What are CMH/LEC lamps?
CMH (ceramic metal-halide) lamps are basically the next generation of MH (metal halide) lamps. The main difference lies in the tube: while MH lamps use quartz, CMH lamps use ceramic. Ceramic tubes offer multiple advantages because this material withstands very high temperatures and their light spectrum is far better than the one produced by HID lamps. This is down to the gas inside the quartz tube that lowers the temperature but can have a negative impact on the cultivation. The light spectrum produced by ceramic tubes is very similar to the sun, that is, optimal for the development of our plants during their entire life cycle.
We cannot forget that, when CMH lamps are bought in parts, it's very important to make sure it's a low-frequency ballast, either magnetic or electronic. Nowadays there are two CMH lamp types available: full spectrum 3100 K lamps, suited for both the flowering and vegetative phases, and blue spectrum 4200 K lamps, mostly used for the growth stage. CMH lamps are increasingly used in the street but also in industrial lighting.
Advantages of CMH/LEC lamps
One of the main benefits of CMH lamps is that they produce an optimal light spectrum for our plants' growth compared to other HID lamps available on the market.
Their being so efficient means that using a low potency CMH lamp will be more or less like using a top-potency HPS lamp. This obviously brings about significant energy conservation benefits plus a reduction in environmental pollution. For instance, a 315 W CMH lamp will yield the same results as a 600 W HPS lamp. But the benefits don't end there. Since they generate less heat, the ventilation and air conditioning systems don't have to be working at full power all the time, leading to even more savings. Not only are they better suited to the needs of our indoor cannabis plants but their useful life is about 50 % longer than traditional MH lamps'. They're also twice more efficient in terms of lumens and some 20 % more efficient in terms of PAR. With this new generation of lamps, it's very easy to obtain more grams with fewer watts. Growers using CMH will be pleasantly surprised by the amazing yield obtained thanks to them.
Disadvantages of CMH/LEC lamps
The biggest drawback of CMH lamps is that they produce short-wave UV rays that require the use of protective glasses and special clothing in order to avoid severe skin and eye burns. It's better not to stay too long in the grow room and, of course, under no circumstances should a damaged CMH lamp be used. Another major disadvantage is their high price which is indeed rather steep because there are very few models available on the market.
Manufacturers won't be able to reduce the price until demand increases. They quickly pay for themselves, though.
CMH/LEC models available on the market
The most widely used lamp so far is a 315 W CMH/LEC Philips lamp that comes with a low-frequency electronic ballast. Brands such as Lumatek and ETI are lately releasing some new models, and others are sure to follow in their footsteps and create many more lamps for indoor growing. What is clear is that CMH lamps have improved the lives of cannabis growers and we hope you can all benefit from the many advantages they offer.