There are Basically Two Types of Modern Induction or "Electrodeless" Lighting. 

1.  Electrode-less Fluorescent Discharge Lamps (EFDL) ,  “Electrode-less” Electromagnetic Induction, brilliantly bright Fluorescent lights on steroids, a “greenhouse” like diffused light source, which plants thrive with.
2.  Plasma Lighting System by LG (PLS), Microwave Induction Plasma Lighting System, intense, direct, penetrating, hard, sunlight like, a bright white appearing very Broad Bandwidth RGB light source.

With both Forms: Energy is transmitted into the tube by means of induction, in that it is induced from the exterior of the tube into the interior without the need of electrodes, in the interior of the tube the electrons are excited either through electromagnetic or microwave emissions.  Each method increases the effectiveness of the plasma reaction and the lack of electrodes greatly decreases the fall off of light source output over time.

With No Electrodes, Induction lighting is very intense and the output does not fall off quickly over a few months, as it does with all other currently popular, electrode based, indoor lighting, such as Fluorescent, HID, MH, HPS lighting.  Induction lights were first and primarily installed for the high efficiency and reliability, while producing intense light for a very long life time.

Recent Research has contributed to a greater understanding.  When a continuous spectrum is generated, similar to an Artificial Sun;  Red, Green and Blue photons provide for a more optimal light absorption due to efficient plant/light interception.  RGB colors combined are actually viewed as very white light, although all the colors of the visible and far red spectrum are present when viewed through a prism.

Induction Grow Light Spectrum

The Researched Approach? Use an induction system, select a fixture with a tube  possessing  a spectrum that is continuous, with no gaps, with the full “Rainbow” of “Sunshine” like colors, which extend over into the Far Red zones as well.  It has been documented that deficiencies in Red, Blue or Far Red can be compensated for by an increased Green light factor.  Sulphur Plasma, MWP, lighting fulfills the continuous requirement better than any.  The best of the Electromagnetic Induction, EI, lighting  has no gaps down to  the base line, but with very intense spikes of Red, Green and Blue.  The newest 12 Phosphor Blend produces a broad RGB Spectrum, dubbed as “Sunlight in a Box”, an additional 5% bandwidth @ the 620nm range, providing 95% Par Usable UV and IR Spectrum with an Added Red Phosphor Blend making them more suitable for efficient production from Clones through Flowering.

Measuring Plant Lighting

We measure visible light in Lumens, LUX, Lumens Per Watt or Foot-candles but are these measurements also adequate when measuring for a plants lighting levels? No.

While there is nothing wrong with knowing these measurements these are not the best measurements to tell us what is the best lamp for the our plants overall lighting needs.  A better way to measure plant lighting is to determine how much energy the lamp consumes and how much light actually makes it to the plant surfaces where both Photosynthesis and Photomorphogenesis occurs.

When measuring light QUANTITY for a plant we look to measure how many PHOTONS, (the minimum unit of energy involving light) are falling each second within a square meter. Photons are such a small unit of measurement that they are referred to as MICROMOLES OF PHOTONS or more often just MICROMOLES to describe a measurement of how many photons are arriving at a plants surface from the emitted light source. For reference 2000 micromoles would be a sunlight level measurement of light.

Of most value to the grower and his plant would be the number of photons being measured at the plant, per second, per square meter, within the PAR ranges of 380-720 nanometers. This value is then known as the PHOTOSYNTHETIC PHOTON FLUX (PPF) level that the lamp emits.

Meters that measure these (PPF) values are often referred to as QUANTUM METERS since a quantum is the amount of energy carried by a photon. These meters will provide entire spectrum measurements of the total number of photons per second values as well as measure the YIELD PHOTON FLUX (YPF) of the lamp which is as we’ve seen by the plants Photomorphogenesis requirements will assist the grower in identifying that the lamp has the proper PAR spectrum for maximum photosynthetic response at that stage of plant growth.

Another way growers like to measure light for plants is by PAR WATTS. What this refers to is how much light energy is available between the 380-720 nanometer ranges that the plant requires for Photosynthesis. What is extremely important to know the efficiency of the lamp being considered. Growers should be careful when considering these values and not to correlate higher PAR WATT values with more successful yields since with energy efficient lighting such as induction the PAR Watts per Square foot may measure 70% less then a HID and while still delivering micromoles in excess of the HID within the plants PPF and YPF requirements.

But is now held by many professional growers that plants may be utilizing light above 720 nanometers, a fuller spectrum will provide for the highest efficiency of absorption, and that higher levels of Green light will accommodate any deficiencies in those ranges.

When the most “efficient plant/light interception”, occurs, optimum absorption is achieved.  When the rainbow sun  spectrum is optimized, the plants unfurl and grow to a form more consistent with outdoor growth, leaf larger in size and number, thinner with more surface area and less bulk, plants thrive with fewer lumen and umole.  An old phrase says it best, “The proof is in the pudding”, or, results is all that matters!  Soon a new website from an group of growers will display images, and data, about these grow light sources.

The Grow Light with optimized spectral qualities and quantities, closest to Artificial Sunlight, will produce the highest yields, quality, the best flavors and  fragrance, with the fewest infestations, and with the less energy.  Greenhouse experiences suggest that dispersed light provides superior results over hard and uneven lighting, with EFDL the larger rectangular and round tubes and the fluorescence produce just such an effect.

 Electrode-less Fluorescent Discharge Lamps (EFDL)  have been around for quite some time.  Originally invented and Patented by Nicola Tesla in 1891.  In the modern age, these were initially introduced primarily for indoor and outdoor industrial and commercial lighting, much as HID, MH and HPS lighting were originally.

Based on Tesla’s well-known principles, light can be generated via a gas discharge through electromagnetic induction.  Electromagnetic transformers, which consist of rings with metal coils, create an electromagnetic field around a glass tube which contains a gas, using a high or low frequency that is generated by an electronic ballast.  The discharge path, induced by the coils, forms a closed loop causing acceleration or avalanche of free electrons, which collide with a solid amalgam of mercury atoms which excite the electrons. As the excited electrons from these atoms fall back from this higher energy state to a lower stable level, a plasma state, as they emit ultraviolet radiation. The UV radiation is converted to visible light as it passes through a tri-phosphor coating on the surface of the tube, which in this instance produces a strong RGB response.  All but 2-3% of the UV is converted, the small remaining UV is beneficial to plant growth.  The unusual shape of an induction lamp maximizes the efficiency of the fields that are generated.

How the EI Tube Works!

There are a number of Induction lights being sold under a variety names, much like Fluorescent and CFL lights the mix of phosphors the manufacturer uses in the tube can have widely differing results, the marketing name matters little, the results are what count!

Another Option:  The newest Phosphor Blend Light Spectrum has an additional 5% bandwidth @ 620nm range to improve Trichrome production, these can be used as a stand alone lights from Clones through Flowering, starting with these rather than T-5′s or CFL’s will provide a real jump start on the Vegetation cycle and will produce nicely finished buds.

Microwave Induction Sulphur Plasma Lighting is a more recent development.   Microwave Induction Plasma Lighting is like MH on steroids, these achieve optimum results for growth.  They are a bit low on Far Red to compete with Inda-Gro for finished bud results.  For flowering you may want to add some Red Booster lighting such as the WX-C-150 R Red Series LED.

Two types were invented in1990 by  invented by Michael Ury and tested and proven with Lee Anderson in 1994.  The difference between these and the Electromagnetic Induction lights is not simply the source of electron excitement.  The entire mechanism is quite different and varies by manufacturer.

With the compact Plasma Lighting System by LG®, a small inverter sends power to a Lightron® Magnetron which generates a Microwave transmission, this passes through a waveguide and slot onto a resonator mesh, this forms a strong electric field, initiating discharge of the inert gas in the bulb, the bulb heats up, the sulphur compound is vaporized, this vapor causes rapid ionization, generating a dense plasma which emits intense visible light.  The tube is quite small, compared to EI tubes, and extremely intense.

How the PLS by LG Works!

The Originators: SulphurPlasma.com have some very interesting things to say about  this exciting new “Sun on Earth” as they call it.  A Referenced Study compels one to see the huge benefits of this form of lighting with 1000 Watts of MWP out producing 2400 Watts of Metal Halide lighting, click on Biotronic Cucumbers – Read more to read the complete report.

The “Sun on Earth” factor allows these lights to produce more dry weight with less wattage, with less umoles and less lumen delivery, how is this?  The substantial difference may be due to more efficient plant/light interception , or simply put, Optimal  Light Absorption, with a continuous near AS Spectrum.

Typical Sulphur Plasma Light Output. Similar  to Autumn Noon Full Sun

A Netherlands Study: Sulphur Plasma /Quartz Halogen lamp combo grown Cucumbers produced 1.6 greater dry weight than those grown with HPS in 13 days.

With the MWP Spectrum, no Deficiency.

A low Red to Far Red or a low Blue to Red Spectrum ratio can induce an overall shade-type growth response in a wide range of species, characterized by general elongation, a response normally allowing plants to reach above near by plants.

Spectrum Deprived Conditions: Reduced growth and photosynthesis when plants are grown under only red light, (or too much red light?) can be can be reversed by adding sufficient green light to the spectrum.  The PLS lights have sufficient Green to compensate.  Informed by that article in: The Oxford Journal.  Read it in it’s entirety for greater understanding.

Getting the fullest spectrum that closest simulates a “Sun on Earth” will undoubtedly provide the best results with Indoor Horticulture.