Every diary entry carries five facts. What: the sign in plain words, with a photo and a coin for scale. Where: room, rack, shelf height, bag numbers, distance from door and air inlet. How many: a count, not "some", repeated 48 hours later. Since when: the date and the crop day, meaning days after spawning or casing. What changed: watering, a power cut, a new casing lot, a visitor, in the previous three days.
The five facts do half the diagnosis. Trouble only near the inlet points at air. Trouble in every bag from one compost batch points at compost. Trouble the day after a power cut points at temperature.