Introducing the Project
Precision Irrigation with Wireless Sensors: Driving Peat-Free Production in Ornamental Horticulture
The project is funded through ADOPT (Accelerating Development of Practices and Technologies), a multi-year funding programme within the UK Defra Farming Innovation Programme, delivered in partnership with Innovate UK.
ADOPT supports collaborative grower-led, on-site trials or experiments to generate, test, and demonstrate, innovative solutions that address commercial production challenges.
Project objective
Launched in 2026, this one-year project aims to demonstrate how wireless sensor technology can be used to support precision irrigation and nutrition management in the production of container-grown peat-free ornamental crops. The objective is to encourage wider industry understanding and provide confidence in using sensor data for decision support, encouraging broader adoption of the technology across the ornamentals sector. The one-year project involves a consortium of businesses and organisations including: Hillier Nurseries, The Farplants Group, RHS, HTA, and Van Walt. It builds on one of the main project objectives from the RHS Transition to Peat-Free Fellowship - to gain a better understanding of the irrigation and nutritional requirements of peat-free growing media.
Appreciating the exact levels of moisture and nutrition within growing media
The flow of data
A range of physical growing media metrics including volumetric moisture content, growing media matric potential, electrical conductivity, and temperature is measured by the various sensors installed within the crop. Data from the sensors is transmitted to local nodes which send it at set intervals wirelessly to the nursery gateway. From there the data is uploaded to an online platform to be accessed by authorised users. The information is presented as an easily interpreted ‘dashboard’ highlighting trends over time, with focus on the parameters most relevant to irrigation and nutrient management decisions. An ambition of the project is to explore how such systems could be integrated with nursery irrigation controls, enabling data-informed automation, while retaining grower oversight.
The data pathway from crop to office
What data is collected
The following growing media parameters are collected at set intervals by the sensors:
- Volumetric moisture content. This is the volume of water per unit total volume of growing medium, typically expressed as a percentage or ratio. It represents how much water is present in a given medium. This is recorded by WET 150 and Teros 12 sensors in the project.
- Growing media matric potential. This is the force in kilopascals (kPa) but is reported as the logarithmic measure pF, exerted by the growing medium to hold water. The value indicates how much effort plant roots must exert to extract water, acting as a direct measure of plant-available water rather than total water volume. This is recorded by Tensiomark sensors in the project.
- Electrical conductivity. This is a measure of a growing medium's capacity to conduct an electric current, indicating salinity levels, nutrient availability, and water content, usually measured in deciSiemens per metre (dS/m) or microSiemens per centimetre (µS/cm). This is recorded by WET 150 and Teros 12 sensors in the project.
- Temperature. This influences root activity, water uptake and nutrient availability and is recorded in centigrade (°C). This is recorded by WET 150 and Teros 12 sensors in the project.
Positioning the sensor within a pot
Project delivery
Several ‘gateway-node-in-pot’ wireless sensor systems have been set up at both Hillier Nurseries and Farplants within commercial crops. At Hillier Nurseries both longer-term shrub crops and shorter-term herbaceous crops will be monitored, while at Farplants the focus will be on relatively quick turnaround pot-grown bedding plants.
All the crops will be grown under protection on beds with overhead and sub-irrigation. Pot sizes will vary from one to three litres, but monitoring of smaller pot sizes may also be explored. The data generated will be used by the growers to inform cultural decisions relating to both irrigation and fertiliser applications. The trial will be in place through the spring, summer and into autumn/winter of 2026.
Three types of sensor are being evaluated, the WET 150 sensor from Delta T, the Teros 12 sensor from The Meter Group (Hillier Nurseries only) and the Tensiomark sensor from ecoTech Umwelt-Messsysteme GmbH. The sensors have been integrated into a bespoke wireless system by Van Walt who are also supplying technical support throughout the project. Demonstration events and relevant project output are planned throughout the life of the project.