What Are LEC Grow Lights and Should I Use Them?

CMH or Ceramic Metal Halide, now also known as ‘LEC’ grow lights, are a new technology that is slowly gaining support around the world with cannabis growers. Increasing numbers of farmers are adopting them as word gets around about their unique daytime-like white light along with larger yields than under LED or HPS. Several large grow operations in Oregon have adopted these type of lights so people are starting to take notice.


What are LEC grow lights?

LEC stands for light emitting ceramic. These lights work in a very similar way to metal halide (MH), apart from the fact that they utilise a ceramic arc tube instead of quartz and they run at a much greater pressure.


Sometimes referred to as ‘ceramic metal halides’ they give much higher performance than a standard metal halide bulb offering a spectrum of light very similar to sunlight.


The light created by LEC is about as natural a light as you can get without shelling out thousands on plasma lights. One can not say this of LEDs or HPS.


For one thing, this makes keeping an eye on your grow much easier. You can spot deficiencies and the like without having to turn lights on or off. It’s also a heck of a lot stealthier than a bright pink or purple LED which needs substantial cover in order to disguise its bright light when switched on.


LEC grow lights are able to produce UV-B rays (like the actual sun) something that according to some reports may increase trichome production, but no scientific studies have been carried out on this yet. For this reason you shouldn’t stare directly into LEC lights; they should be treated with care as if they are emitting suns rays.


Can I use LEC throughout the grow?

Yes you can. Like LEDs, LEC can be used from seed to flower, making them an attractive option for a simple grow.


Many LECs also come with a ballast, so it’s literally a case of ‘plug and play’ with these lights. They also last longer than traditional halide or HPS growing bulbs. You can buy bulbs on their own that need to be hooked up to a ballast like a HPS.

Will I get higher yields with LEC grow lights?

Obviously, this depends on what lights you are running now. It would appear that LECs are out-performing metal halide and LED grow lights, and in some cases HPS, when it comes to flowering your cannabis plants.


One grower reviewing on Youtube said:


“I have observed fast and compact vegetative growth and awesome tastes and aromas, and my leafy crops too. However, I think this grow light could play an important role for growers producing flowering and fruiting crops too. After all, a dynamic vegetative state provides the essential scaffolding for any future bumper harvest.”

Another found that the final product had much better looking crystals, if that can be used as a guide, when the LEC grow light was put up against a HPS, and the bud growth also seems to be more prolific.

What are the best CMH bulbs to use?

In tests done by Growershouse, several different types of CMH were tested against each other.


Light readings of UV light intensity at 24” were taken and the best performing bulb was the Ushio 3000K, followed by both the MaxPar 4200L and the SunPulse 3200K. They beat bulbs from Philips and Solistek for overall UV light intensity.


However, in more detailed tests measuring light intensity at differing points from the bulb and combining overall scores, the Philips Mastercolour 3100K was way ahead of the rest of the bulbs.


Where can I get these in the UK?

Philips or other brands of CMH bulbs are available on Amazon or from your local gardening shop. You may need to get a ballast (per supply) and reflector unless you buy the bulb as an all in one system.