Is sunlight the "better" light?

Until now, we are used to plants growing in the wild with the help of sunlight. It is therefore normal that people are initially skeptical about Vertical Farming – because it is not the sun that shines here, but an LED light. But is this justified? We explain the different light spectra, their effect and necessities.

Isn't it sunlight which makes plants "healthier" or "tastier"?

The LEDs in the Plantcube were developed together with Osram. They generate the frequencies of blue to near-infrared light, so-called Far Red, which are important for plant growth. Also integrated are white LEDs with a spectral range that covers the colors green and yellow. These are precisely the wavelengths from the solar spectrum that ensure healthy plant growth (photosynthesis) and the expression of healthy ingredients (secondary processes). In short, the Salads, Microgreens and Herbs in the Plantcube get the same "good" light as they do outdoors – in fact, even a bit better, because there is neither too strong nor too weak sunlight that could reduce growth or the production of healthy ingredients.

Light spectra and their effect

By looking at the way plants absorb light to produce energy through photosynthesis, scientists have shown that blue and red light are the colors of light that plants can most easily use. As research progressed, it became apparent that the other colors of light also play a role in plant growth.

• Red light makes plants grow tall. Far Red also supports plants going into bloom to e.g. increase fruiting in tomatoes.
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• Blue, Yellow and Green generally drive photochemical reactions. So they are responsible for changes in plant appearance such as leaf shape, thickness and colour.
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• Blue is also a driver for the production of important and healthy phytochemicals.

What's special about our LEDs

With the LED light installed in the Plantcube, we cover the largest light spectrum compared to other products – with the red and blue range being more intense. This is the reason for the purple looking light in the Plantcube. However, green and yellow LEDs are also integrated, as well as the Far Red. So all the important light spectrums are present in the Plantcube to ensure healthy and strong plants. This allows us to adjust plant-specific light formulations for optimal growth. We are already working on making specific ingredients more pronounced through the proportions of the different light colors, for example to offer Rucola with higher vitamin C levels.

Duration and intensity of light

The amount of light per day (known as Daily Light Integral, DLI) plays a major role in the production of secondary plant compounds. Accordingly, when the DLI is increased, the production of secondary plant compounds also increases. Thus, if the amount of light per day is increased, more nutrient-rich and tastier plants will grow. This factor can also be used in a controlled manner in Vertical Farming. In Germany, for example, there is an average of only about 5 hours of sunlight per day over a whole year. However, our Plantcube provides the plants with the necessary light for a full 16 hours a day.

Conclusion

The LED light that we have developed and use for the plants in the Plantcube may therefore sound quite technical at first, but it is by no means worse than the sun. On the contrary, because we can adjust the light exactly according to the needs of the plants in the different growth phases, we give them exactly what they need. Every day. In the right dose.

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