Decagon 5TM Soil Moisture and Temperature Sensor

Temperature Integrated with Soil Moisture

The 5TM delivers temperature, measured by an onboard thermistor, along with accurate volumetric water content.

Engineered for Accuracy

The 5TM determines volumetric water content (VWC) by measuring the dielectric constant of the soil (or other media) using capacitance/frequency domain technology. Signal filtering minimizes salinity and textural effects, making the 5TM accurate in most soils and soilless media. Factory calibrations are included for mineral soils, potting soils, rockwool and perlite.

Easy Installation

The 5TM's small size makes it easy to install in the field and the greenhouse. This robust sensor can be pushed directly into undisturbed soil to ensure good accuracy.

Plug and Read

Get straight to the data with an Em50-series data logger. Just install the 5TM, plug it into the Em50, set the clock and measurement intervals and start logging data. No programming required.

Reasons to pick the 5TM:

If you want to measure volumetric water content AND

  • Are interested in mechanisms that are affected by temperature.
  • Want to use SDI-12
  • Anticipate temperature change in your soil (or soil-less media)
  • Don't want to be one of those researchers saying, "I wish I had temperature data with this..."

Easy Integration

The 5TM comes standard with both serial and SDI-12 communication options, meaning easy integration with systems manufactured by other companies.

Accuracy Apparent dielectric permittivity (E a): ± E a (unitless) from 1-40 (soil range), ±15% from 40-80
VWC: Using Topp equation: ±0.03m3/m3 (±3% VWC) typical in mineral soils that have solution electrical conductivity <10dS/m
Using medium specific calibration, ±0.01 - 0.02m3/m3 (±1-2% VWC) in any porous medium
Temperature: ±1°C
Resolution Ea: 0.1Ea (unitless) from 1-20, <0.75Ea (unitless) from 20-80
VWC: 0.0008m3/m3 (0.08% VWC) from 0to 50% VWC 0.25% VWC (rockwool)
Temprature: 0.1°C
Range Ea: 1 (air) to 80 (water)
EC: 0-23 dS/m (bulk)
Temperature: -40-50°C
Dimensions 10 x 3.2 x 0.7cm
Cable Length 5m, custom cable lengths available upon request
Measurement Time 150 ms
Power 3.6-15 VDC, 0.3mA quiescent, 10mA during 150ms measurement
Output RS232 or SDI-12
Connector Types 3.5mm stereo jack plug or stripped and tinned lead wires (3)
Data Logger Compatibility (not exclusive) Decagon: Em50, Em50G, ProCheck
Campbell Scientific: CR200X - series, CR800/CR850, CR1000, CR3000, CR9000X
Other: Any data acquisition system capable of 3.6-15V excitation and serial or SDI-12 communication
Warranty One year, parts and labour

Non UK/Ireland Customers

Non UK/Ireland Customers, please contact Decagon Devices at:

5TM Volume

5TM Sensors


Click here for the Soil Sensors Comparison Page

5TM Manual
Size: 246.7 KB (252,622 bytes)

Soil Sensors Quick Start Guide
Size: 1.5 MB (1,533,464 bytes)

Environmental Catalogue
Size: 2.5 MB (2,581,813 bytes)

Quotation Request

Email us to request a quotation for the Decagon 5TM Soil Moisture and Temperature Sensor