The Lowdown on
Some have expressed doubts
about the effectiveness of LED Grow Lighting, we agree, the earlier
generations of LED Grow Lights have been disappointing, we hope to have a discussion that
shed some light on the subject. This is what I have gleaned thus far, you are welcomed to share
We suggest that at this time LED lighting is best used as supplemental
Greenhouse lighting and as supplemental lighting for indoor use to add
spectrum for better results with particular species.
A few have reported that LED
Grow lighting alone does not produce as prolific vegetative growth as they
get with Sunlight or HID grow light sources, but, reference to controlled studies by NASA indicate that is not true, that in fact 80/20% Red/Blue LED Grow
Lighting outperformed HID Lights, and neither source did quite as well as natural
light, see the chart below. There are many variable beyond light
alone, but the quality of light is key.
In real world use the LED does a pretty adequate
job with Veg states, but does not provide optimal results with Flower. You
will need a good deal more light than most manufacturers suggest.
One of the biggest problems with LED Grow
Lighting is the failure rate, they often have power supply issues or burn
out LEDs. This is has been a huge challenge, to find a reliable manufacturer
that also build a product that deliver appropriate spectrum. We have
narrowed our choice down to only a couple.
Missing Spectrum, Unraveling the code:
It appears that some manufacturers have selected nm ranges that when
combined provide a very nice and full spectrum, yet one has to ask, can the
spectrum be truly full without green and/or white light? The addition
of White LEDs (our manufacture added 3500K white modules) makes for a
very full spectrum, with small amounts of numerous green and white
gradations, the resulting waveform closely matches that of the absorptive
spectrum of green plants, but not as wide as Inda-Gro Lights or PLS.
Current "Future" Applications of Horticultural
LED Lighting, Specialized Supplemental Lighting: The experts tell me these
lights, Flower Initiator, will not be supplemental, but an essential light.
"The Flower Initiator"
Far RED LED Flood lights. Users
have reported accelerated bud initiation. You might "experiment" with this
light on a separate timer for 1 Hour prior to lights out then for 10-15 minutes
thereafter, as a phytochrome trigger, to hasten the instigation on Budding, reducing the
Phytochrome switch period from 2 hours to 10-15 minutes. Other optional
experiments are suggested on the order page.
Not all LED Grow Lights are created equal,
quality might vary and our "state of the art" commercial products yield
greater intensity than LED Grow Lights did in the past, yet we still suggest
they are best for supplemental usage for spectrum tweaking. Our lights pass
the reliability test with flying colors.
Heat and Cold:
It has been suggested that, in some cases, a growing environment may have
been too hot or too cold to make the plants respond with Spring like growth.
In colder climates the lack of heat theory makes sense, it is well known that waste heat is one
thing produced in excess with HID lights and that LED Lighting produces less heat. Perhaps a supplement of
FAR RED or Spectrum or
retaining some HID Light for heat and additional light might do the trick.
Although a well insulated air tight, temperature and humidity controlled space should
receive enough heat from LED Grow lights, they do produce waste heat.
With all methods excessive heat
also can greatly reduce productivity.
It is generally known that too
much heat is generated by HID lamps, Fans and Movers are employed.
Movers are not required with Led Grow Lights, fans are needed only when the
environment itself generates excessive heat, but the plants like moving air, the Led Grow Lights produce
what is generally just sufficient heat and is easily dissipated by built
in cooling fans.
The truly important aspect of
artificial lighting is the concept of Action Spectrum, or the amounts and
colors of light that are absorbed and used by chlorophyll producing plants.
the free encyclopedia:
An action spectrum is the rate of a
physiological activity plotted against
light. It shows
light is most
effectively used in a specific
reactants are able
to use specific wavelengths of light more effectively to complete their
reactions. For example,
chlorophyll is much
more efficient at using the red and blue
spectrums of light
to carry out
Therefore, the action spectrum graph would show spikes above the
wavelengths representing the colors
action spectrum graph for chlorophyll production is overlaid upon the
color wavelength spectrum, the corresponding spectrums generated by
standard 80% Red/ 20% Blue LED Grow Lights and standard HID (Metal Halide)
Grow Lights are also overlaid.
One can observe that the
standard HID Light produces light spectrums that are insufficient in the
blue and red spectrum and excessive in the yellow-orange spectrum as well
as in the yellow and green spectrum, where very little is absorbed.
Halide lights compensate for this by producing bulk amounts in all
spectrums they produce.
LED Grow Lights, used for this example, more
closely parallel the exact wavelength requirements for chlorophyll
producing plants, although most produce an excess of Red and
are somewhat deficient in Blue light. By generating a light spectrum
that most closely matches the Action Spectrum yields the greatest results
with the least amount of energy expended.
manufacture provides for a superior product, made with a better spectrum
matching and better balanced ratio options of BLUE, RED, Orange, Deep RED
and White light.
You will be convinced by the improved health and productivity in all
phases used as supplemental lighting.
The Standard Spectrum light
3500K White to fill in the
requirements in the trough in the yellow and green zones.
200 - 280 nm UVC ultraviolet
range which is generally harmful to plants. LEDs in this spectrum are
non-existent or very expensive.
280 - 315 nm Includes harmful
UVB ultraviolet light which causes plants colors to fade. This range is
useful for Trichrome production, believed to be due to positive stress.
315 - 380 nm UVA ultraviolet light which is neither harmful nor beneficial
to most plants.
380 - 400 nm Start of visible
light spectrum. Process of chlorophyll absorption begins. UV protected
plastics ideally block out any light below this range.
400 - 520 nm The violet, blue,
and green bands. Peak absorption by chlorophyll occurs, and a strong
influence on photosynthesis. (promotes vegetative growth)
520 - 610 nm The green,
yellow, and orange bands and has less absorption by pigments.
610 - 720 nm The red band.
Large amount of absorption by chlorophyll occurs, and most significant
influence on photosynthesis. (promotes flowering and budding)
In Sunlight the ratio of red
(660nm) to far red (730nm) is about 1.2:1
Interestingly Phytochrome Pfr is activated by 660nm and Pr is activated by
720 - 1000 nm Little
absorption by Chlorophyll here, Phytochrome responds in the 720range.
Flowering and germination is influenced. Near this range and higher end of
the band is the Infrared spectrum, which is mostly heat and promotes
elongation or negatively affect water absorption/transpiration.
Many plant pigments have dual wavelength peaks that can be activated with
LED light combinations:
Beta-carotene 450nm 480-485nm
chlorophyll a 430nm 662nm dual
chlorophyll b 453nm 642nm dual
phycoerythrin 590nm single
phycocyanin 625nm single peak
670nm and 700nm for the
- Light Emitting Diode:
The LED is similar to a
transistor in that it is a solid state device, which work so efficiently as to
produce very little in the way of waste heat.
LED lights will operate up to 60,000
hours before dropping below 75% of initial production, HID
lamps loose 20% of productivity after the initial burn-in period. While well dispersed the
LED light is directional, unlike 360° conventional
lighting, which adds 46% more useable Lumens.
• 30%~40% Energy-saving over HID
• Solid State, High Shock/Vibration Resistant
• Work without ballast
• No RF Interference
• No Flickering
• Instant Soft-start
• Minimum Maintenance Costs
• Produce Little Heat
• Reduced Risk of Fire Hazard
• No Mercury and other Hazardous Materials, fully RoHS-Compliant.
Today's advanced LED
Grow Lights will pay for themselves in energy savings over their very long lives
and will repay in multiples on the quarterly replacement cost of HID bulbs.
Astroculture Plant Growth
that the Red/ Blue ratio used in most commercial LED Grow Lights,
were used in these studies. The solution used in Astroculture is lighting
provided by high intensity light emitting diodes (LEDs). To make the
lighting as energy-efficient as possible, only the wavelengths needed by the
plants are incorporated into the LED light caps. Plants require light at
about 670 nm (red) for photosynthesis and a small amount at about 470 nm
(blue) for development and for proper orientation in the near absence of
According to a
University of Minnesota
LED lights would have the
potential to greatly increase energy use efficiency of commercial greenhouse
lighting, thereby passing on significant savings to growers and consumers.
While the initial investment in LED lighting is higher ($1,760) than HID
lamps ($400), the cost-savings over a 7-year period are $2,291 due to their
lower energy use and bulb longevity. NOTE: Costs for LED Lighting have
gone down, while energy costs has increased since this study was released.
Some results of this study in the two Charts below.
Natural Light - LED - HID
The above Study of LED Grow
Lights, and the manufacturer claim found below,
suggests that perhaps additional gains may be had with an increase of the
Blue color spectrum during the growth phase, if you seek denser growth.
The University study indicates that Red light only produced plants with
greater distances between branch internodes and softer, less dense, growth,
whereas, the Blue alone tests produced plants with less space between the
internodes and denser, stiffer leaf growth.
One Manufacturer claims that:
"The most important benefit to LED light is that you have full control over
the wave lengths of Red and
Blue light ! The amounts of Red and Blue light
can be precisely controlled. Light can be placed exactly
where you need it
most. I have placed a Red LED right against the surface of many plants
the areas most likely to produce a flower including
orchids, and few days later flower buds started to form! Amazing!!! The
level of growth manipulation and control that LEDs can offer the grower are
only just now
being barely explored. We have manipulated tiny seedlings with
excess red light and in just weeks watched
them burst into flowers. We have
controlled annuals with excess Blue light into thinking summer was never
going end and made the last for many years while turning them into
monstrously large plants! LED growing
is in its initiatory period and much
more will be learned in the exciting years to come!"
We are convinced
that this manufacturer is onto something!
Chlorophylls and Carotenoids
Two types of chlorophyll are found in plants and the green algae.
* chlorophyll a and
* chlorophyll b
Both chlorophylls absorb light most strongly in the red and violet parts of the
spectrum. Green light is absorbed poorly. Thus when white light shines on
chlorophyll-containing structures like leaves, green light is transmitted and
reflected and the structures appear green.
In the chloroplast, both types are associated with integral membrane proteins in
the thylakoid membrane.
Chloroplasts also contain carotenoids. These are also pigments with colors
ranging from red to yellow.
Carotenoids absorb light most strongly in the blue portion of the spectrum. They
thus enable the chloroplast to trap are larger fraction of the radiant energy
falling on it.
Carotenoids are often the major pigments in flowers and fruits. The red of a
ripe tomato and the orange of a carrot are produced by their carotenoids.
In leaves, the carotenoids are usually masked by the chlorophylls. In the
autumn, as the quantity of chlorophyll in the leaf declines, the carotenoids
become visible and produce the yellows and reds of autumn foliage.
Seasonal Color Theory:
produces a full but seasonally shifting spectrum of light, during the long
when the sun is high overhead the sunlight is of longer duration,
greater intensity and contains a higher
content of Blue light, HID lamps color
rendering index does not mimic
this season's index closely enough, HID lamps produce largely Yellow light which
is not very useful to growth and harmful
UV and IR. levels, about 25% of the energy is useful. In greenhouses and outdoors, the long lighting
period, the intensity and color content all
effect the amount of growth
experienced during the summertime.
During the late
summer, fall and winter, as the sun appears to become closer to the horizon, the
through the atmosphere at a progressively sharper angle, through
thicker air, and is filtered by this lens to have
a higher content of Red.
This high Red content is what the LED Grow lighting is meant to supplement, to
enhance this beyond the natural state and cause a lengthened window to achieve
larger and more prolific blooms.
It may be inferred that the higher Blue light content of the
lengthened hours of summer might be more closely simulated with the addition of
more supplemental Blue LED lighting during the vegetative growth period, this is
known as "Blue Boosting". But one must ask, "Is it really necessary with
highest quality lights? The answer, your real world experience with your
particular species will teach you what they prefer.
Our New Standard LED Grow Lights, when used alone, produce small compact plants that
tend to bolt before and upon entering an extended bloom cycle. Our
manufacturer suggest their LED Grow Lighting is for for supplemental indoor use, as
greenhouse supplemental lighting to enhance and lengthen the Bloom cycle.
Our experience is that these High Quality Standard lights really work, and work
well particularly as supplemental light for better spectrum control.
We offer 150 Watt100%
RED and BLUE Booster Lights for those seeking spectrum and intensity adjustability to mimic seasonal
variations. It is great a choice for the
Designers and manufacturers world wide have,
until recently, blindly accepted the conclusions of limited testing in low
gravity conditions of NASA LED Grow Light studies, and promote lights using a
80% Red and 20% Blue ratio. Our observations and testing prove greater
effectiveness near a more optimal ratio such as the one provided by our
manufacturer supplemental lighting.
The Bottom Line:
LED Grow Lighting will save
considerable amounts of Energy and are better for the environment in multiple
ways, our improved consideration of appropriate wavelengths and ratios provide
superior products that will assure the maximum benefits for your critical projects. Research has led us,
our manufacturer, to provide supplemental LED lighting that more closely match the spectrums and
ratios appropriate for healthy plant production, tests prove this out.
They are great for adding
Plasma lighting or further tweaking with standard commercial induction lighting,
those that are not purpose built.
Inda-Gro EDFL Lights are the first
and only purpose built Induction lighting system anywhere that does not require
Using the most energy efficient
lighting is crucial to keeping your costs reduced over time, as energy prices
inexorably edge up, make sure you consider all options
before making such costly investments.