by Nebula Haze
In our GWE growing community, a grower recently asked…
“I’m confused about all the different types of grow lights. What’s the difference between an LEC grow light and an Induction grow light? What about Plasma or CMH grow lights? They all look sort of similar to each other… and how are they different from LEDs?”
It’s crazy how fast things change! Back in the early 2000s, there were basically three types of grow lights available that worked for growing cannabis indoors. There were Fluorescent lights, Metal Halide lights and High Pressure Sodium (HPS) lights.
Then a few years later LED grow lights started gaining a lot of traction in the cannabis grow light market.
And now it seems like new types of grow lights are popping up on the market every day! You may have come across names like CMH, LEC, Induction and Plasma grow lights, and possibly more. It can get confusing with all the new terms being thrown around! So today I will explain exactly what each term means, and to expect from each type of grow light when it comes to growing marijuana.
Cannabis needs lots of light to produce good yields, but which type of grow light works best?
Today we’ll cover them all! Let’s start with the newer types of grow lights, and then I’ll compare and contrast with some of the more traditional grow light types!
New(er) Types of Cannabis Grow Lights
Ceramic Metal Halide (CMH)
This is an improved version of a Metal Halide grow light. The main difference is it uses a ceramic arc tube like an HPS grow light, which makes it more electrically efficient. This is why some CMH bulbs look like HPS bulbs until you get close!
Ceramic Metal Halide lights get good results in the cannabis flowering stage, much better than a standard Metal Halide does.
This makes it easier to spot problems on your plants, and it’s also just nice to be able to see and take pictures of your plants in full color!
In addition, Ceramic Metal Halides produce UV-B light like the sun, which may possibly increase THC and trichome production! However, Ceramic Metal Halide bulbs need a direct path to the plants for the best results. Reflectors and hoods without glass are preferred (more on that in a second) because glass blocks UV-B light from getting to your plants.
Light Emitting Ceramic (LEC)
Despite the somewhat confusing name, this type of grow light has nothing to do with LEDs!
“LEC” is a brand name (trademark) for a specific model of Ceramic Metal Halide grow light by the company Sun System. LEC stands for “Light Emitting Ceramic” and is a marketing term, not a new type of technology.
That’s why the term “LEC” is often used interchangeably with “CMH” in online grow light listings.
However, the form factor of the 315 LEC model by Sun System (which uses 315W) seems to be particularly effective at growing cannabis. Part of this may be because it was designed to stay cool even without glass, so plants are able to get full access to all the UV-B rays!
In initial testing, the 315 LEC grow light yields about 4-9 ounces per harvest on average, but some growers have written in and reportedly yielded much more! Please contact us if you want to share your results with LEC grow lights and possibly get featured on the website!
Increased trichome production under LEC Grow Lights
Magnetic Induction Grow Light
A Magnetic Induction grow light is basically an improved fluorescent grow light. Instead of using a filament, it uses induction to power the light. This causes the bulbs to last significantly longer than a regular fluorescent light because the filament doesn’t burn out over time.
They come in bigger sizes than regular fluorescents, but otherwise get similar yields considering the amount of electricity used. They definitely can’t compete with the more powerful lights!
Although Magnetic Induction grow lights actually work pretty well for growing cannabis, I don’t really recommend them because I believe they cost too much (and use too much electricity) for the yields you get. You will get better bang for your buck with many of the other types of grow lights!
Plasma Induction Grow Light
Instead of mimicking fluorescents, this type of induction light uses microwave radiation and excited sulfur plasma to generate light. This produces a greenish white light that looks beautiful to people, but unfortunately doesn’t work that great for growing cannabis.
Even worse, Plasma grow lights cause RFI interference which can alert someone to your grow! For security reasons alone, I highly recommend avoiding Plasma Induction grow lights Basically any other type of grow light is better!
So how do these compare to more “traditional” grow lights? Let’s do a quick breakdown…
More “Traditional” Grow Lights
Fluorescent Grow Lights (CFLs & T5s)
This group includes CFLs and T5s and is one of the most common types of grow light for hobbyist growers of all types of plants. CFLs can be found anywhere, including gas stations, and T5s can be found at most stores with a garden section (like Home Depot or Walmart).
Outside the cannabis world, fluorescents are often used for starting seedlings, as well as for growing various flowers, herbs and vegetables. They are a little underpowered for growing marijuana, but offer a great spectrum and can actually get some pretty decent results when combined with diligent plant training.
A Metal Halide (MH) is a very powerful grow light that gives off a bluish white light. It is often used for the cannabis vegetative stage and produces fast, healthy green vegetative growth.
The Metal Halide is Part 1 of the “golden standard” of grow lights, and is the most common grow light used by commercial growers in the vegetative stage.
High Pressure Sodium (HPS)
A High Pressure Sodium (HPS) lamp is a very powerful grow light that gives off a harsh yellow light. It is often used during the cannabis flowering stage because its particular light spectrum stimulates bud production. HPS is also one of the most efficient types of grow lights available on the market, and produces amazing bud growth!
Because of these factors, HPS lights get some of the best cannabis yields of any grow light. That’s why HPS is Part 2 of the “golden standard” of grow lights!
A combination of Metal Halide and HPS grow lights has been used by commercial growers for decades, and even though new types of light are on the market, MH/HPS are still by far the most common type of grow light for those looking to yield large amounts of bud. But that may change over the next few years as grow light technology improves!
LED Grow Light
You’ve probably seen these before! An LED lamp is basically a panel containing a bunch of tiny LED diodes. Although there are some full spectrum LED grow lights these days, the light from most LED models usually looks purple.
Although the LEDs from 10 years ago weren’t that great for growing marijuana, modern LED grow lights generally get yields almost as good as HPS grow lights!
- Ceramic Metal Halide (CMH) – Improved version of a Metal Halide grow light that uses a ceramic arc tube, which makes it more efficient. CMH grow lights can be used in both the vegetative and flowering stage.
- LEC Grow Light – LEC stands for “Light Emitting Ceramic” and refers to a Ceramic Metal Halide grow light produced by the company Sun System. In other words, “LEC” is a marketing name for a CMH light in a specific fixture, not a new type of grow light technology.
- Magnetic Induction – Basically a big, glorified fluorescent light. Although they last a long time and work well for growing cannabis, they aren’t much more efficient than regular fluorescent grow lights.
- Plasma Induction – An induction light that produces a greenish light that looks nice but doesn’t get great results with growing cannabis. Even worse, they create RFI interference which is not good for security! Avoid Plasma Induction lights! Basically any other type of grow light is better for growing cannabis indoors.
Compare to More Traditional Grow Lights
- Fluorescents (CFls & T5s) – Cheap to get started, very effective growing spectrum, but a little underpowered
- Metal Halide (MH) – Powerful light most commonly used for the vegetative stage
- High Pressure Sodium (HPS) – Powerful light most commonly used for the flowering stage. HPS lights are considered to have some of the best yields of any grow light. Together, MH and HPS are currently the most popular grow lights used by commercial growers.
- LED Grow Light – These light panels house several small LED diodes and usually produce purple light (though some newer LEDs produce white light). The technology for LEDs has been improving quite a bit over the last decade, and they now get yields that are nearly as high as HPS grow lights.
I hope that helps clear up some of the confusion about all the different types of cannabis grow lights! But if you’re interested in learning more, read an even more detailed breakdown of cannabis grow lights!