WET KIT and WET-2 Sensor

    How to Buy
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"Optimising the quality and yield of our fruit is a key priority for Clock House Farms. By knowing the exact EC and moisture levels hour by hour we have the data that enables us to react quickly to changing substrate conditions.

It is the immediacy of the data which the WET Sensor provides that is valuable to us, not just the excellent accuracy.

In terms of benefits that the WET Sensor provides, it not only gives us the confidence that we have optimal growing conditions at all times, it has also enabled us to reduce irrigation levels (whilst enhancing produce quality) - eliminating unnecessary water wastage and reducing expensive fertiliser costs."
Nick Deppe, Farm Manager
Clock House Farm, Kent, UK
"We have used the Delta-T Wet Sensor since its introduction. This device has allowed us to have precise control over the EC in our strawberry and raspberry substrate grown crops; delivering better quality, flavour and yields. We could not manage without this excellent tool now." Harriet Duncalfe
H&H Duncalfe
"We've successfully integrated a large number of Delta-T Devices WET Sensors into our measurement systems. We use them continually - to provide EC, moisture and temperature measurements. This valuable data helps our customers to improve the yield and quality of commercial Cucumber and Tomato crops." Martin Drop
Hortitechnic, UK
  • Measures Water content, EC and Temperature
  • Measures directly within the root zone
  • Rapid checks of growing conditions

In just 5 seconds the WET Sensor checks 3 crucial variables that influence plant growth: water content, temperature and pore water conductivity (ECp), the EC of the water that is available to the plant.

Vital tool for precision horticulture

The WET Sensor is used throughout horticulture, especially by soft fruit growers and for crops grown in protected environments, where correct growing conditions are critical to both yield and flavour. The compact sensor can be inserted directly into the growing medium with minimal disturbance to either roots or shoots, and provides information for process optimisation or checking growing condition uniformity.

WET Kitwet-1

WET Sensors are normally ordered as a complete kit that includes a WET Sensor, an HH2 Moisture Meter and a handy carry case. There are three types of Kit – each with a different set of substrate calibrations, including coir, peat and mineral wool. Please see below for further information on substrate calibrations and kits.

Fertigation and hydroponics

Where plants are grown in artificial substrates using hydroponic or fertigation systems, nutrients are routinely supplied in irrigation water. Nutrient levels are controlled by monitoring the water content and conductivity (EC) and adjusting the injection of liquid fertiliser into the irrigation water. The Delta-T WET Sensor excels in monitoring this vital information.

Article featuring the WET Sensor – exploring Cultilene’s approach to measuring growing conditions in substrate slabs (HortiBiz 2015).

Container-grown shrubs and trees

Nutrients are sometimes provided by fertigation but are often provided by Controlled Release Fertilisers (CRF).

The rate at which these are taken up depends on several factors, including the weather conditions and irrigation regime.

The Delta-T Devices WET Sensor can be used to measure the EC within the growing media and so take much of the guesswork out of this process.

Soil salinity

If the irrigation water is recycled or abstracted from rivers and aquifers with high levels of dissolved salts, over time there can be a build up of soil salinity. Soil salinisation will eventually reduce crop yields. The WET Sensor is fast and efficient for sampling soil salinity, ensuring that farmers have the essential information they need to take remedial action as quickly as possible.

Readout and data logging

For portable applications, readout and data storage are handled by the HH2 Moisture Meter. Alternatively, the WET Sensor can be connected to a GP2 or GP1 Data Logger, making it possible to monitor growing conditions over a period of hours, days or longer. The GP2 and GP1’s smart relay capabilities allow them to control water content in response to EC or temperature.

Wet Kit Systems

Wet Kits are available with alternative sets of substrate calibrations pre-installed:

WET-2-K1 WET Sensor Kit WET-2-K1
WET-2/d WET Sensor, HH2 Moisture Meter and carrying case. Supplied with generic mineral, organic, sand and clay calibrations.
WET-2-K4 WET Sensor Kit WET-2-K4
WET-2/d WET Sensor, HH2 Moisture Meter and carrying case. Supplied with additional substrate calibrations including coir, peat-based potting mixes and greenhouse “mineral” soils.
WET-2-K3 WET Sensor Kit WET-2-K3
WET-2/d WET Sensor, HH2 Moisture Meter and carrying case. Supplied with basic substrate calibrations plus mineral wool vertical and mineral wool horizontal calibrations.

Standalone Wet Sensor

WET-2/w-05 WET Sensor (bare wires)

Combined water content, electrical conductivity and temperature probe. Includes sensor calibration on CD-ROM. 5m cable.

The WET-2/w is only suitable for use with the GP1 or GP2 Data Loggers and other specially enabled devices.  

If additional horticultural substrate calibrations are required, they should be ordered at the time of purchase of the GP1 or GP2 Substrate calibration upgrades are factory installed into the GP1 or GP2 at Delta-T’s premises. Please contact Delta-T Devices for further details.


The WET Sensor was developed in co-operation with:






Measured parameters
Permittivity, ε′ 1 to 80 ± 2.5 [1]
Bulk conductivity 0 to 300 mS.m-1 ± 10 (ECb)
Temperature -5 to 50°C ± 1.5°C
Calculated parameters
Volumetric Soil Moisture, θ 0 to 100% ± 3% [2]
Pore water conductivity see graph below (ECp)
Other specifications
Calibration Individual sensor calibrations stored within sensor EEPROM
Output Serial data (TTL)
Environmental IP68, 0 to 50°C
Power 6 to 10V, ~38mA for 2.5s
Dimensions ~120 x 45 x 13mm
Rods ~68mm long
Sample volume ~500ml

[1] Permittivity is a measure of the dielectric properties of materials, e.g. soils and substrates.

[2] Soil moisture accuracy refers to errors after applying a soil-specific calibration, within 10°C of calibration temperature.


For more detailed WET Sensor specifications see Soil Moisture Measurement Catalogue

Product Resources

Data Sheets

Case Studies



Technical Notes

Sensor Calibration File Locator

Input your serial number below (digits only - no slash or space required) to download your WET Sensor calibration file. The serial number can be found on the sensor’s blue cable label. Contact tech.support@delta-t.co.uk if your serial number is not recognised - and we will assist you directly.

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