LEDs, being monochromatic sources and being available in wide range of pure colors, are the only light sources that can be tailored to give right spectrum & do wonderful things for plant growth. Plants grow quicker and healthier than under other, traditional lighting methods such as HPS, and if the LEDs are good, then even better than under natural sunlight.
Most popular plant growth LEDs lights are purple/pink Not All light sources contain a full spectrum of colors – some light sources contain some of the colors. however Sunlight contains all spectrum colors and it feeds plants with either energy to trigger certain metabolic reactions or influence the behaviour. Different color LED chips placed inside the light, give different kind of response from plants. It is said that, if we want plants to grow tall, increase the amount of far-red, yellow, orange and green chips inside the luminaire. If we want plants to be compact, put more blue or UV colored chips. It seems, these kinds of responses are encoded in plants’ DNA and when designing LED lamps, we can count on plants responding the way nature has designed them to.
Two essential light colors to be placed in an LED lamp are: red and blue.
Red is the main component needed for photosynthesis and stem elongation inhibition. Additionally, it signals to the plants that there are no other plants above it and that it can thus have uninhibited development.
Blue stimulates stomatal opening, stem elongation inhibition, leaf expansion, curvature towards light and photoperiodic flowering.
The combination of these two sets of effects will, in simple terms, get the plant from seed to the vegetative stage and eventually to flowering, but much slower than under continuous spectra a.k.a spectra that contain more than just red and blue. Adding some other spectrum colors such as green, could enhance the leaf expansion rate and stem elongation, which in turn results in higher biomass (yield) accumulation. Adding UV wavelenghts affects the accumulation of compounds such as phenolics which could boost the flavor of the end product or its health benefits to humans. Kwality Photonics has played a responsible role in the research work on plant growth in few Indian Universities since last 10 years - Hyderabad Central University, Assam University, BITS Pilani-Goa etc , by designing & delivering tailored spectrum LED sources in high & very high power configurations with controls easy enough to be used by Biologists ( as opposed engineers). In near future, Kwality Photonics LEDs group would like to help any commercial enterprise to produce indoor tabletop leafy vegetable plant growing appliances. They research the plant behaviour & we do the LED & the engineering !
Our research says, not any red or Blue will suffice. There are specific wavelengths within the Blue 400-460nm band and the Red 600-800nm Bands. We understand this and produce propreitory narrowest possible spectrum of the desired peak wavelength. Further, the intensity and the exposure time cycles can be played with, to optimize the yields, much higher than just steady lighting 24/7.
Can one use normal led lights to grow plants indoors?
Can I use normal led lights to grow plants indoors? - Quora 2013 Yes, regular LED bulbs can be used to grow plants in house - but suboptimally. As Blue has major role, A coolwhite LED of 6000K CCt containing higher amount of blues is preferred over warmwhite LED containing less blue but more Red color. In either case there is wasted energy in green part of the spectrum. Total expended cost of Power will decide the viability of bio produce, so go for Blue & Red lights, for growing plants.
Edit Oct2018: I’ve become wiser to know that several other colors can be used by the plant growers to manipulate the rate of growth, succulence, the color and the taste of the fruit/leaf ! Here is the summary. Here is the summary in terms of the spectral distribution:
Fig 3. Spectrum of the Midday Sun (Yellow) & Plant Photosynthetic Function Distribution PPFD
Grow Light LEDs & Linear Lights for Plug n Play use by Housewives & Horticulturists
Listen to the producers & users from abroad & India
"When plants grow, they live off two main colors–red and blue. Red light is essential for photosynthesis and is responsible for controlling your plant’s height. This red light also lets your plant know that it has no competition in light absorption and it is free to fully grow and develop. Blue light is responsible for flowering, budding, and the expansion of leaves."
"A good indicator of knowing whether your regular LED lights can serve as grow lights is by observing your plant’s physical growth.
If your plants aren’t receiving a sufficient amount of regular sunlight, they will grow tall and the leaves will be lighter in color. Once this happens, it’s time to take action and get some additional light."
"Weed plants have a bit different nature and requirements regarding sustainability and hence need a properly lighted environment for the better life.Weed plant need light as close to natural sunlight as possible."
"A light which has the majority of blue spectrum suits plants passing through the vegetation phase. This sort of light usually creates the purple effect in the grow space by delivering a dominant blue spectrum to the plants.
On the other hand, red colored spectrum is vital for plants growing through a flowering phase. However it’s good to use light with the majority of the blue band in its spectrum so that plants can produce resinous and heavyweight flowers at the time of harvest."
"One of the greatest benefits of using an LED light is that it does not create too much heat. Therefore, you can maintain an optimum temperature within the indoor grow area. Another benefit of using an LED grow lamp is that it can support the plants at all stages of growth.
As a LED grow lamp can create a defined light spectrum, it can help the plants grow healthier and faster. Plus, they use low energy and reduce the electricity bill."