"There’s no such thing as one perfect spectrum for a crop”

“There's no such thing as one perfect spectrum for a crop. It’s just too complicated: the ideal spectrum is a combination of different factors and is also cultivar dependent, but much more comes into play: the natural light at the cultivation site, the target light level, electricity costs and the produce sales price for example”, says Timo Bongartz with Fluence. That’s why the light supplying company is happy to expand their VYPR Top Light series with several new PhysioSpec spectra. With additional reflectors and mounting hardware, they want to offer greenhouse growers a broad toolbox to select their perfect light solution from. 

Diversifying the business
Just over two years ago the US company Fluence, specialised in horticulture lighting solutions, was acquired by the German Osram group and their ambitions have been clear. “Fluence has been an important player in the indoor market ever since we were founded in 2012. With the acquisition, further growth came within reach and the strategy has been to diversify the business. The greenhouse growers are a key part of that”, says Timo Bongartz, general manager for Europe, Middle East and Africa. “We’ve always seen that our LED products can be of help for growers of high wire crops, yet there are specific challenges that they deal with. Offering them our solutions and adjusting our portfolio, has been top of our mind.” 

With the expanded PhysioSpec Spectra the moment is there. In addition to the two existing spectra, the VYPR top light series now also can be equipped with additional PhysioSpec BROAD spectra as well as several red and blue DUAL spectra. Over the past years, extensive research was put into place to select these spectra. “Together with our research partners worldwide in the Netherlands for tomato, in Belgium for cucumber, in the US and Netherlands for cannabis, In Canada for bell pepper and in Germany for leafy greens and herbs”, Timo says. “Of course also the growers trialed the different spectra in their greenhouses. The combination of normal and applied science is what we selected the spectra on.” 

So what’s behind this choice? When talking about LEDs, it’s often about efficacy. “With our red and blue spectrum we can reach 3.8 µmol/joule and a PPF per fixture that goes up to 2330 µmol/s. That’s something we’re proud of since it’s one of the highest in the industry and these numbers are often important to growers. Yet there’s more to it: other than the light efficiency, also the plant efficiency plays an important role in the functioning of the light within the growing company as a whole”, Timo explains. He adds how Fluence does not want to step away from their broad spectrum strategy that has helped many growers so far. “But we’re broadening our solution sets for growers at any location worldwide and for all different kind of crops with the launch of these new PhysioSpec spectra.“ 

With expanded PhysioSpec™ spectra, the VYPR top light series offers higher efficacies (up to 3.8 µmol/J) and higher photosynthetic photon flux (up to 2330 µmol/s) per fixture over comparable lighting technologies. (Photo courtesy of Fluence by OSRAM) 

Broad spectrum lighting
“Finding the right lighting strategy includes more than finding the right spectrum or finding the right amount of lighting in terms of PPFD levels”, he continues. “A broad spectrum light could be the best spectrum when looking at the plants’ efficiency and overall yield but does not have the best energy efficiency. It is a case by case analysis to select the right spectrum together with the grower.” 

In order to realise the best company results, a grower would have to think of the best ROI. “And for example calculate their energy prices through. Red light is the most efficient to produce, whereas producing a broad spectrum is less energy efficient. The additional yield and the price you make for that yield, would have to justify the addition energy costs”, Timo shows.

He adds how for example Italian growers also would need different lights than growers in Sweden, since they would use a higher amount of supplemental light. “In the end finding the right spectrum is defined by different factors. If a cucumber grower in the Netherlands can change from traditional ambarella to high-wire cultivation and to winter production by adding supplemental lighting and that would improve revenue and profitability it is also important to consider the working conditions of the employees in regard to the color of light. That’s why we always speak with growers and find the lighting solution that suits their business, not a spectrum that suits only the crop. It’s not a one size fits all.” 

The new VYPR spectra - the DUAL spectra developed with a focus on energy efficiency and the BROAD spectra within the full PAR region of 400 to 700 nm - will give the team a broader toolbox to select from. “Especially in the LED industry there is so much yet to learn. We learn how plants are performing on different spectra and see the influence on plant architecture, the time flowering to harvest and fruit quality for example. That’s all valuable information for a grower and something he will base his business model on. Therefore we accompany all growers with our team of horticulture specialists to adjust and constantly optimize the cultivation under LED considering all growing factors.” 

"Fluence’s extended PhysioSpec™ spectra enable growers to optimize lighting strategies for any crop in any growth stage or geographic location", the team explains. (Photo courtesy of Fluence by OSRAM) 

Reflectors, mounting solutions and power supply
It’s not the only addition to the Fluence toolbox. Together with the new spectra also new reflectors and mounting solutions are launched and the VYPR series is updated with a patented thermal management technology as well as a more efficient and smaller power supply. 

“The reflectors can be used under the LED light fixtures and will give growers the possibility to distribute the light from a 120 to a 150 degree beam angle, which offers new possibilities in lighting designs and more ways to distribute the light uniform. Since HPS often has a beam angle of 150 degrees, we needed these reflectors also to realise nice overall and spectral uniformity for growers that want to opt for a HPS-LED hybrid installation.” 

With the additional mounting options the installation of the lights is more flexible ”Growers can put the lights under the trellis, perpendicular or next to it.” He explains how it is important to integrate your lighting solution already in the planning phase of the greenhouse, yet how this is often not possible - especially when working in an existing facility. “Working in a low greenhouse means the distance to the crop is limited and if you can gain an additional 20 centimeters just because of how you mount the LED lights that can already mean a huge difference in uniformity. It does not matter if it's the spectrum, beam angle or mounting brackets, it is all about finding the best fit for the individual needs of the grower.”