315W 4200K CDM 930 Lamps are used in conjunction with suitable CDM (Ceramic discharge metal-halide) / CMH (Ceramic metal halide) fixtures, for example, the LUMII Solar 315W CDM Fixture.
The 315W 4200K CDM 930 Lamps feature a double glass jacket.
Ceramic metal halide lamps work by heating up a ceramic tube within the bulb. Ceramic can withstand much higher temperatures than other media typically used in lights. This higher temperature results in the bulb creating a plasma-like light source similar to the sun.
Since the light emitted from a CMH is akin to natural sunlight, its spectrum is closer to that of natural sunlight, so that plants exposed to CMH light are getting a wider range of wavelengths of usable light than other types of grow lights can produce.
PLEASE NOTE: On first illumination the lamp needs to be run continuously for a minimum of 15 minutes. This will allow the metals within the lamp to fuse correctly. FAILURE TO DO THIS WILL RESULT IN LAMP FAILURE!
3K Kelvin or 4K Kelvin? - Although both lamp types should be able to light a complete growing cycle with great results due to their amazing spectral outputs, traditionally growers have leaned towards higher Kelvin ratings for vegetative stages and lower Kelvin ratings for flowering stages. A 3K lamp will have a slightly yellower tint to the light it provides compared to a 4K lamp.
Why use CMH?
Best CRI color rendering index – CMH lights provide the highest measures of color rendering index (CRI) as compared to other grow lights. (Objects that are fully visible in natural, unobstructed light appear to the human eye with a CRI of 100.) Artificial lighting does not reproduce the same light as the sun, but CMH bulbs come very close, with CRI ratings ranging between a low of 80 to a high of 96.
Provides UV Lighting - CMH bulbs, as a function of offering a fuller spectrum of light, provide significantly more ultraviolet light than many other types of grow lights. Plants thrive during their vegetative stages with this type of light and it aids in the development of stronger branches. The UV-B provided by these lamps could trigger more oil and resin production in plants – a natural defense against UV light (Just like humans would put on sunscreen when out in the sun) which could provide a more terpene and trichome rich harvest! (Please use eye and even skin protection when spending longer periods under these lights)
Colour Stability - Unlike various other types of grow lights, CMH bulbs provide a consistent quality and duration of light throughout their useful life. Many types of grow lights lose effectiveness over time that may not be evident to the human eye; CMH bulbs retain their wide spectrum.
More Efficient - This is subject depending on what is being compared and for the duration that the bulb is in use, but CMH bulbs are up to 20 per cent more efficient than other types of metal halide bulbs. The yield per watt of CMH bulbs is higher.
Longer Lasting - This is another subjective benefit, but CMH bulbs do last longer than halogen and incandescent lights. They have been confirmed to run as long as 24,000 hours (almost 3 years).
Produce Less Heat - Though they operate at higher temperatures, CMH bulbs emit less heat than other types of bulbs. This is important in smaller grow rooms, where a grow light may contribute to temperatures that are too high for efficient growth and yields.
No Electromagnetic Interference - The ceramic in CMH bulbs does not interfere with electronics such as cell phones or television signals the way that some other types of grow lights or electronic ballasts can. This is not only a convenience, but helps to avoid detection if the intent of a grow room is to keep a low profile.