A windrow is one long row of material left in the open to dry, cure, or melt. It is defined by its cross-section, not its length, and every decision it forces is about moisture or placement.
Windrow: one long row left out to dry, cure or melt
window ALL WINDOWSchecked 2026-09-16responsible Windrow Field Manual (a named masthead, not a person)
[['Cut hay', 'Moisture %, top and bottom of the row', 'Below the baling band for the bale size you own'], ['Pushed snow', 'Distance from culvert mouth, metres', 'Far enough that meltwater reaches the inlet, not the road'], ['Compost', 'Core temperature, °C, for the days the rule names', 'Inside the pathogen window, not just hot once']]
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One word, three materials, three different questions
A windrow is a row. That is the whole of the definition, and it is why the word turns up in three trades that otherwise share nothing. What the row is made of decides what you measure: moisture if it is forage, distance if it is snow, temperature if it is compost.
| Material | Row shape in practice | What the row is for | The measurement it turns on |
|---|---|---|---|
| Cut hay | Trapezoid, 1.0–2.0 m wide, sitting on stubble | Curing: losing water without losing leaf | Moisture content, % wet basis |
| Pushed snow | Long ridge at the shoulder, 1.5–3 m high | Storage until melt, and keeping the road clear | Distance from the inlet, in metres |
| Compost | Trapezoid, 2.5–4.5 m wide, 1.2–2.1 m high | Curing to a pathogen standard | Core temperature, °C, held for a set number of days |
Why the cross-section matters more than the length
Length is cheap. A row can be as long as the field or the shoulder, and nothing in the drying, melting or curing arithmetic depends on it. Width and height set the surface-to-volume ratio, and that ratio sets how fast the middle of the row changes. A row that is too wide for its height keeps a wet core; a row that is too tall for its width sheds water badly and packs down. This is the same argument in all three materials, which is the only reason one manual can hold them.
A row 1.2 m wide and 0.6 m high has roughly 1.6 m² of surface for every metre of length. Widen it to 1.8 m and the same metre of length gains mass faster than it gains surface. That is the trade, and it is arithmetic, not opinion.
Boundary: what a windrow is not
The trade press uses windrow, swath and row almost interchangeably, and the substitution changes the answer. These are not the same thing and the manual does not treat them as such.
| Term | What it actually is | Why the confusion costs you |
|---|---|---|
| Windrow | A row of material placed deliberately, in the open, to dry, cure or melt | The default word, so everything gets called this |
| Swath | The row a mower leaves, before any raking or tedding | Swath width sets drying speed; a windrow's width sets core moisture |
| Merge | Two or more swaths combined into one row for the baler | A merge raises the row's mass without raising its surface |
If a page tells you to check the windrow moisture when what you have is an unraked swath, the number it gives you is for the wrong object. Near kin, different measurement.
Where this manual will argue with a bulletin
Several extension bulletins print a single windrow width as if it were a rule. It is not; it is a starting point for a particular baler and a particular crop. A 1.5 m row in a heavy first-cut grass stands up and dries differently from a 1.5 m row in a thin alfalfa stand, and the bulletins that print one number are describing the case they tested. The manual disagrees with the single-number habit, and says so here rather than in a footnote.
Where the numbers come from
- S1Haymaking (Chapter II), Hay and Straw Conservation, FAO Agricultural Services Bulletin 154supports the drying sequence a cut row goes through before baling
- S2Building Windrows, Municipal Yard Waste Composting Operator's Fact Sheets, Cornell Universitysupports the windrow cross-section dimensions used for a curing row
- S3Introduction (Chapter I), Hay and Straw Conservation, FAO Agricultural Services Bulletin 154supports the boundary between a mown swath and a deliberately placed row
One link, one document. No home pages, no search results, no bare domains.
Put this page down Put this page down when you can say which of the three materials you are standing in front of. The width and the measurement follow from that.