Eco-friendly Horticultural Lighting: The Future is Here

We are in the midst of an ecological movement stemming from a heightened sense of awareness that our current path of over-consumption is unsustainable and detrimental to our planet.

This global movement affects every industry and technology and challenges manufacturers to not only produce ‘green’ products but to do so in a manner that is eco-friendly.

To this end the horticultural industry has been making significant progress in developing new, energy-efficient light fixtures, its main goals being to produce light technologies that consume less energy, produce more photosynthetically active radiation (PAR) and contain fewer hazardous materials.

Products designed under this multifaceted approach will reduce pollution created as a byproduct of electricity production—most of the CO2 emissions in the United States are caused by the generation of electricity—and reduce harmful waste that eventually contaminates our soil and water.

LEDs vs. Induction Lighting Technology in the Growroom

Two lighting technologies stand out in my mind as being ‘the future’ of eco-friendly horticultural lighting: LEDs and induction lighting technologies.

Neither technology is new; in fact, induction lighting has been around since the 1890s—although the more advanced sulfur-plasma technology was developed in the 1990s—and LEDs were introduced in the 1960s.

The expanded use of these forms of lighting in future horticultural applications will be due to advancements we’re now beginning to make in our understanding of plant physiology, combined with improvements in production methods that will lower costs.

LEDs

Light-emitting diode or LED technology is gaining huge popularity in the horticultural industry. This is due mainly to NASA, which continues to conduct plant-growth experiments under LED lighting.

LEDs show immense potential as horticultural lighting fixtures due to low energy consumption, cool operation and the capability to customize their spectral output to emit the specific wavelengths most usable by plants.

All of these factors—combined with their longevity and durability—make LEDs the most viable eco-friendly solution for horticultural lighting. LEDs are also solid state devices that do not depreciate in their output of usable plant energy (PAR) like their HID and fluorescent counterparts—in fact, LEDs can be used for horticulture for up to 10 years without a substantial decline in PAR output.

LEDs emit light in a very unique and efficient way that produces much less heat than standard lighting fixtures.

In most indoor gardens heat is considered waste and is generally removed by a fan or air conditioner, but LEDs are able to reduce the energy consumption associated with the removal of excess heat by not producing so much in the first place.

LEDs contain no mercury, but due to the presence of other compounds these bulbs should still be recycled after their long lifespan.

Induction lighting

Induction lighting illuminates without the use of an electrode, instead using an electromagnetic field to stimulate compounds found within the bulb.

Electrodes are generally the limiting factor in lamp life and efficiency, so it makes sense that induction lighting would be a great choice for a long-lasting, efficient lighting source.

There are also certain higher-efficiency substances that can be used in electrode-less lamps that would react poorly with the metal electrodes used in standard lamps.

For horticultural purposes, there are two types of induction lighting currently showing the most potential: sulfur-plasma lamps and fluorescent magnetic induction lamps.

Sulfur-plasma

Sulfur-plasma lamps consist of a small fused quartz sphere (or bulb) containing a mixture of argon gas and sulfur powder. The sulfur and argon gas are excited by microwaves produced by a magnetron—which heats the sulfur, causing it to illuminate.

What makes sulfur-plasma so exciting for the horticultural industry is the truly full-spectrum output it can emit and its long lifespan. A sulfur-plasma bulb is rated for 60,000 hours (five to seven years of continuous use) with virtually no depreciation of photosynthetically active radiation.

Although sulfur-plasma lamps are realistically years away from practical use in horticultural applications, their long life—combined with the absence of mercury and other hazardous waste—makes them a strong candidate to be a leading eco-friendly choice for the future.

Magnetic induction fluorescent

As with standard fluorescent lighting, magnetic induction fluorescents use electricity to excite mercury vapor, which excites phosphors—thus producing light. The difference lies in the way the mercury vapor is excited.

Magnetic induction fluorescents, like their name suggests, use electromagnetic induction to transfer energy through the glass envelope of the bulb to excite the mercury within. The absence of any electrode in the fluorescent light tube creates a multitude of ecologically friendly benefits.

Electrodes found in standard fluorescents create an escape route for the gases in the tube—the escape of these gases decreases light output and requires more mercury to be used. Induction fluorescents require half the mercury content of comparable standard fluorescents, making them a much better choice for the environment.

Although standard fluorescents need to be replaced about once a year because the usable light energy for plants diminishes as the bulb’s internal compounds break down or escape, magnetic induction fluorescents can be used continuously for five to seven years with little or no reduction in PAR.

It should also be noted that the mercury used in induction lighting is in a solid form, which reduces contamination in case of accidental breakage and makes full recovery during recycling simpler.

Magnetic induction fluorescents—just like LEDs—also produce much less heat than high-intensity discharge lighting, which reduces overall energy consumption.

Proper disposal of fluorescents, metal halides and high-pressure sodiums

Many growers do not realize they can reduce the amount of toxic material entering our soil and water by simply recycling (versus throwing out) their old bulbs.

Almost every recycling facility accepts bulbs and will actually salvage some of the components and compounds that can be reused.

Contact your local recycling center to find out the proper procedures for your area—recycling unwanted bulbs is a useful contribution to our planet’s bright future.