The humidity sensor helps distinguish between overfilling and underfilling, but does not do this automatically. One number can be deceiving. It is important to look at the shape of the graph: how quickly the humidity rises after watering, how it drops between waterings, whether there are long plateaus and sharp dips. The output must then be compared to the plant, substrate and log.
Underwatering usually appears as a rapid drop in humidity and poor response after a short watering. Overwatering often manifests differently: the graph remains high for a long time, the top layer may appear normal, and the plant looks lethargic due to problems with the roots. Therefore, the same symptom of “leaves drooping” requires different checks.
Signs of underfilling on the chart
If after watering the humidity rises briefly and then falls quickly, there may be little water or it is going past the root zone. Check the dripper, water distribution and volume. Sometimes the sensor is too far from the watering site and does not see moisture, although part of the pot is wet. Sometimes it’s the other way around: water passes through a channel along the wall and does not saturate the substrate.
If you are underfilling, it is useful to weigh the pot or carefully check the depth of the wet layer. If the plot is dry, the pot is light, the leaves lose turgor in hot hours, and quickly recover after watering, underwatering is likely. But don't increase the volume suddenly. It is better to add the dose gradually and watch the reaction.
Signs of overflow
Overflow is not always visible as "very wet". The substrate can hold moisture deep, and the top layer dries out. At the same time, the graph does not return to normal levels for a long time. If watering is frequent, there are few pauses, and the plant is lethargic even with high humidity, it is worth checking the roots, drainage and ventilation.
Another sign is weak dynamics. After watering, the value hardly changes, because the sensor is already in a waterlogged area. In this case, automation may consider that everything is stable, although the root zone suffers. The watering log helps you see how much water was actually applied.
When it's not watering that's to blame
Dullness and stains are not always due to water. Overheating, cold window sill, root damage, pests, harsh fertilizing and low light can all look similar. Therefore, the output from the sensor must be careful. If the schedule is normal, but the plant is deteriorating, open your diary: what has changed in recent days?
Compare soil moisture with temperature, light and ventilation. After turning on the hood, the substrate can dry faster. During a cloudy week, the plant consumes less water. The analysis of such connections is described in the article history of microclimate and graphics.
How to set up an advisor
The GrowerHub advisor must take into account not only the current sensor value, but also the trend, how old the data is, the last action and the stage of growth. The recommendation to “water” is safe only if the sensor is fresh, the zone is known, there are no signs of overflow and the limits are not exceeded. If there is little data, it is better to give a hint for checking rather than turning on the pump.
The logic of the recommendations is discussed in more detail in the article how the advisor makes decisions about watering. Transparency is important for the user: why the system believes that this is underfilling, and what data influenced the conclusion.
Conclusion
Overfilling and underfilling are distinguished by more than one percentage of humidity. See the dynamics of the schedule, the volume of watering, the appearance of the plant and events in the diary. The sensor gives the signal, the log gives the reason, and inspection confirms the conclusion. Only together do they make the diagnosis reliable.