The ability to control light is a grower’s most powerful tool. A smart LED grow light system can provide a business advantage, by producing the right amount of light and even light at specific wavelengths chosen to match the needs of both plants and growers.  


Light quality refers to the colors of light, or the spectrum provided to your plants. The mix of colors in light strongly influences plant development. The blue, green and red spectral range (400-700 nm) is referred to as PAR (photosynthetically active radiation), the range of light that plants use for photosynthesis. Light outside of PAR, including far-red (700-800 nm), is also of importance to plant development, from plant architecture, to speed up growth and promoting flowering. 

Spectrum with highlighted Far-Red

FR can be provided to the plants in various ways. For example, at different timing like end-of-day (EOD) FR, or constant FR in the spectrum.  

Our research on tomato seedling showed that EOD FR gave even taller and thicker stems than grown with constant FR. Research on cut chrysanthemums shown that with EOD FR, stem elongation was already observed after two weeks while stem weight was not affected. Also, EOD FR results in longer flowering shoots and flowers were harvested two days earlier than grown without EOD FR. The stems of marigold also respond to far-red and can be used to control stem length with the greatest height found under EOD FR. By adding Far-Red at the end of the day you will be able to use less energy, so there is potential for energy savings while achieving FR crop responses. 

Freesia, with no far-red, with far-red and with far-red at the end of the day

Far-red can also be used at different times in production. In the case of petunia and geranium, applying far-red treatment to the seedlings resulted in earlier flowering compared to untreated ones.  

There are many interesting potentials and Heliospectra always strives to get deeper understanding by working closely with our collaboration partners. For example, there may be potential to steering crops such as tomatoes using far-red, and research is ongoing. 

The potential of using far-red when it is most beneficial for the crop is possible with Smart LED technology. By using a flexible light like MITRA X Flex the grower has the possibility to have an efficient light and steering the crop by have far-red on or off. Whether this is to get specific responses, to adapt to season or to be flexibility due to crop changes in the greenhouse.   

LED grow light, Mitra X Flex


Far-Red ebook

Download our new free e-book and discover the future of farming with Heliospectra’s Far-Red knowledge. Learn how to maximize growth potential with our Smart LED technology. 

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Runkle, E. (2016, May). A Closer Look at Far-Red Radiation. 

Park Y, E.S. Runkle (2018) Far-red radiation and photosynthetic photon flux density independently regulate seedling growth but interactively regulate flowering. Environmental and Experimental Botany. 155. 

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