SM150T Soil Moisture Sensor

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Soil moisture sensor Zoom
SM150T Soil Moisture SensorSM150 Soil Moisture Sensor – buriedSM150T Soil Moisture Sensor in raspberry plant potThe SM150 Soil Moisture Kit


"Just to let you know that I’ve been delighted with the performance of the SM150T soil moisture sensors and accompanying GP2 data logger. They have been in action at an escarpment site in Iceland over a 2 year period - and have provided some extremely useful data." Nick Cutler
Lecturer in Physical Geography
University of Newcastle
"Working with Delta-T Devices, we installed two arrays of SM150T soil moisture sensors at varying depths - in selected well-managed plantations in the Santa Marta region of Colombia.

Choosing equipment that you have complete trust in to record the data you need, and, importantly, technical backup when challenges arise, were fundamental requirements for us. When you are running out of time (and daylight) in a remote banana field it was reassuring that someone at Delta-T was responding so quickly to our technical questions.

The Delta-T devices kit has been first class – it has not missed a beat since we installed the equipment. We now plan to leave the SM150T sensors in-situ after the project to continue developing our understanding of the soil-water fluxes under banana crops."
Prof Jerry Knox
Cranfield Water Science Institute,
Cranfield University, UK
"We recently purchased fifteen SM150 units. They are working excellently and are proving to be very robust and resilient." Aaron Schmocker
Bern University of Applied Sciences
"We used the instrument for 4 days of intense field work at 15 conservation areas across the Greater Toronto area - more than 200 readings per day. The sensor proved to be an invaluable asset to our research project. It is fast, light weight and very energy efficient." Nao Ito, Graduate Student
York University, Toronto
  • 5-year-warrantyDependable ± 3% soil moisture accuracy
  • Built in temperature measurement
  • Robust and buriable, with 5 year warranty

The SM150T measures soil moisture and temperature with research-grade accuracy. It offers stable, robust and reliable performance at a great price.

Research grade soil moisture sensor

The SM150T’s advanced patented electronics and tough build produce a highly reliable soil moisture sensor with exceptional salinity and temperature stability. The SM150T is engineered to withstand long term burial – the sensor, connectors and cable are all environmentally protected to IP68. It offers moisture accuracy of ± 3% (after soil specific calibration) and the built in temperature sensor achieves ± 0.5°C.

Data logging and readout

The SM150T is a dual purpose soil moisture sensor – it can be used portably for instant moisture readings, or left installed in the soil connected to a data logger, to provide long-term moisture and temperature data.

For installed sensors:
The SM150T can be logged by any Delta-T Devices data logger and by many loggers from other manufacturers (simple 0-1 V output for moisture, 10K thermistor for temperature). To record temperature the sensor must be fully buried and connected to a data logger.

For portable use:
The SM150T is available as part of the convenient SM150 Kit, complete with carry case and HH150 readout meter. Find out more about the SM150 Kit.

Please note that the HH150 Meter supplied with the SM150 Kit is a readout-only device. If PC connectivity for data storage and download is a requirement, the SM150T should be used with the HH2 Moisture Meter instead.

NB: When used in portable mode the SM150T Sensor does not provide temperature indication.


The SM150T Soil Moisture Sensor is easy to insert and install – its sharp pins minimise soil disturbance and preserve the original soil structure around the measurement rods. For burial at depth the cylindrical shape facilitates installation in augered holes. The threaded base of the sensor can be connected to optional 50cm and 100cm extension tubes, which assist with placement and removal.

The SM150T uses the same high quality range of cables and extensions as the ML3 and EQ3 sensors.


The SM150T comes complete with general calibrations for mineral and organic soils. A two-point soil specific calibration can be performed for greater accuracy if required.


Soil science – The SM150T is easy to install and provides accurate measurement of soil moisture and temperature – simplifying the vertical profiling of both parameters. (Temperature measurement requires burial of the probe).

Horticulture – With a length of only 143 mm (rods 51 mm), the SM150T can be installed in grow-bags and plant pots. For portable use, the SM150 Kit provides a simple, rugged solution to checking the uniformity of growing conditions across many types of growing media. Portable kit calibrations include mineral, peat mix, coir, mineral wool and perlite (plus raw voltage output). SM150T for Horticulture use.

Irrigation –
The accuracy and ruggedness of the SM150T Soil Moisture Sensor makes it a natural choice for system integrators – more information is available in the SM150T System Integrator Data Sheet.

Product history

The SM150T replaces both the SM300 and SM150 Sensors, combining their strengths and offering great value.


* Extended 5 year warranty requires online registration.





MeasurementVolumetric water content and soil temperature
Accuracy± 0.03 m3.m-3 (3%)
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 0.7 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 V with 100 m cable
EnvironmentalIP68 (-40 to +70°C)
Sample volume~55 x 70 mm diameter
Sample volume is weighted towards soil immediately surrounding the rods
Dimensions and weightOverall: 143 x 40 mm diameter
Rods: 51 mm x 2.5 mm diameter
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


Product Resources

Data Sheets

Case Studies




Regulatory Information