ML3 ThetaKit

    How to Buy
ML3 ThetaKit - with accessories Zoom
ML3 ThetaKit – taking soil measurementsML3 ThetaKit – with carry caseML3 ThetaKit – including ThetaProbeML3 ThetaProbe metal rod layout


"We have ThetaProbe sensors installed at another site, some of them have been running for 8 years now and we've found them very reliable, so we'd like to use Delta-T Devices sensors again." Anu Riikonen, PHD Student
Department of Forest Ecology, University of Helsinki
  • Class leading ± 1% soil moisture accuracy
  • Complete kit with readout unit & case

The ML3 ThetaKit provides researchers with a portable tool for highly accurate, near instantaneous measurement of moisture levels in soils and substrates.

The ThetaKit is easy to use. Simply switch the connected HH2 Moisture Meter on, insert the probe pins fully into the soil, and press the HH2’s “read” button to display the moisture measurement. Readings can then be stored with a single button press (if required) – and downloaded to PC later.

The kit comprises an ML3 ThetaProbe Soil Moisture Sensor, an HH2 Moisture Meter (readout unit), replacement sensor rods, and a carry case.

Click here for details on the ML3 Sensor

NB: Other moisture measurement kits are available if lower cost or EC measurements are required.

ThetaKits are an excellent choice for turf grass applications.





MeasurementVolumetric water content and soil temperature
Accuracy± 0.01 m3.m-3 (1%)
With soil-specific calibration
± 0.5°C (0 to 40°C for temp sensor)
± 0.75°C (-20 to +60°C for temp sensor)
Soil moisture measurement rangeFull accuracy over:
0 to 0.5 m3.m-3
Full range : 0 to 1.0 m3.m-3
Salinity range50 to 500 mS.m-1
Salinity errors < 0.035 m3.m-3 from 0.05 to 0.4 m3.m-3. Can be calibrated up to 2000 mS.m-1
Temperature rangeFull accuracy over: 0 to 40°C
Output0 to 1.0 V differential
Corresponding to 0 to ~0.6 m3.m-3
Resistance 5.8Ω to 28Ω for temp sensor
Power requirement5-14 V, ~18 mA for 1s
Minimum 5.5 V with 100 m cable
EnvironmentalIP68 (-40 to +70°C)
Sample volume~60 x 30 mm diameter
Sample volume is weighted towards soil immediately surrounding the rods
Dimensions and weightOverall: 158 x 40 mm diameter
Rods: 60 mm x 3.2 mm diameter
(Rods are replaceable)
Weight: 0.1 kg (exc. cable)
Sensor calibrationsIndividual sensors are interchangeable
Recalibration advised every 3 years (depending on use)
Soil calibrationsGeneralised Mineral and Organic soil calibrations are supplied

HH2 Meter

Input connections1 water content sensor or 1 WET Sensor
Control outputs
Readings stored1,500
Recording rate
ConfigurationBy keypad
Communication optionsRS232 / USB [1]
Sensor excitation1 switched battery
Power1 9V 6LR61 (PP3)alkaline
Battery life (dependent on usage)~ 5,000 readings
Enclosure ratingIP54
Temperature range0 to +40°C
Display2 line x 16 character
Size125 x 80 x 45mm
Typical applicationsInstantaneous reading of soil moisture / profiles/ WET Sensor




Main components and software

Mountings and enclosures

Installation accessories

Cables and networks

Remote communications

Spares and consumables

Power options


Product Resources

Data Sheets

Case Studies




Regulatory Information