Irrometer tensiometers measure soil water tension, also called soil moisture tension: how hard plant roots have to work to extract water from the soil. The analog gauge provides a continuous, at-a-glance reading without electronics, making it useful for monitoring irrigation and comparing moisture conditions at different depths in the root zone.
Want to understand the readings? See our Measuring & Managing Moisture in Living Soil for a deeper explanation of soil moisture tension, mbar/cbar/kPa, sensor placement, volumetric water content (VWC), and using moisture measurements to manage irrigation.
Available Options ＋
Choose the model for the soil or growing media you are measuring, then select the length for the depth you want to monitor.
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Low Tension (LT), 0–40 cbar — for potting mixes, living soil, containers, raised beds, and other relatively wet or coarse growing media. Available in 6″, 12″, and 18″ lengths.
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Standard (SR), 0–100 cbar — for native and field soils where a wider tension range is useful. Available in 6″, 12″, and 18″ lengths.
How It Works ＋
The water-filled Irrometer exchanges moisture through its ceramic tip until it comes into equilibrium with the surrounding soil. As the soil dries, tension inside the instrument increases and the gauge reading rises. After irrigation, the reading falls as the soil becomes wetter.
Irrometer gauges read in centibars (cbar). Soil water tension can also be expressed in kilopascals (kPa) or millibars (mbar): 1 cbar = 1 kPa = 10 mbar.
Choosing a Length ＋
Length determines the depth of the ceramic tip and therefore the part of the soil profile you are measuring. A 6″ Irrometer monitors closer to the surface, 12″ reaches farther into the root zone, and 18″ is useful in deeper beds or when you want to track moisture movement lower in the soil profile.
Using Irrometers at more than one depth can show how deeply an irrigation event recharged the root zone instead of relying on a single measurement near the surface.
Service Kit Options ＋
Service kits make setup and maintenance easier by helping pull a vacuum inside the Irrometer. This removes trapped air, helps identify leaks, and speeds instrument response. Both service-kit options include Irrometer fluid/dye and instructions.
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Basic Service Kit — syringe, fluid/dye, and instructions for a simple way to pull a vacuum.
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Pump Service Kit — hand pump, fluid/dye, and instructions for faster vacuum service and leak checking.
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None — Irrometer only.
Important Notes ＋
- Irrometers must be filled and free of trapped air to respond properly.
- Good contact between the ceramic tip and the surrounding soil is important for a representative reading.
- Instrument length affects both measurement depth and the analog reading, so compare readings with the Irrometer length in mind.
- One service kit can be used to maintain multiple Irrometers.
