New Red LED to Boost Greenhouse Horticulture Production

SIEMENS subsidiary Osram Opto Semiconductors has developed a powerful LED for use in plant cultivation.

The new LED emits a deep-red light at a wavelength of 660 nanometers, the ideal light for plant photosynthesis. The LED has an efficiency of 37%, which is one of the highest for a light source of this colour, and yields considerable energy savings compared to conventional lamps. 5000 of the new LEDs were used in a pilot project in Denmark to illuminate a cultivation area of several thousand square meters.

The trial saw power consumption in the greenhouse fall by 40%.

According to Siemens, relatively little of the light used by plants for their growth is from the visible light spectrum. Chlorophyll molecules mostly absorb deep-red and blue light for the purposes of photosynthesis. The efficient red LED from Osram Opto Semiconductors has an emission curve that is very closely matched to the spectral sensitivity of chlorophyll. The new LED is based on the thin-film technology used for high power semiconductor chips.

In greenhouse cultivation, some plants are grown on several levels stacked on top of one another. For this reason, the new LED is available in two variants, each with a different beam angle. The Golden Dragon Plus has a beam angle of 170 degrees and is well suited for use in reflector lamps for illuminating large areas under cultivation. The Oslon SSL LED, with a beam angle of 80 degrees, is designed for use in multi-level applications, such as those for the cultivation of lettuce.

Using LED light, it is also possible to promote different growth phases of the plant under cultivation. Red light, for example, encourages plants to grow in length, whereas blue light fosters bud formation. Controlled variation of the proportion of blue light between ten and 30 percent can reduce the use of fertilizer and other chemicals.

The developers claim that compared to conventional high-pressure sodium lamps, the luminous efficacy of the system as a whole is 60% higher with red and blue LEDs. The diodes have a service life of 100,000 hours for maintenance-free operation for many years.

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This sounds pretty interesting for greenhouse growers, especially in higher latitudes where daylength and daylight is severely restricted in winter months. Even if only partially as effective as claimed.

As an aside.........I am sure that hydroponic marijuana growers will also find an exciting use for the technology too! [I am not advocating its use] Reports seem to indicate they usually apply the latest and greatest technology.