Light Measuring Protocol
A protocol to measure LED lighting in horticulture
Wageningen University & Research (WUR), in collaboration with advisors and manufacturers from the horticultural sector, has developed a new light measurement protocol for LED installations. Gavita International B.V. is one of the manufacturers that actively contributed to the development of this new standard, which provides growers with greater clarity and confidence in a rapidly evolving LED market.
A New Standard for Measuring LED Lighting in Greenhouse Horticulture
LED lighting in greenhouse horticulture is becoming increasingly advanced. Modern installations are dimmable, feature multiple independently controllable light spectra, and are often applied dynamically within crop strategies. While these innovations offer new opportunities, they also make light measurements more complex. At the same time, growers need reliable and reproducible measurement results to make well-informed investment decisions.
The new WUR light measurement protocol is designed to reflect current practice. It clearly defines how measurements should be carried out, which sensors may be used, and how many measurement points are required. In addition, the protocol includes a practical calculation tool that provides insights into key parameters such as average light intensity per spectrum and light uniformity within the greenhouse. For growers, advisors, and manufacturers alike, the protocol represents an important step towards greater transparency and comparability. Measurements performed according to a shared standard deliver consistent results—regardless of who performs the measurement. This helps growers better assess LED installations and builds trust in a market characterized by rapid technological innovation.
5 key points summarized
- Measure light without sunlight (preferably at night) and as closely as possible to the conditions in the light calculation plan (screens, crop presence, fixture height, number of LED rows on).
- Use a calibrated spectral light sensor to measure PAR and the individual light colours (blue, green, red and far‑red); standard PAR sensors are not suitable for LED measurements.
- Measure in two representative areas between LED fixtures, using at least 40 evenly spaced measurement points per area at the correct measuring height.
- Turn on the LED fixtures at least 30 minutes before measuring and make sure the intended spectrum and light intensity settings are active.
- Use the calculation tool to check average light level, uniformity and spectrum, and compare the results with the light calculation plan to confirm performance.
