This moisture sensor is ideal for monitoring the dampness of soil, for example in houseplants or window boxes. With strategic planning the sensor can work in outdoor situations, as long as Knut is safely sheltered from the elements and still within range of Wi-Fi.

Specs for the moisture sensor

  • Units: Centibars (cb)
  • Range: 0 cb to 200 cb
  • Recording triggered by: user-defined recording intervals
  • Safe for use in: Soil, dirt, clay, fertilizer (This sensor is less accurate when used in coarse soil like sand or potting soil. See considerations below.)

Considerations when using the moisture sensor

In order to accurately reflect the moisture in the soil, the moisture sensor should be tightly packed in the soil. The Moisture Sensor works well in most soils, but does not work as well in extremely coarse soils like sand or potting soil. In these looser soils, the moisture exchange between soil and sensor is reduced and the sensor may be slow to detect changes in actual soil moisture.

Because moisture is measured in centibars, small numbers indicate high moisture and large numbers indicate low moisture. When you customize Knut’s alert settings, you may want to consider the language choice carefully. For example, we find it least confusing to make a rule like:

if moisture is more than 30 centibars then send low alert

That way the alert would indicate to us that the moisture is low, even though the value of centibars is above our threshold.