SM150T Soil Moisture Sensor

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Soil moisture sensor Zoom
SM150T Soil Moisture SensorSM150T Soil Moisture Sensor in raspberry plant potSM150T Soil Moisture Sensor – buried in grow bagThe 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-warrantyStable and accurate (± 3%)
  • Robust and buriable with 5 year warranty*
  • Accurate substrate moisture monitoring
  • Ideal for precision irrigation

The SM150T is an affordable soil moisture and temperature sensor that is ideal for system integrators

SM150 Sensor – a versatile sensor for growers and system integrators

The SM150T is the perfect sensor for a wide range of applications in horticulture and agriculture. It can be used in both soils and substrates and is buriable. In addition, the SM150T offers excellent salinity and temperature stability.

The SM150T is a reliable and cost-effective solution for system integrators, who appreciate its ease of installation and simple interface (0 – 1 V DC output).

SM150 Kit – for instant readings

The SM150 Kit combines the SM150T Sensor with a handy readout meter, providing growers with a low cost, portable, and easy to use tool for obtaining instant accurate moisture measurements. Find out more about the SM150 Kit.

NB: When used in portable mode the SM150T Sensor does not provide temperature indication. To record temperature the sensor must be fully buried and connected to a suitable data logger.

Combined SM150T image for web pages smaller x 1000

Easy installation

The SM150T’s sharp pins minimise soil disturbance, preserving the original soil structure around the measurement rods, and making the probe easy to insert and install. For burial at depth the cylindrical shape facilitates installation in augered holes. Optional extension tubes assist with placement and removal (50 cm and 100 cm lengths, connectable).


Horticulture – In kit form (see SM150 Kit) the SM150T Sensor comes with calibrations for mineral, peat mix, coir, mineral wool and perlite (plus also provides raw voltage output) – providing a simple, effective, rugged solution to checking the uniformity of growing conditions for many types of growing media.

Precision Irrigation – Accuracy and ease of use make SM150T Soil Moisture Sensors well suited to precision irrigation applications. The SM150T’s compact size (143mm total length – rods 51mm long) allows it to be easily installed in plant pots or grow bags. Readings can be used to optimise irrigation scheduling, or the SM150T can be installed as part of an automatic irrigation system.

System integration – The SM150Ts accurate and stable measurement (± 3% for 0-70% VWC** range), simple 0-1 V output (moisture), and low power (18 mA for 1 second) makes it the ideal sensor for system integrators.

Patented sensor electronics produce research-grade accuracy performance alongside exceptional salinity and temperature stability – an essential combination for critical control and precision irrigation decisions.

Industrial rated, UV resistant cable fitted with a waterproof IP68 connector allows the sensor to be buried indefinitely, whilst still permitting easy cable exchange or extension if necessary.

More information is available in the SM150T System Integrator Data Sheet.

Data logging

The SM150T is compatible with all Delta-T Devices Data Loggers and its 0 to 1 V DC output can be handled by most other types of data logger. Temperature measurement (10 K thermistor) requires burial of the probe.

Product history

The new SM150T replaces both the SM300 and SM150 Sensors, combining their strengths and offering great value.
* Extended 5 year warranty requires online registration.

**Volumetric water content




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