Gdot Soil moisture monitoring system
Long range visibility, easy and simple to use, low maintenance and no wireless connectivity required. With over 20,000 units already sold, Gdot is an internationally established product which measures soil moisture, allowing monitoring and optimisation of water usage for the most economical improvement of crop yields. It is powered by 2 AA batteries and which typically last 5 years. The sensor has a 1.5 metre cable, which can be cut and spliced to a longer cable if required, up to a distance of 100 metres, and the display shows moisture levels using a simple sequence of bright yellow dots. The unit comes with a phamphlet covering the procedure and basic tools required for the simple installation process.

Soil water measurement is divided into two main types:
Volumetric measurement - measures the water content by volume in the soil; and Tensiometric measurement - determines the tension (force) required for plants to extract water from the soil, measured in Centibars (or kPa).
The GDot system utilises tensiometric measurement, where the ease of water uptake by plants is prioritised over just the water quantity. Soil water tension is critical because different soil types hold water differently even if the volumetric content is the same. By measuring tension, GDot ensures that it accurately reflects the real conditions the plants face, allowing for better water management without needing specific site calibration.

Benefits of tensiometric measurement
Adaptability to soil types: volumetric measurements may require site-specific calibration since different soils retain water differently. However, tensiometric readings directly relate to plant stress and water uptake ability, making them universally applicable without calibration.
Proven research: tensiometric methods have been researched since the 1920s, and the WATERMARK sensor used in GDot reflects these studies. These sensors measure soil water tension reliably, even in varying salinities, and are known for their long lifespan.

The WATERMARK Sensor
The WATERMARK Sensor is a ‘Granular Matrix Sensor’ that measures moisture levels through a specialised mixture of materials, or granular matrix. It electronically reads moisture absorption, unaffected by salinity, and lasts over five years. It mirrors traditional tensiometer readings while requiring no maintenance. Unlike traditional tensiometers, which need water replenishment and removal in winter, the WATERMARK sensor can remain in the ground year-round without any intervention.

Traditional tensiometers
A traditional tensiometer works by mimicking how a plant absorbs water. A ceramic tip interacts with the soil, creating measurable tension as the soil dries and tries to pull water from inside the instrument. While these are direct measurement devices providing precise soil tension data, they are prone to maintenance issues. For example, water levels must be replenished regularly, and the device must be removed in cold months to avoid damage from freezing.

The GDot advantage
The GDot soil moisture meter uses the WATERMARK Sensor to provide accurate and maintenance-free soil moisture monitoring. It offers clear benefits over traditional tensiometers with no need for manual calibration or seasonal maintenance. The sensor’s reliability, combined with a proven record of research and practical application, makes it an ideal choice for growers looking to optimise water use and maintain crop health across different soil types.