The time-and-temperature rule names five turnings for a windrow held at 55 °C for fifteen days. Operators commonly turn twice, and the reason is that the rule is written for the worst case.
The rule says five turnings; practice says two
window CURING SEASONwritten 2026-08-03rots yes — these figures moveresponsible Windrow Field Manual (a named masthead, not a person)
[['The regulation', 'Five, spaced across fifteen days', 'The worst feedstock, the coldest climate'], ['Typical practice', 'Two, when the temperature drops', 'A well-mixed pile in a mild season'], ["The manual's reading", 'Turn on temperature, log the count', 'The rule wants every particle in the hot zone']]
| p | r | o | b | e | c | a | r | d | : | t | h | e | r | u | l | e | a | n | d | t | h | e | p | r | a | c | t | i | c | e | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| P | o | s | i | t | i | o | n | |||||||||||||||||||||||||||||
| T | u | r | n | i | n | g | s | |||||||||||||||||||||||||||||
| W | h | a | t | i | t | a | s | s | u | m | e | s |
What the rule is actually trying to guarantee
The rule exists so that every part of the material spends time above the temperature at which pathogens die. Turning is how the outside of the pile gets to the inside. Five turnings is the count that makes the guarantee hold for a pile that is not well mixed and for weather that does not help.
| Pile condition | Turnings needed in practice | Why fewer can work |
|---|---|---|
| Well mixed, mild weather, good structure | Two or three | The pile is already near-homogeneous |
| Layered, cold weather, coarse structure | Four or five | The outside has to be cycled in deliberately |
| Wet, dense, poorly structured | More than five | Anaerobic pockets persist regardless |
Why the manual will not simply endorse turning twice
The manual holds that the right trigger is temperature, not the calendar, and that the log is what makes either position defensible. A pile turned twice with a temperature series that shows every part of it above 55 °C for fifteen days is a better record than a pile turned five times with no log at all. The regulation asks for the record, and the record is the deliverable.
This is a position some operators will disagree with, and the disagreement is fair: a rule is a rule, and a regulator is entitled to read the count literally. The manual's point is that the count exists to serve the outcome, and the outcome is measurable.
What to log
- Date and time of every turning.
- Core temperature before and after each turning.
- The number of probe positions per check, and where they were.
- The date the pile first reached the holding temperature, and the date it was last above it.
Where the numbers come from
- S1Troubleshooting, Municipal Yard Waste Composting Operator's Fact Sheets, Cornell Universitysupports the troubleshooting response when a pile is not holding temperature
- S2Odor Management, Cornell Composting, Cornell Universitysupports the odour-management context that pushes operators to turn
- S3Advances in controlling composting odor: a review of the last decade, Journal of Engineering and Applied Sciencesupports the odour research that frames how often a pile is turned
- S4Types of Composting and Understanding the Process, U.S. Environmental Protection Agencysupports the process description the turning count is applied to
One link, one document. No home pages, no search results, no bare domains.
Put this page down Put this page down when you have decided what your log will record. The log is the part an inspector reads.