LED used as grow lamps should be different from those which are used for lighting in a house, school, or office. This is because the environment which exists in a greenhouse or indoor farm, and the light needs of plants are different.
Conditions in Growing Environments
In greenhouses and indoor farms, there is far more humidity in the air than in houses. There is also some amount of natural light coming in greenhouses. Moreover, the light which plants need can defer in many aspects to what people need. This can be the colour of light, the intensity of light, light temperature or even its placement. Therefore, grow lights which just assemble generic LEDs are not very effective. In addition, there is a difference in the light environment between greenhouses and indoor farms which is just beginning to receive attention.
Ideal Grow lights
Keeping in mind the light needs that plants have, there are four aspects that should be optimally considered while producing luminaires.
Plants have different needs during the growing, flowering and fruiting stages. Taking advantage of the narrow bandwidth in which LEDs occur, the correct colour combinations can be used at each stage to manipulate plants to increase their yield.
Light quality or Color
However, each colour by itself also falls within a range of wavelengths (1). These are,
Violet : 380-450 nm
Blue : 450-495 nm
Green : 495-570 nm
Yellow : 570-590 nm
Orange : 590-620 nm
Red : 620-750 nm
This means a red light with 620 nm is different from a red light of 750 nm. Science usually specifies the wavelength at which each colour should be used. When LEDs are prepared for horticulture, the specified wavelength can be used. Moreover, the wavelengths can vary for different flowers and vegetables, and so targeted spectrums for each flower or vegetable are prepared.
Light intensity for horticulture lights is measured in terms of Photosynthetic photon flux density (PPFD), where only the light spectrum used by plants called Photosynthetic active radiation (PAR) is measured.
In commercial flower and vegetable production, the intensity of light which is supplied to plants is as important as the colour. While this is especially true for the flowering and fruiting phases, light at specific intensities can also control pests and diseases.
Position of lighting
To ensure that plants are uniformly lit from top to bottom, inter-lighting is important and can improve yield significantly. These light units have to be designed very differently from lights which people use, and in the correct intensities so that plants are not harmed by excess radiation.
LED grow lights which can withstand humidity are necessary for growing environments. Otherwise, they can be affected just like any other electronic gadget. Damages can reduce LEDs’ efficiency and also its lifespan.
What is not important for plants is colour temperature which is measured in Kevin. This is important for people and will differ based on the tasks they undertake; they do not need to be considered in improving plant yield.
LEDS for Plants
Since the grow lights have to meet specific needs, LEDs customized and manufactured for horticulture will be more effective in improving plant performance and yield. These do not cost more than generic LEDs, so it is worth spending time and effort in finding the right kind of LED grow lights for your plants.