FAQ Soil Moisture Sensors

The VWC values are higher/lower than I expect

  1. Make sure the sensor is installed correctly as described here
  2. Verify the numbers that you are expecting are according to the unit Volumetric Water Content (VWC) as this can cause confusion with Relative Water Content or Percent of Saturation. This can be done with a little help of our VWC calculator.

What is the difference between ECb and ECw?

In industry, EC is mostly referred to the electrical conductivity of water (ECw). However, this is not the only medium electrical conductivity can be measured in. As example, inside a substrate, it is possible to measure the EC of the soil or substrate without extracting the water. This is what we refer to as the bulk EC (ECb). The sensor only measures ECb (bulk) and together with the VWC measurement we can estimate the ECw of the water. See the article about how EC is measured. Untitled-2022-10-11-2332.png

The EC values are much lower than the level of EC in the Irrigation/Drain water

Please verify what EC values you are referring to. ECb is always lower compared to EC of the water given or drained because it will also measure the conductivity of the substrate, which in principle is 0.
ECw is an estimation of the EC values if you would extract water from the substrate. If the number of ECw is off, this can be due to a wrong calibration profile. Unfortunately, it is not easy to get to the correct ECw levels without doing an additional calibration. Please contact our support for more information about doing a custom calibration.

How can I verify that the measurements of my soil moisture sensor are accurate?

You can verify the VWC level by weighing a soil sample of a known volume. The larger part of the weight will be water. For example, a 100ml substrate sample with a VWC value of 33% will contain 33ml of water and thus will weigh at least 33 grams + plus weight of the soil. Please see our VWC calculator to quickly calculate the volume of your sample.
You can verify the ECw level, by extracting the water from your soil or by doing a dilution soil sample. Please consult the literature of your reference meter on how to execute an EC measurement on soil.

My question is not in this list:

We are happy to answer any questions regarding our soil sensors, you can open a ticket by clicking on the help button in the right lower corner or by texting your question on WhatsApp.