LED and Planting

LED lights are popular artificial lighting systems used in hydroponic or soilless gardening. Some of the advantage of these grow lights include better growth of plants, less heat production and low maintenance cost.

Nabesei Co Ltd, a company specializing in electronic parts, demonstrated plants grown under different LED lights took place from April 15 to 17, 2009, in Tokyo.

Plants of the same size were continuously irradiated with light from a lighting device equipped with 630nm red LEDs, a device with 430nm blue LEDs and a pink-colored LED light composed of half red LEDs and half blue LEDs.

After three weeks of irradiation, the growths of the plants were compared with one another. As a result, it was discovered that the pink LED light most effectively promotes the growth of plants, the company said.

Plant do not need all wavelengths in the visible light range for their growth, but they absorb light with certain wavelengths to grow. When they perform photosynthesis or come into bloom, red light around a wavelength of 660nm, which is the absorption peak for chlorophyll, promotes the growth.

Meanwhile, when the plants form flower buds, blue light around a wavelength of 450nm promotes the growth.

When comparing the plants under the three kinds of light, those under the red LED light grew slower than others and were smaller as a whole. The plants under the blue LED light had fewer leaves and were spindly on the whole. On the other hand, the plants under the pink LED light had larger leaves and had generally grown in a more balanced way.

So there is a lot of DOE (Design of Experiment) in order to find out which wavelength would be best for the growth of the plants.

LED does contribute in Gardening and planting industry!