Teros 12 VWC & pwEC calculations for rockwool

Looking for any insight or direction to publicly available calibration equations for teros 12 sensors.

Currently using their “stock mineral soil” equation, but am looking for more insight if anyone has custom ones.

According to METER tests, a single calibration equation will generally suffice for most mineral soil types with ECs from 0 to 8 dS/m saturation extract. VWC (Θ) is given by Equation 6:

VWC [Θ] (m3 / m3)= 3.879×10−4 × RAW −0.6956

A linear equation is used for the mineral soil calibration because it provides the best predictions of VWC in the range of VWC found in mineral soils, but this equation reaches a maximum at approximately 0.70 m3/m3 in pure water. To display data on a scale from 0 to 1.0 m3/m3, VWC should be modeled with a quadratic equation (which would result in a 1.0 m3/m3 in water). However, METER does not recommend this for mineral soils because it often makes the calibration in the range of VWC found in mineral soil less accurate.

@Medicine.grower can probably help you out. Unsure if he’s around on the weekend. Pretty sure he’s been on that sensor for while.

Thanks. Adding that I am using grodan hugo blocks. I’ve combed through research papers and other sources online but cannot find shared calibration equations for different media types other than the stock ones.

With the stock equations my VWC rarely goes above 42% even when completely saturated. Where I would expect it to be closer to 60-70% based off its saturation. If no one can point me in the right direction I will attempt a custom calibration using meter groups calibration guide. Calibration Teros 12

This is the soilless calibration, I think this is what your looking for.

Thanks Medicine.grower! I also renewed my online search and finally found this just now… page 70 Calibration Curves online has a couple more calibration curves for various medias. Are you using meters zentra cloud?

Yes I’m using the teros 12 with the zl6 data logger, I’m looking into agrowtek platform since there’s no subscription charge and each module handles 8 sensors and they are 250$.

No shit, you’ve heard good things about the Agrowtek sensors compared to the t12?

It’s just their data logger that accepts teros 12 sensors. Seems like there’s a bunch of people trying to do this now.

any logger that comunicates with sdi-12 protocol will read any sdi-12 sensor.

Where did you find this?


This should help It’s another calibration for Rockwall like the one you have a soil