LED Grow Lights Review

Before LED Grow lights, came LED lights. In 1907 an inventor who worked for Marconi, a large hi-tech electronics company, discovered electroluminescence and the first light emitting diode-based device was made from a Silicon Carbide and a cat’s whisker, but not much other use was found for this phenomenon. Much later in 1962, a GEC experimenter found he could maintain constant electroluminescence in visible wavelengths and had come across a cheap way of using semiconductors (diodes, which create a kind of one way street for electricity) to emit light just like a conventional light bulb could, the only drawback was that they had a limited output power. By 1976 it was possible to make brighter versions of these “Light Emitting Diodes” commonly called LED’s and all types of devices started incorporating them for one reason or another. Mainly used as indicator lights in electronic items in the earlier years of mass production, LED technology has progressed somewhat and these days a single LED can not only be very bright indeed, their output can be also controlled in ways that were previously impossible. One of the major advances is not just in the brightness of the LED’s or the low power consumption of these devices, the actual light spectrum can now be controlled in a constructive way such that the photosynthesis of plants can be optimized by providing exactly the light spectrums that they need at the appropriate phase of their development. This is one of the main reasons that LED Grow lights are becoming more and more popular as their price becomes more affordable.

Plants use light to convert starch into energy via the well-known process of photosynthesis. Although a fairly complex chemical process, it is not difficult to see that plants do better in some types of light and not so well in others. This is because during the phases of a plant’s growth and reproductive cycles, the plant requires a different combination of light wavelengths at different periods of the growth and reproductive cycle to develop properly. In nature this variety of wavelengths are present in the sun and surprisingly at different times of the year we get different colored sunlight. Readers may have noticed that in the summer that the sun looks more orange and the sky is more of a yellow hue compared to the middle of winter when even if there is no snow, everything looks bluer (and colder). This is because our seasons are determined by the fact that our orbit around the sun is not a proper circular orbit, but elliptical. This means we are further away from the sun at certain times of the year, dimming its intensity. Through the seasons, refraction of the sun’s light through the atmosphere gives us a sunset – i.e. the sun turns more yellow/orange/red at night. In the summer the sun is higher in the sky so the sunset takes longer than in the winter, so for more hours of the day, the earth is exposed to wavelengths at the red end of the spectrum. It is the opposite in the winter, so the sunsets (red light) takes up less time and the blue sky dominates the percentage of daylight. The air density is also different in hotter seasons so the refraction of sunlight is red shifted rather than the blue-shift that cold air gives us in the winter.

When a seedling emerges, the dominant daylight wavelength (Blue=Winter+Spring becomes Orange/Red=Summer+Autumn) will determine what the plant will do next. A plant born in the spring will want to grow as tall or wide or big as possible to compete in the wild and uses the blue wavelengths to achieve optimal growth through photosynthetic energy production in its early life. When the wavelengths start to change to the red spectrum , as when summer progresses and the fall arrives, plants have to flower to reproduce so have adjusted their physiology through genetic natural selection to utilize the red frequencies of light to power the flowering process which has to take place before winter starts. So the cycle of an annual plant is that of growing fast during high intensity blue wavelength lights (the blue/white type of light a Metal Halide (MH) bulb gives off) and flowering heavily during the redder wavelengths (the type of light a High Pressure Sodium (HPS) bulb emits). It is the ability of LED growing lights to emit specific wavelengths of light which include both blue and red light that make them so appealing to plant growers.

This means that growing under artificial lighting is not as simple as putting up a single bright light and hoping it will suffice. The sun has a massive luminosity at all wavelengths and most of the energy is not used by a typical plant outdoors. An indoor grower obviously cannot recreate the brightness of the sun, but emulating its spectral behavior can reap huge benefits when it comes to encouraging successful growth and flowering phases, this is why indoor growers using conventional (high cost, low efficiency, heat generating MH/HPS ) often grow in stages with different bulbs. Whichever combination is used, the MH/HPS systems are expensive to run as a lot of heat energy is wasted and light is emitted at wavelengths that the plants cannot use to photosynthesize, so efficiency is below 30% with conventional grow lights.

The great news is that recently LED grow lamps have not only been developed to be bright enough to offer sufficient light energy to promote healthy photosynthesis, today’s control systems and LED technology achieve the same great energy efficiency as the LED’s we all know, (10% of the energy used by older MH/HPS grow- lights) but can have the output light wavelength controlled simply so that they are able to emulate in real time the correct light output wavelengths for whatever growth and flowering cycle the grower has chosen.

This simply means that a grower can completely control the growth and flowering cycle of a plant by adjusting both the wavelength of light available for photosynthesis and the day-length; the exact number of hours exposure per day is another controlling factor in the flowering cycle.

The latest LED grow lights respond to a programmable controller unit and emit differing exposure times and limited wavebands (range of wavelengths) that encourage the optimum growth for the plant. For a plant with a short and fast growth cycle this might mean exposure to the blue wavelengths (where previously a power-hungry MH bulb would be used) 24 hours a day for as long as it takes the plant to reach the desired flowering height. In effect the LED system burns blue for 24 hours a day 7 days a week until this desired height is reached. At this point, the LED control unit can alter the light emission toward the red spectrum and switching to an exposure time congruent with autumn, such as 14 hours of light or less, will ensure the plant swings fully into a flowering stage and will not grow in a vegetative way any further (no more significant leaves are grown and the larger leaves are sacrificed to feed the flowers as their bloom matures, the plant puts all its energy into its flowers. Controlling the rate of day length shortening (i.e. going from 15 hours per day down to 12 hours per day in increments) can control the length of time taken to flower. This is not the exact mechanism in all plants but is a common feature of plant physiology. Controllability like this does not imply you can just leave indoor gardens to themselves. They must still be carefully tended, fed, kept clear of parasites and insects and above all, given the best possible conditions for photosynthesis and your grow lamp system is integral to that aim. Having a lighting system that is optimal in spectrum and programmable in nature should leave growers more time to concentrate on other aspects of caring for their indoor garden!

There are alternatives to LED growing lights such as the MH and HPS lighting but they emit a great deal of radiant heat, are a fire risk and above all, they cost a lot to run as they are power hungry and inefficient. The best LED grow lights in comparison offer instantly controllable light with low heat radiation, with the light energy focused within the perfect band of wavelengths for optimal plant growth. LED grow lamps offering the same luminosity use about 20% of the power consumed by MH/HPS bulbs.

A recent LED grow light review found that Fluorescent grow lights offer similar cost savings as LED grow light systems but their luminosity/intensity is not close to that of modern LED systems and are really only suitable for raising seedlings or plants with long growth cycles as the vegetative growth stages will be slow. Young plants striving for maturity need more light energy to grow quickly, so they need a certain amount of brightness to achieve those fast growth rates.

Using LED grow lights avoids the great heat buildup associated with MH/HPS lamps which may not just be dangerous but can often scorch the plants when used in enclosed areas. LED lamps emit only a modest amount of the energy they consume as heat and are mostly only at a safe “warm-to-the-touch” temperature whilst operating. Simply the most effective way to grow indoor plants in the 21st century, LED grow lamps may seem like a heavy investment but they actually compare well to traditional ballast lamps. This also means that LED grow lights can be placed closer to the plants further improving photosynthetic performance.

When it comes to indoor plant growing techniques, you will often find that the big horticulturists set the trends and smaller home gardeners follow suit, they don't come much bigger than weed growers and it has been recently noted that they are increasingly using led lights for growing cannibis, as they find that the benefits of lower overheads heavily outweigh the initial purchase cost of the LED grow panels.

LED grow light systems are eco-friendly and work great with hydroponics because there is no heat problem and no associated increase in humidity to have to deal with. This would normally mean more electricity expense using dehumidifiers remove the moisture from the air created by the hot Halide/Sodium bulbs. Obviating this requirement further reduces the overall energy demand for indoor growing and so the bill to power an indoor LED powered growing operation is even lower still in comparison to outdated methods like the MH/HPS lamps and the carbon footprint left behind is smaller as a result too! Even though fluorescent tubes are cost effective to run, they have a short life, are not very bright in the spectrums that matter and are not very eco-friendly to dispose of either!

Sheer robustness and durability, low running cost, eco-friendliness, zero maintenance, safe to use and multi-waveband operation, these 21st century devices live up to every claim they make – anyone looking to install an indoor growing system should choose an LED system to get the best value and performance for their money. They beat other grow light solutions in every aspect of price, quality, safety and convenience and above all they produce great quality indoor plants!

The life of LED bulbs runs into the 10’s of thousands of hours compared to the thousand hours of MH/HPS bulbs, whose light quality and waveband coverage changes with age. The bulbs of the MH/HPS are expensive too and unlike the multi-LED lamps are single filament and when they fail they are $50 for a cheap led grow light bulb and up to $300 for specialist spectrum bulbs! The electrical ballasts (power supplies) required to balance the power to these thirsty bulbs alone cost $150 per ballast.

A single square yard with a 600Watt MH/HPS system would require 2 bulbs, ballast and 5X the electricity to run as an LED but approximately the same outlay!

MH/HPS : Proper spectral grow bulbs (2 required) $150 + $150 for the ballast approx. $300 outlay.

LED grow light system : Basic multi-wavelength controllable LED + panel approx. $300 outlay.

Both are prices for the absolute basic equipment and rise accordingly according to the sophistication of the grow light system. Although the LED equivalent of a 600W MH/HPS bulb is only 120W for the same square yard, but at one fifth of the running cost. The energy cost can be a real issue because a 600 Watt bulb might cost $25 per week ($1300 per year) in electricity, compared to a running cost of $5 per week for the same coverage by LED systems ($260 per year).

A grow room with 12 plants might cost $5200 per annum in electricity (assuming 4 conventional lamps and an intensive grow system) compared to just $1040 using LEDS! That’s a significant amount of money that can be saved by using the latest technology.