Build the row at the width your turner can reach, at a height that holds heat without going anaerobic, from a mix that starts near 30 to 1 carbon to nitrogen and 55% moisture.
How to build a compost windrow
window CURING SEASONchecked 2026-09-16responsible Windrow Field Manual (a named masthead, not a person)
What you need Carbon feedstock (leaves, straw, woodchip), nitrogen feedstock (grass, manure, food waste), water, a turner or a loader, a thermometer with a 1 m stem, a log sheet.
[['Carbon to nitrogen', 'About 30 to 1 by weight', 'Recipe, then the smell after three days'], ['Moisture', '50–60% by weight', 'Squeeze test: one or two drops from a handful'], ['Width', '2.5–4.5 m', 'Set by the turner, not by the pile'], ['Height', '1.2–2.1 m', 'Below 1.2 m it cannot hold heat in winter'], ['Structure', 'Woodchip or coarse material throughout', 'The pile should not slump when turned']]
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Steps
- Lay a coarse base of woodchip or straw so air can enter from below and water can drain away.
- Build in layers: a carbon layer, then a nitrogen layer, then water, then repeat. Layering beats mixing, because the turner will mix it later.
- Test the moisture by squeezing a handful. One or two drops means you are in the band; a stream means too wet; nothing means too dry.
- Shape the row to the width your turner can straddle and the height that holds heat. A row that is too tall for its width will go anaerobic in the core.
- Insert the thermometer to the core and log the temperature daily. The first reading that matters is the one three days after the build.
The two failures in week one
| Symptom | Cause | Fix |
|---|---|---|
| Pile never heats above 40 °C | Too dry, or too little nitrogen, or too small | Water it, add nitrogen, rebuild taller |
| Pile smells sour within 48 hours | Anaerobic core, usually from over-watering | Turn it immediately and add coarse structure |
| Temperature spikes then collapses | The pile has dried out on the surface | Water and turn; expect to repeat |
| Temperature holds but the outer layer stays cold | Not enough turnings to bring it inside | Increase the turn count against the rule |
The manual's position on recipe calculators
A carbon-to-nitrogen calculator is a starting estimate, not a recipe. The feedstocks you actually have vary by batch, so the first pile is a calibration run: build it, measure it, and adjust the next one. The manual holds that one measured pile teaches more than ten calculated ones.
Where the numbers come from
- S1Water, Municipal Yard Waste Composting Operator's Fact Sheets, Cornell Universitysupports the moisture band and the squeeze test used at the build
- S2The Compost Process, Municipal Yard Waste Composting Operator's Fact Sheets, Cornell Universitysupports the process stages a new windrow passes through
- S340 CFR 503.32 — Pathogens, U.S. Code of Federal Regulationssupports the pathogen reduction requirement the build has to allow for
- S4Approaches to Composting, U.S. Environmental Protection Agencysupports the composting approach the build method follows
One link, one document. No home pages, no search results, no bare domains.
Put this page down Put this page down when the row is built and the first temperature is logged. The log is what the rule asks for.