too small (under 27 cubic feet doesn't retain enough heat). (2) Too dry — microbes need moisture; spray water. (3) Too brown — not enough nitrogen for microbial activity; add coffee grounds, manure, or fresh grass. (4) Compacted — needs aeration; turn the pile. (5) Cold weather — winter slows everything; this is normal. Pile heats from microbial respiration; heat = active decomposition. Hot composting reaches 140°F internal; warm composting 100-130°F; cold composting (no heat) still decomposes but slowly.
How long does compost take?
Hot composting (perfect ratio + frequent turning + critical mass): 4-8 weeks to finished compost. Warm composting (decent ratio, occasional turning): 3-6 months. Cold composting (just pile and wait): 6-18 months. Most home gardeners use the “continuous pile” method — add new material on top while old material at the bottom finishes — and pull finished compost from the bottom every 4-8 months.
Can I add too much of one thing?
Yes. Solving green-overload: dump several bags of dry leaves on top, mix in. Solving brown-overload: pour coffee grounds (Starbucks gives away their grounds for free), add fresh grass clippings, even add a small amount of finished compost as “starter.” Particularly bad inputs in excess: citrus peels (acidic, slow to break down), pine needles (acidic, slow, mat together), and meat/bones (attract pests). Use these sparingly or skip entirely.
When is compost finished?
Looks dark and crumbly like rich soil. No identifiable original materials (no recognizable banana peels, eggshells, or leaves). Earthy smell, not putrid. Cool to the touch (decomposition complete). Roughly 30% of original input volume. Sift through 1/2-inch hardware cloth to remove unfinished chunks (return chunks to active pile). Use finished compost as soil amendment, mulch, or top-dressing for garden beds.