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If a sensor’s moisture percentage doesn’t match what you see in the soil, work through the checks below. Most accuracy problems come from probe placement or a calibration that no longer matches the soil.

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Readings look too low (always near 0%)

  • Push the probe deeper so the moisture contacts are fully covered — exposed contacts read as dry air.
  • Confirm the soil isn’t pulling away from the probe after drying out. Press the soil back around the probe.
  • Re-run the wet point in Calibrate a sensor after watering.

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Readings look too high (always near 100%)

  • Make sure the probe isn’t sitting in a pocket of standing water at the bottom of the pot.
  • Check drainage — a pot without drainage holes stays saturated and reports high indefinitely.
  • Re-run the dry point in Calibrate a sensor with the probe clean and dry.

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Readings are stuck or not updating

  • Confirm the sensor is still reporting on the soil moisture dashboard — a stale timestamp points to a connectivity issue, not accuracy.
  • Verify the sensor is well matched to the pot size. See Sensor types for probe-length guidance.
Still off after recalibrating? The probe contacts may be corroded. Wipe them with a dry cloth, and replace the sensor if a thin film remains.

Calibrate a sensor

Reset the dry and wet reference points.

Sensor types

Match the probe length to your pot.