Observation log
Pronounced / ob·zer·VAY·shun log /
A dated record of what you noticed and what you changed.
Example in a sentence
“Checking her observation log showed the leaf curl started two days after raising light intensity.”
Keep the two apart
Write observations first: a leaf changed colour, a reading was recorded or a tray remained wet. Put your interpretation in a separate sentence. That makes it easier to revisit an earlier assumption.
A simple entry
Use a date, plant or sample identifier, observation, action and follow-up. Include units with measurements. A useful log does not need to be long; it needs to be clear enough that you can compare entries later.