Leaf wetness sensor


Leaf wetness—simplified

Diseases and infections can destroy an entire crop, but at the same time, applying fungicides is costly and time-consuming. If you’re deciding when to spray by monitoring leaf wetness with a resistance grid sensor, you’ll have trouble accurately determining wetness duration without a lot of extra work. You need an accurate sensor that is simple to set up with stable, consistent, easy-to-use thresholds like the PHYTOS 31.

Say goodbye to guesswork

The PHYTOS 31 lets you know leaf wetness in no uncertain terms. It measures both the onset and duration of wetness on a simulated leaf, which in turn predicts when the onset of certain diseases or infections may occur. It’s not only a more accurate instrument, it’s also the easiest to set up, making it a simple and straightforward solution to several problems.

Accuracy you can feel secure about

Only the PHYTOS 31 ensures that every water droplet is measured. It’s able to achieve this in a couple of different ways.

First, unlike conventional leaf wetness sensors, its resistance grid doesn’t use salt-laced latex paint which absorbs water. This gives it extra sensitivity to avoid false positives. So there’s no having to cull data to figure out if the sensor was really wet or not.

Second, PHYTOS 31 uses capacitance technology, so it can sense sub-milligram levels of water condensing on the surface, including frost and ice formation. That way you can establish a threshold that not only indicates when the sensor is wet, but also senses how much water there is. This kind of moisture clarity reduces guesswork and worry about accurately predicting disease conditions.

Simple as nature

When your moisture sensor mimics the energetics of an actual leaf, making measurements is a lot easier. There’s no having to paint your sensor’s non-resistance grid first to get good data. No creating thresholds. And no worrying about lots of wiring. Instead, all you have to do is plug the PHYTOS 31 into the ZL6 data logger, where wet and dry threshold ranges are already programmed in. The result: you save time.

Simple. Accurate. Simply accurate.

Through sophisticated, yet simple engineering, PHYTOS 31 delivers unmatched accuracy in an easy-to-use sensor. It saves you both time and labor, while reducing your worry and guesswork.

Request a quote Contact us Knowledge base PHYTOS 31


  • Accurate
  • Easy to use
  • Detect leaf wetness and ice formation
  • Sensitivity without false positives
  • Mimics a real leaf, so moisture will condense/evaporate as it would on a normal leaf
  • Plug and play capability
  • Use with the ZL6 data logger for remote data collection
  • No need to create thresholds when used with the ZL6 data logger






View GSA details



Length: 12.0 cm (4.7 in)
Width: 5.8 cm (2.3 in)
Height: 0.8 cm (0.3 in)

Operating temperature range

Minimum: –40 °C
Typical: NA
Maximum: +60 °C

NOTE: Sensors may be used at higher temperatures under certain conditions; contact Customer Support for assistance.

Cable length

5 m (standard)
40 m (maximum custom cable length)

NOTE: Contact Customer Support if a nonstandard cable length is needed.

Cable diameter

0.165 ±.004 (4.20 ± .10 mm) with min. jacket of .030 (.76 mm)

Connector types

3.5-mm stereo plug connector or stripped and tinned wires

Stereo plug connector diameter

3.50 mm

Conductor Gauge

22 AWG/24 AWG drain wire


Supply voltage

Minimum: 2.5 VDC
Typical: NA
Maximum: 5.0 VDC

Settling time

10 ms


300−1,250 mV (depends on excitation voltage)

Data logger compatibility

Data acquisition systems capable of switched 2.5–5.0 VDC excitation and single-ended voltage measurement at greater than or equal to 12-bit resolution.


Manufactured under ISO 9001:2015
EM ISO/IEC 17050:2010 (CE Mark)

California requires the following notice:

⚠️ WARNING: This product may contain chemicals including ethylene glycol, lead, nickel, styrene and cadmium, which are known to the State of California to cause cancer, birth defects or other reproductive harm. For more information, go to www.P65Warnings.ca.gov



Have a question or problem? Our support team can help.

We manufacture, test, calibrate, and repair every instrument in-house. Our scientists and technicians use the instruments every day in our product testing lab. No matter what your question is, we have someone who can help you answer it.

Email Europe: sales.europe@metergroup.com
Phone US: +1 509-332-5600
Phone Europe: +49 89 12 66 52 0

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