Quick verdict
A weatherproof Bluetooth data logger from Onset, whose HOBO loggers are standard in environmental research, paired with a METER TEROS 10 soil moisture sensor buried at the root zone, recording volumetric water content on a schedule and sending the log to a phone or tablet over Bluetooth. It is the instrument for an orchard, a vineyard, a sports field or a research plot that needs to know exactly how much water is in the soil and when, with the accuracy of a calibrated sensor rather than a probe meter. Priced accordingly.
Strengths
- TEROS 10 sensor gives calibrated volumetric water content
- Logs on a schedule for seasons on a battery
- Bluetooth download to phone or tablet with the HOBOmobile app
- Weatherproof logger for permanent field installation
- Onset and METER are research-grade names
Weaknesses
- Professional price, many times a probe meter
- Bluetooth range means visiting the site to download
- Sensor must be installed with care for good soil contact
The overall YardToolLab Score is out of 100. Section scores are out of 10.
Soil Moisture as Data, Not a Dial
A probe meter says dry, moist or wet. An orchard or a sports field needs to know how much water is in the root zone, how fast it leaves and when irrigation should start, every day, all season. That is a logger. Onset’s HOBO MX2306 is a weatherproof Bluetooth logger from the company whose instruments fill research stations, paired with METER’s TEROS 10 soil moisture sensor, recording volumetric water content on a schedule and sending it to a phone.
This review is based on the maker’s specifications and on how research-grade soil moisture loggers are used in irrigation management generally. We have not used this logger ourselves.
The Sensor
The TEROS 10 measures the soil’s dielectric permittivity and converts it to volumetric water content with a calibration that holds across soil types. It is buried at the root zone in undisturbed soil and left for the season. This is the sensor class used in agricultural research; its readings are numbers that can be compared and acted on.
The Logger
The MX2306 powers the sensor, records at the interval you set and stores months of readings on its battery. It is built for the outdoors and mounts on a stake above the buried sensor. Bluetooth Smart reaches a phone or tablet within range, and the HOBOmobile app downloads, graphs and exports the data.
What the Data Does
The curve shows the root zone filling with each irrigation and draining over the days after. Where it flattens, the soil has reached field capacity and more water is waste; where it falls to the stress point, irrigation is due. Growers set their schedules from that curve instead of a calendar, and the water and the crop both benefit.
Installation
Good soil contact is everything. Dig to root depth, push the sensor into the undisturbed side wall of the hole, backfill firmly and avoid air gaps. Install several across a field to catch variation. Record the depth and location.
Who Should Buy It
- Orchard, vineyard and nursery managers scheduling irrigation.
- Turf managers on sports fields and golf courses.
- Researchers and students in soil and crop science.
Common Owner Complaints
Price and the walk to download. Both are the nature of a field instrument without a cellular link.
Setup Tips
Pair the logger in the app before taking it to the field, set the logging interval to 15 or 30 minutes for irrigation work and give it a name that includes the site and depth. Install sensors at the depth where most roots are, and a second at a deeper depth if you want to see water passing below the root zone. Photograph the installation and record its GPS point so the sensor is found again at the end of the season.
Alternatives to Consider
The HOBO MX2308 with more sensor channels. METER’s own ZL6 logger with cellular upload. A probe meter for a home garden.
Verdict
For irrigation decisions on real data, a HOBO logger with a TEROS sensor is the research-grade tool at a price that reflects it. Install the sensor with care, log the season and water by the curve.
Full specifications
Onset HOBO MX2306 Outdoor Bluetooth Soil Moisture Data Logger with TEROS 10 Sensor FAQs
Volumetric water content, the fraction of the soil that is water, logged at the interval you set. From that you see how fast the root zone dries after irrigation or rain and when it reaches the point plants stress.
Dig to root depth, push the TEROS 10 into undisturbed soil at the side of the hole with full contact, backfill, and mount the logger on a stake above ground. Start logging in the app.
Walk within Bluetooth range with a phone running HOBOmobile and the log downloads. Export to a spreadsheet or view the graph in the app.
Growers and managers making irrigation decisions on real data, and researchers. A home gardener wanting to know when to water is better served by a probe meter.
