CMH & LEC Grow Lights -- 315W, 630W & 1000W
Ceramic metal halide (CMH) and light emitting ceramic (LEC) grow lights produce a broad, full-spectrum output that more closely mimics natural sunlight than standard HPS or MH sources -- including UV and far-red wavelengths that are largely absent from HPS. The ceramic arc tube in CMH/LEC lamps runs at lower operating temperatures than quartz HPS, producing a color rendering index (CRI) above 90 and a spectral distribution that supports more complete plant photosynthesis and secondary metabolite production. The 315W and 630W double-ended CMH configurations are the most widely adopted formats; 1000W DE MH systems are used in large commercial canopy applications.
315W, 630W, and 1000W Configurations
The 315W single-lamp CMH fixture covers a 3x3 to 4x4 canopy effectively in vegetative and early flowering stages. The 630W double-ended CMH uses two 315W lamps in a DE reflector, covering a 4x4 to 5x5 footprint at full flowering intensity. For large-canopy commercial applications, the 1000W DE MH format provides maximum output per fixture position. Iluminar, Growers Choice, NanoLux, and DimLux are the qualified CMH brands at Hydrobuilder, each offering complete fixture and bulb combinations at 315W and 630W. Browse replacement CMH bulbs in 3000K, 3100K, and 4200K color temperatures, or see LED grow lights for a comparison. Expert support available.
CMH vs. LED for Commercial Growing
CMH/LEC remains a competitive choice for commercial growers who value its proven spectral quality, lower upfront fixture cost compared to premium LEDs, and the ability to replace bulbs rather than entire fixtures at end of service life. LED fixtures have surpassed CMH in energy efficiency at comparable output levels, but CMH continues to be widely used in commercial production where the full-spectrum output and UV component justify the operating costs. For operations evaluating a CMH-to-LED transition, call 888-815-9763 to discuss the numbers for your specific facility.
CMH & LEC Grow Lights FAQ
What is the difference between CMH and LEC grow lights?
CMH (ceramic metal halide) and LEC (light emitting ceramic) refer to the same lamp technology -- both use a ceramic arc tube rather than the quartz glass used in standard MH lamps. LEC is a trademarked term used by Sun System/Hortilux; CMH is the generic industry term for the same technology. Both produce a broad-spectrum, high-CRI output with UV and far-red components not found in standard HPS or quartz MH sources. For practical purchasing purposes, CMH and LEC fixtures and bulbs from different manufacturers are functionally equivalent, though bulbs from one manufacturer may not be compatible with another's ballast -- verify compatibility before purchasing replacement bulbs.
What canopy size does a 630W CMH cover?
A 630W double-ended CMH fixture effectively covers a 4x4 to 5x5 foot canopy at flowering-level intensity. At 4x4, a 630W CMH delivers strong PPFD output across the entire footprint. At 5x5, light uniformity drops toward the canopy edges -- acceptable for vegetative stages or for strains that tolerate moderate light variation, but a second fixture is typically added for maximum-yield commercial flowering in 5x5 zones. The 315W single-lamp CMH covers 3x3 to 4x4 at appropriate intensity levels for both vegetative and flowering stages.
How often should CMH bulbs be replaced?
CMH/LEC bulbs should be replaced annually in commercial production environments running 12-18 hours per day. Bulb lumen output degrades over time even as the lamp continues to fire -- a 12-month-old bulb operating at 80% of its original output means your plants are receiving significantly less light than your fixture is rated for. In hobby setups running shorter daily cycles, bulb life can extend to 18-24 months before replacement is warranted. Track run-hours rather than calendar time for the most accurate replacement schedule. Replacement 315W and 630W CMH bulbs are available in 3000K, 3100K, and 4200K color temperatures at Hydrobuilder.
