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Soil Moisture SensorsTM

Better Landscape, Less Water, More Savings with Baseline’s Soil Moisture Sensors

Using Baseline’s biSensor™ soil moisture sensors, you can create healthier landscapes and save time, money, and water in the process.  Baseline’s biSensor soil moisture sensors use patented technology to water better than any other technology on the market and biSensors save money because they reduce water usage—up to 62 percent or more over traditional irrigation methods.  They automatically self-adjust with the season, which means fewer trips to the field to adjust your irrigation controllers.  Simply put, you’ll love the results in your landscape and the savings of time, water, and money.

Baseline offers two different biSensors to meet your watering needs.

The 15-inch original biSensor is ideal for in-ground applications, and water feature monitoring. The 3-inch compact biSensor is ideal for greenroofs, greenwalls, and containers. The biSensors differ only in their dimensions; otherwise, they both have the same operating features and operating specifications. Either biSensor can be used in any application.

Baseline’s biSensors use patented technology called Time Domain Transmission (or TDT), to measure volumetric soil moisture and provide the most sensitive, repeatable, and accurate readings from the most durable device available.

Sensitivity.  The biSensor is capable of measuring volumetric soil moisture changes of less than 0.1 percent.  biSensors are a powerful tool for natural and engineered soils alike. 

Repeatability.  Always get the right reading, regardless of changes in soil salinity or other factors.  biSensors give you unmatched confidence in your irrigation system. 

Accuracy.  Soil moisture readings are within ± 3 percent of the actual volumetric soil moisture content.   biSensors allow for the best possible irrigation decisions from an irrigation controller.

Durability.  The biSensor has a rugged design that will stand up to the toughest conditions.  biSensors will give you year after year of dependable service for your irrigation system.

A Thermostat for your Landscape

Baseline’s biSensors are as effective at irrigating your landscape as a thermostat is at keeping your home a comfortable temperature.  biSensors measure soil moisture levels where it matters, in the root zone of the plant.

How it Works

Baseline Soil Moisture Sensors work by sending a high frequency pulse of electricity down an embedded wire path.  The high frequency of the pulse causes the sphere of influence to move outside the sensor blade and into the soil around it.  When the pulse travels through moisture, it slows down.  The sensor measures the speed, and then converts this measurement to a moisture content reading. 


  • Accurately measures soil moisture using patented modified TDT technology
  • Self-calibrates to all soil types and conditions
  • Soil moisture readings are within ±3% of the actual volumetric soil moisture content
  • Measurement ranges from 5% moisture to fully saturated soil
  • Capable of measuring changes of less than 0.1%
  • Measures soil temperature
  • Moisture readings are consistent in salty conditions
  • Sensor is completely sealed – no electrical contact with soil eliminates any electrostatic degradation or Galvanic corrosion of the sensing element
  • Power surge resistant
  • Shock resistant
  • Not affected by salts or fertilizers
  • Provides automatic and continuous measurements of soil moisture and soil temperature
  • Has true two-way communication using a 9-byte packet for commands and replies
  • Capable of self-identifying to the two-wire controller and will report pre-configured unique serial numbers
  • Has one pre-assigned serial number
  • Has standard error collision detections and will resend messages on the two-wire

Baseline’s Soil Moisture Sensors


  • Sensor has no electrical contact with soil
  • Freeze/heat resistant -4oF to 140oF (-20oC to 60oC)
  • Can only be connected to Baseline controllers
  • Requires 3M™ DBR/Y-6 Direct Bury Splice Kit wire connectors on the two-wire side
  • Requires all connections to be installed according to manufacturer’s instructions
  • Sensor element is constructed of a multi-layer fiberglass stick
  • Comes with 50 feet of 18-gauge (UL) direct burial, dual conductor irrigation cable (voltage rating: 300V, temp rating: 167oF (75oC)) to connect to the two-wire
  • Has a built-in temperature sensor used while calibrating the soil moisture readings
  • Has a conditional five-year exchange warranty
  • Sensor logic module measures 2” x 3” x 1” 
  • BL-5311 Compact biSensor
    • Sensor blade measures 3.2” x 3.25” x .075”
    • Measured volume is 4.5 cubic inches, or 0.25” on either side of the sensor
  • BL-5315B Original biSensor
    • Sensor blade measures 14.95” x 2.25” x .075”
    • Measured volume is 12.96 cubic inches, or 0.25” on either side of the sensor

Installation Specifications

  • Keep the maximum wire run between soil moisture sensor and the controller the same as stated in the two-wire specifications
  • Connect the soil moisture sensor to the two-wire per manufacturer’s specifications
  • Install the soil moisture sensor in a location representative of the zones that the sensor is controlling
  • Bury the soil moisture sensor in an area of average water distribution between two sprinkler heads and place it on the centerline between sprinklers
  • Install the soil moisture sensor 2-3 inches below the surface of the soil or in the top 1/3 of the root zone
  • Bury the soil moisture sensor so there are no air pockets or rocks in contact with the sensor
  • Mark the location of the soil moisture sensor so you can find it in the future and avoid damaging it when aerating
  • Make all splices inside a valve box with a 3M™ DBR/Y-6 Direct Bury Splice Kit connectors
  • Refer to the following installation guides, which include additional instructions:


Technical Specifications

Installation Details

Installation Guides

General Specifications

Advanced Programming

Supporting Documents

How to Specify

Part NumberDescriptionPrice
BL-APPMGRAccess to the AppManager FrameworkFree
BL-BMW2-LIVEAccess to LiveView through BaseManagerFree
BL-BMW2-PLUS1 year of BaseManager Plus service for 1 controller, includes WeatherAccess and Mobile Access Advanced service. PipeView is included in BaseManager Plus subscriptions for BaseStation 3200 controllers.$99 per year
BL-APPMGR-FLOW1 year of the FlowStation app service for 1 site$1,500 per year for each site

Note: For information about Baseline’s Mobile Access that turns your phone into the ultimate remote control, refer to the Mobile Access Brochure on Baseline’s website.

Designing with Soil Moisture Sensor Presentation