The Hanna Instruments HI 99121 Soil pH Meter, Item #51600, is a portable direct soil pH and temperature meter designed for field and laboratory-style spot testing of soil conditions. It is purpose-built for agricultural, horticultural, greenhouse, turf, nursery, and environmental users who need a fast, dependable method for measuring soil pH directly at the point of use. Rather than relying solely on bench workflows, the HI99121 enables direct insertion into soil and also supports soil slurry testing where a prepared sample method is preferred.

The meter is supplied with Hannas HI12923 dedicated soil pH/temperature probe, which is specifically engineered for soil analysis. The probe incorporates a rugged conical glass tip to support penetration into soil and semi-solid media, an open junction design to reduce clogging from organic matter, and a built-in temperature sensor for automatic compensation during measurement. Hanna also includes a ground auger to loosen harder soils before measurement, helping protect the sensing glass and improve field usability.

This platform is well suited for routine fertility assessment, root-zone monitoring, amendment verification, greenhouse media checks, and general agronomic troubleshooting. For operations that need portable, application-specific soil pH verification without overcomplicating the workflow, the HI99121 is positioned as a straightforward and durable field instrument.

Product Capabilities

• Measures pH and temperature simultaneously on a dual-line LCD display.

• Supports direct soil measurement and soil slurry testing.

• Provides automatic one- or two-point pH calibration with standard or NIST buffer sets.

• Includes automatic temperature compensation for more reliable readings across changing conditions.

• Offers pH-mV mode for electrode check and verification.

• Uses the HI12923 dedicated preamplified soil probe with integrated temperature sensor.

• Features an electrode condition indicator for quick diagnostic feedback.

• Includes battery life indication and low battery detection.

• Provides user-selectable auto-off after 8 minutes, 60 minutes, or disabled.

• Uses an IP67 waterproof housing for rugged field use.

Industries of Use

Agriculture
Horticulture
Greenhouse operations
Nurseries
Turf management
Landscaping
Environmental field testing
Soil science research
Academic and extension programs

Key Benefits

• Direct soil measurement reduces testing time in the field.

• Dedicated soil probe improves fit-for-purpose performance in soil and slurry applications.

• Open junction design helps limit clogging from soil organics and debris.

• Automatic temperature compensation improves reading consistency.

• Portable IP67 construction supports demanding field conditions.

• Long battery life supports extended sampling cycles and seasonal use.

• Included auger and cleaning solutions support better field workflow and probe care.