Customized Solutions for High-Tech Greenhouse Research

Phenotyping Innovation

The Netherlands Plant Eco-Phenotyping Centre (NPEC) is a joint initiative by Wageningen University and Research and Utrecht University, co-funded by the Netherlands Organisation for Scientific Research. This state-of-the-art institution researches genotype-phenotype associations to develop climate-proof crops and secure future high-quality, sustainable food production. At NPEC, researchers work at the forefront of agricultural phenotyping, and foreign scientists travel to tour their facilities and receive research inspiration. NPEC offers a model for integrating precise, automated monitoring into greenhouses. 

NPEC is a multi-unit, high-throughput research initiative that includes fields with drone monitoring, grow rooms, and high-tech greenhouses. Their goal is to measure as many plants of as many species as possible. Since opening the greenhouses in 2023, they have researched: 

• Effects of Verticillium fungi in the soil on potatoes
• Drought and salinity on tomatoes, wheat, and quinoa
• Cross breeding wild and cultivated lettuce varieties to build robust, edible varieties
• Peas, strawberries, ornamental flowers, and more! 

Their greenhouse utilizes automation to track plant metrics and control climate variables such as lighting, temperature, and humidity. This system also allows each plant to be watered individually and weighed. Their self-developed imaging systems capture 3D images, photosynthesis efficiency, chlorophyll index, anthocyanin index, and biomass. In two of the four greenhouse compartments, a sophisticated conveyor belt system carries potted plants through the imaging chambers. In the other compartments, cameras are mounted on overhead gantries to avoid stressing delicate plants.  

Take a virtual tour of their greenhouse facilities.

Unique Measuring Conditions

NPEC’s forward-thinking architecture introduces unique challenges for environmental monitoring: 

• When mounting sensors, they must consider the movement of conveyor belts and overhead gantries. Monitoring equipment must avoid interfering with machinery while capturing data that represents the environment of plants across the building.
• The greenhouse’s advanced setup involves reflective steel and moving parts that interfere with even light distribution. They use lamps with known light spectra and pyrgeometers to measure incoming solar radiation, but the complex light gradients make it difficult to estimate how much light reaches the plants.  

Beyond the physical constraints, NPEC’s scientific goals demand reliably continuous, high-resolution, real-time data on climate variables. Tim van Daalen, a current researcher at NPEC, explained, “temperature and PAR are key drivers for the growth of plants and therefore often lay at the basis of growth simulations." These parameters are essential to revealing phenotypic differences in drought resistance, yield, fruit taste, produce quality, ease of harvest based on how stems lay, vertical growth for industrial efficiency, and more. Each variable triggers unique responses for each plant genotype, so precise environmental monitoring is essential.

Tailored Monitoring Solutions from Apogee Instruments

NPEC needed monitoring tools that were compact, highly accurate, and easily integrated into their automated data workflow. Rick van de Zedde, program manager of plant phenotyping, shared that their scientific community has come to accept certain light measurement systems, and Apogee’s sensors are one of the trusted solutions. Through collaboration, Apogee’s engineers developed approaches that solved NPEC’s specific challenges.

Temperature and Humidity

The team at NPEC has come to love The Guardian, an all-in-one, agricultural environment monitor that measures PAR, air temperature, relative humidity, vapor pressure deficit, dewpoint, CO2 concentration, barometric pressure, daily light integral, and photoperiod. A built-in fan maintains air flow to collect accurate data.  

The Guardian’s compact design allowed it to be mounted on stands between conveyor belts—over the moving plants, and under any overhead gantries. This is much simpler than installing separate instruments for each measured parameter in multiple locations around the greenhouses. While sharing about a current experiment that has revealed some important growth differences between pea plants, Tim praised the monitor’s mobility; “With the guardian we only have to move one sensor to analyze the climate in the area of interest, saving quite some time and effort.”  

The team also found that the Guardian’s low-maintenance humidity probe was a great improvement from the wet bulb sensors they had been using previously, which required frequent wetting to stay accurate. Meanwhile, the Guardian’s probe can simply be left to do its work. The benefits here are twofold: First, it reduces time and attention spent on maintenance. Second, the monitors can be installed deep within the greenhouse canopy, capturing measurements that better reflect real growing conditions, without needing to periodically disturb the plants.  

Rick shared that in the past, they have had research papers rejected for publication because of data gaps when a sensor battery went out without warning or sensors were providing inconsistent data. The Guardian solves this with high quality sensors, reliable Bluetooth or Modbus connectivity, and optional indicator lights that show connection status. Rick shared “we have been using the Guardian on a daily basis; so far, we have not missed a single day... Simply, it’s been a reliable sensor, useful, and it has become a fundamental tool of collecting environmental characteristics.” 

Light

According to Tim, “[Plant] response to lighting has shown to be more complex. The light color, intensity and light sum all have different effects.” It’s crucial they have lighting data that reflects the light their plants really receive in a day; their growth modelers consider this data as they compare the growth model to the actual plants. But, he explained, “Due to all the additional steel for the conveyors and other moving parts it turned out to be challenging to correlate the outside light intensity to the light intensity inside the compartment.” The light measured at one sensor head would likely be an inaccurate sample.  

To resolve this, NPEC installed Apogee’s PAR Bars. These sensors feature 10 photodiodes in a line, spaced about 5 cm apart. This design provides an average light intensity in an area, providing generalizable data for the greenhouse.

Data Upload

Apogee offers sensors with a range of connectivity and communication options, which simplifies integration into an existing system.  NPEC uses our compact µCache datalogger with each PAR Bar to provide Bluetooth connectivity and continuous data collection. Although the µCache is typically battery-powered, our engineering team wired it for NPEC to lower maintenance and avoid interrupting experiments to replace batteries. The Guardian is already Bluetooth enabled.  

To automatically transfer collected data to their online database, we developed a software called Apogee Connect for Raspberry Pi, available to any Apogee user for free. This allowed all their Bluetooth sensors to connect to a Raspberry Pi, which automatically uploads the data to NPEC's server. 

To improve the quality of ongoing experiments, live sensor data is displayed on TV screens throughout the facilities. They’ve found this can spark creativity or increase awareness for their scientists. Plus, as greenhouse managers know they can rely on their data and its seamless collection, projects can be scaled up without compromising quality. 

Better Data Now; Better Plants to Come

During a recent visit to NPEC, members of the Apogee team had the opportunity to see their strawberry research up close. The study targets phenotypic traits that offer practical benefits for growers, such as strawberries that are easier to harvest for increased efficiency and drought resistance to reduce crop loss. They also are looking for narrower plants that maintain fruit volume, which increases yield as more plants can fit in an available space. Our team sampled the strawberries, which tasted delicious and gave us a taste of the quality of their work!  

By linking plant genetics to environmental responses, NPEC’s research is doing the groundwork for climate-resilient, high-yield crops. By combining advanced automation, environmental control, and precise data from Apogee sensors, they’re unlocking breakthroughs in phenotyping that will shape the future of agriculture and our food system.