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Enabling better global research outcomes in soil, plant & environmental monitoring.

PHYTOS 31 Leaf Wetness Sensor

The Meter PHYTOS 31 leaf wetness sensor is standardised, calibrated, and designed to detect wetness (presence and duration) and ice formation right out of the box. No painting, baking, or user calibration required.

Sensitivity without False Positives

Each sensor is precisely factory-calibrated to detect tiny amounts of water and/or ice on the leaf surface. The sensor surface coating is non-hygroscopic, eliminating false wetness detection.

Mimics a Real Leaf

The sensor’s thin (0.65 mm) fiberglass construction closely approximates the overall radiation balance of a healthy leaf, so moisture will condense and evaporate from the sensor at the same rate as it would on a normal leaf.

Plug and Read

Get straight to the data with the Em50 series of data loggers. Just install the sensor, plug it into the Em50, set the clock and measurement intervals, and start logging leaf wetness data. No programming required.

Use the Leaf Wetness Sensor:

  • To predict when to spray crops.
  • To quantify water storage in the plant canopy.
  • In studying and monitoring crops for foliar diseases including rust and blight.


Utilising the Leaf Wetness Sensor in a custom IoT (Internet of Things)

The SNiP-LWS is a ‘Sensor Node Integrated Package’ for LoRaWAN communication of real-time plant leaf wetness/duration, indicating the potential development of disease and pathogens and, determining the appropriate time for use of preventative measures. This SNiP allows for continuous plant, light and environmental monitoring.

The base SNiP-LWS integrates 1x AD-NODE and 1x PHYTOS 31 Leaf Wetness Sensor to a site’s unique network, communication and power requirements.

The PHYTOS 31 measures leaf surface wetness by measuring the dielectric constant of the sensor’s upper surface. It has a very low power requirement, which gives you the ability to make as many measurements as you want over a long period of time (such as a growing season) with minimal battery usage. This sensor also has very high resolution, which gives you the ability to detect very small amounts of water (or ice) on the sensor surface. Water on the sensor surface does not need to bridge electrical traces to be detected, as is common with resistance based surface wetness sensors.

This means that the PHYTOS 31 does not need to be painted before use, which eliminates the need for individual sensor calibration.


Measurement Speed: 10 ms
Sensor Type: Frequency domain
Output: 320 – 1000 mV @ 3 V excitation
Operating Environment: -40°C to 50°C
Power: 2.5 VDC @ 2 mA, to 5 VDC @ 7 mA
Cable Length: 5 m standard, custom lengths available
Cable Connector Types: 3.5 mm “stereo” plug or stripped and tinned lead wires (3)
Sensor Dimensions: 11.2 cm x 5.8 cm x .075 cm
Data Logger compatibility (not exclusive): Meter/Decagon Em50 Series, ProCheck
EXPECTED LIFETIME: 2 + years of continuous use
Warranty: One year, parts and labour