apply-composting-method

Apply Composting Method

Set up and manage a home compost system using correct carbon-to-nitrogen ratios, moisture levels, and turning frequency to produce finished compost in 8–12 weeks from kitchen scraps and garden waste.

Why This Is Best Practice

Adopted by: The USDA NRCS (Natural Resources Conservation Service) promotes composting as the primary organic matter recycling method in residential and small-farm contexts. The RHS, Rodale Institute, and all organic gardening organizations teach composting as foundational to soil health. Home composting diverts 30% of household waste from landfill (EPA estimate) and produces a soil amendment worth $5–$15 per cubic foot if purchased commercially. Impact: Lowenfels (2010) documents the soil food web — compost is not merely fertilizer; it is the inoculant for an active biological community (bacteria, fungi, protozoa, nematodes) that feeds plants and suppresses pathogens. A garden with regular compost inputs builds soil organic matter over time, reducing water needs by 20–30% (improved water retention), reducing fertilizer needs, and improving disease resistance. Landfilled food waste produces methane; composted food waste produces carbon.

Steps

1. Select the composting system

Hot composting (recommended for fastest results):

• Minimum pile volume: 1 cubic yard (3' × 3' × 3') — below this mass, the pile loses heat too quickly
• Reaches 130–160°F (55–70°C) — kills weed seeds and pathogens
• Active management: turn every 3–5 days during active phase; finished in 6–12 weeks
• Best for: large volumes; garden and kitchen waste together

Cold composting (low-effort, slower):

• Pile or bin without turning; pile grows over time
• Does not reach temperatures to kill weed seeds
• Finished in 6–12 months
• Best for: low-volume, intermittent kitchen scraps; minimal effort preference

Worm composting (vermicomposting):

• Red wigglers (Eisenia fetida) process kitchen scraps in a contained bin
• Suitable for apartment or indoor use; small volume
• Produces vermicast — extremely high-nutrient, biologically active amendment
• Not suitable for meat, dairy, or large volumes

Tumbler composters:

• Enclosed rotating drum; keeps pests out; tidy appearance
• Turns easily; lower volume than open pile
• Can heat if properly loaded; suitable for suburban use

2. Balance the carbon-to-nitrogen ratio (C:N)

The most important composting variable:

• Target C:N ratio: 25:1 to 30:1 — this feeds the bacteria optimally
• Greens (nitrogen-rich, C:N 10:1–20:1): kitchen scraps (fruit, vegetables, coffee grounds), fresh grass clippings, fresh plant trimmings, manure
• Browns (carbon-rich, C:N 50:1–500:1): dry leaves, straw, cardboard (torn), newspaper, wood chips, dried stems

Practical ratio: ~3 parts browns to 1 part greens by volume.

Signs of imbalance:

• Pile smells like ammonia → too much nitrogen (green); add more browns
• Pile is cold and not decomposing → too much carbon (brown); add more greens or nitrogen source
• Pile is slimy and wet → too many greens + too wet; add dry browns and turn

3. Manage moisture

Target moisture: damp as a wrung-out sponge — squeeze a handful; a few drops of water should appear; the pile should not pour water when squeezed.

• Too dry: microbes slow or stop; pile doesn't heat; add water when turning; cover with cardboard to retain moisture
• Too wet: anaerobic conditions; pile smells rotten; add dry browns; turn to aerate

In rainy climates: cover the pile; prevent waterlogging. In dry climates: water the pile during turning.

4. Aerate the pile — turning schedule

Oxygen drives aerobic decomposition (no smell); lack of oxygen produces anaerobic decomposition (sulfur/rotten smell):

• Hot composting: turn every 3–5 days during the active phase; move outside material to the center; brings oxygen in and moves undecomposed material to the hottest zone
• Cold composting: turn monthly (minimal intervention)
• Sign to turn: pile temperature dropping from 130°F+ down toward ambient; this means the active front has consumed available material; turning restarts the thermophilic phase

Tools: a compost fork or dedicated turning tool; a compost thermometer (recommended for hot composting)

5. Recognize finished compost

Ready indicators:

• Color: dark brown to black (original materials no longer identifiable)
• Smell: earthy, forest-floor smell (not chemical, not rotten)
• Temperature: pile no longer heating, even after turning
• Texture: crumbly, loose, no identifiable original materials except woody stems

Timeline:

• Hot composting (proper C:N, turning every 3–5 days): 6–12 weeks
• Cold composting (no turning): 6–12 months
• Vermicomposting: 3–6 months depending on feeding rate

Unfinished compost applied to plants can harm them (still actively decomposing, drawing nitrogen from the soil). Cure finished compost for 2–4 weeks before application if in doubt.

6. Apply finished compost correctly

Application rates:

• Raised beds: top-dress 2–3 inches each spring; no tilling (no-till preserves biology)
• Lawn: ¼ inch application as top-dress in spring and fall; rake to work between grass blades
• Potting mix: 20–30% by volume in potting mixes; not more (compost-only is too rich and can burn roots in high concentration)

What to compost:

• YES: fruit and vegetable scraps, coffee grounds and filters, tea bags, eggshells, bread (in moderation), grass clippings, leaves, plant trimmings, hair, paper and cardboard
• NO: meat, fish, dairy (attract rodents; slow to decompose without hot composting), diseased plants (may survive if not hot composted), pet waste (pathogens), oils and fats

Common Mistakes

• Pile too small to heat up: under 1 cubic yard, the pile lacks enough mass to retain heat. Build the pile to critical mass before actively managing it.
• Too many kitchen scraps, not enough browns: kitchen waste is high-nitrogen; without an equivalent volume of dry carbon material, the pile becomes a smelly anaerobic mass. Always have a bin of dry leaves or cardboard available to layer with kitchen scraps.
• Applying unfinished compost: half-composted material actively decomposes in the soil, temporarily binding nitrogen away from plants (nitrogen immobilization). Wait for the earthy smell and uniform dark texture before applying.

When NOT to Use

• Large-scale agricultural composting: farm-scale compost operations require windrow turner equipment, temperature monitoring programs, and regulatory compliance not covered by home composting methods.