Signify has introduced a new efficient LED light recipe with red, blue, green, and far-red light that has an added value for strawberry cultivation. The addition of far-red light to the usual red/blue spectrum encourages the stretching of stems and trusses in winter, allowing some varieties to use the available PAR light more effectively. Two Belgian growers have now equipped their new greenhouses with Philips LED GreenPower toplighting compact (TLC) grow lights with the new FR_5 spectrum.
The FR_5 spectrum contains red, blue, green, and far-red light. The far-red light provides more opportunities for strawberry growers – among others – to set up an efficient, high-quality winter production or to optimize their existing production. Varieties that stretch less easily in the depths of winter with full LED without far-red light often do better with this new spectrum.
Plant specialist Peer Hermans of Signify says: "Little daylight is available in winter, and the lighting installation provides a large part of the total light sum. When the grow light contains too little far-red light, some strawberry varieties can stay very compact. The leaves intercept less light and are quickly in each other's way at the expense of photosynthesis. Less stretching of the trusses also means that the fruits will not hang as low, making the harvest more difficult. Furthermore, a more open crop produces a more favorable microclimate."
Hermans emphasizes that this new spectrum shouldn't be seen as a universal solution for all strawberry varieties. "Some varieties perform better without additional far-red light. Others clearly benefit from it," he explains. "If the so-called 'ideal light recipe' for strawberries actually exists, it is yet to be discovered. The fact remains that this solution really works for several companies."
Efficient with far-red
Signify has put multiple years of research into developing a better full LED light recipe and integrating this into an efficient module. In terms of energy usage, the addition of far-red light leads to a slightly lower efficiency, but the Philips LED GreenPower toplighting compact (TLC) armature in which the spectrum is now available for multiple cultivations (including strawberry) makes up for a lot. The high light yield and ditto efficiency keep the energy usage to a minimum, making the transition to winter cultivation under full LED justified. The trust the growers have in this configuration becomes apparent from the recent investments of Belgian strawberry producers Fresa from Beveren and Fragaria from Oostkamp.
Optimal energy usage
Entrepreneurs Alain Lutz and his wife Hilde van De Vijver (Fresa) cultivate 6.5 ha of strawberries, of which 4 ha is under glass and 2.5 on trellises beneath foil. In the spring of 2022, a new greenhouse of 2 ha will be added, equipped with Philips LED GreenPower toplighting compact and the Philips GrowWise Control System. "We really wanted to grow and optimize our energy usage," Alain explains. "In order to achieve this, we must be able to produce year-round, so we needed grow lights. HPS lamps are far too expensive to use at the current prices. Full LED is the only option for us, but specifically with the addition of far-red light. Signify's solution came at exactly the right time for us."
The new greenhouse will have two similar compartments, one of which is dedicated to winter cultivation. The light plan for this compartment consists of 207 µmol/m2/sec extra grow lights in red, blue, green, and far-red. The second compartment is designated for the spring- and autumn cultivation. Because more sunlight is available during these months, the additional grow light is limited to 105 µmol/m2/sec. Thanks to the Philips GrowWise Control System, the light sum can be lowered on sunny days, thereby using less electricity.
Making the CHP installation profitable
Kris and Cedric Deguffroy of Fragaria are building a new greenhouse of 5 ha. "My son Cedric has just joined the company and wants to grow year-round in an efficient way," says Kris. "To justify the investment in a gas connection and a CHP installation, we have to scale up considerably; the current area is 3.5 ha glass, foil greenhouse, and trellis cultivation."
Fragaria has chosen the Philips LED GreenPower toplighting compact as well, with two different light plans: 2.5 hectares of 240 µmol/m2/sec with far-red light for winter production and 2.5 hectares of 150 µmol/m2/sec without far-red light for the spring- and autumn cultivation.
"We have looked at trials at the Philips GrowWise Center in Eindhoven, and I have spoken to fellow growers in the Netherlands who are already experienced with lit cultivation under LED," the strawberry grower continues. "Eventually, that resulted in us choosing Signify as a supplier. Reliability, product quality, and service are important factors in such investments, and Signify rates highly in these. We also like the fact that our installer, Mais Automatisering, is a steady partner of the lighting company. It gives us even more faith that our installation will do its job."