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
- Measures Water content, EC and Temperature
- Measures directly within the root zone
- Rapid checks of growing conditions
- Ideal for precision irrigation
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.
VIDEO – how the WET Sensor works
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, checking growing condition uniformity and precision irrigation.
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 for precision irrigation.
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 precision 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.
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 Sensors used aboard China’s Tiangong-2 Space Station
The WET Sensor has been used by Chinese astronauts to conduct horticultural experiments in space. find out more.
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:
|Measurement||volumetric water content||Pore water conductivity||Temperature|
|Accuracy||± 0.03 m3.m-3 (3%)||see graph below||± 1.5°C|
|Soil moisture measurement range||Full accuracy over:|
0 to 1 m3.m-3
|see graph below||0 to 50°C|
|Salinity range||0 to 300 mS.m-1|
|Supplied with extended range calibrations which should be used for readings between 300 to 500 mS.m-1|
|Temperature range||-5 to 50°C|
|Output||Serial TTL data providing permittivity, bulk conductivity and temperature, from which water content and pore water conductivity are calculated|
|Power requirement||6-10 V, ~38 mA for 2.5s|
|Sample volume||~500 ml|
|Sample volume is weighted towards soil immediately surrounding the rods|
|Dimensions and weight||Overall: 120 x 45 x 13 mm |
Rods: 68 mm x 3 mm diameter
Outer rods 68mm x 3.0 mm dia
Central rod 65 mm x 5.0 mm dia
Weight: 0.1 kg
|Sensor calibrations||Sensor calibrations supplied in WET Sensor EEPROM|
Recalibration advised every 3 years (dependent on use)
Generalised Mineral ,Organic, Sand and Clay calibrations are supplied, specialist calibrations are available for horticultural substrates (please enquire at firstname.lastname@example.org for more information) .
Main components and software
- WET-ST-1 – Calibrations Upgrade WET-ST-1
- WET-ST-1G2 – WET Stonewool Calibrations Upgrade for GP2 Logger
- WET-GH-1G2 – WET Horticultural Calibrations Upgrade for GP2 Logger
- WET-GH-1 – WET Horticultural Calibrations Upgrade for HH2 Moisture Meter
- WET-GH-1G – WET Horticultural Calibrations Upgrade for GP1 Logger
- WET-ST-1 – WET Stonewool Calibrations Upgrade for HH2 Moisture Meter
- WET-ST-1G – WET Stonewool Calibrations Upgrade for GP1 Logger
Mountings and enclosures
Cables and networks
Spares and consumables
Sensor Calibration File Locator
Input your 5 digit serial number below (do not include a slash or space) to download your WET Sensor calibration file. (Example: 28073).
IMPORTANT: If your serial number only has 4 digits, for example 22/19 – please add a zero before the last two digits – i.e. 22019
The serial number can be found on the sensor’s blue cable label. Contact email@example.com if your serial number is not recognised - and we will assist you directly.