CDM Grow Lights
CDM (Ceramic Discharge Metal Halide) grow lights, also known as CMH, produce an intense full-spectrum light that’s closer to natural daylight than standard HPS lighting. Alongside PAR, CDM lamps emit UVA and UVB light, which many growers credit for improved crop quality, taste, aroma, and essential oil production. Watt-for-watt, CDM is more efficient than HPS — some growers report that a 315W CDM lamp can produce yields comparable to a 500W HPS setup.
Hydro Land stocks 315W CDM lamps and reflectors from Philips and Maxibright, available in 3100K for flowering and 4200K for vegetative growth, alongside standard, remote, and connect-style reflectors to suit your setup.
Shop CDM Grow Lights by Component
Lamps
Choose your 315W CDM lamp by color temperature to match your current grow stage. Our 3100K lamps deliver a warmer, red-leaning spectrum built for flowering, while our 4200K lamps produce a cooler, blue-leaning spectrum suited to vegetative growth.
Reflectors
Pair your lamp with a standard reflector shade for straightforward, all-in-one setups, or choose a Horizon Remote or Horizon Connect reflector to separate the ballast from the fixture and reduce heat directly above the canopy. Connect-style reflectors include an integrated ballast mount for a tidier, space-saving setup.
How to Choose the Right CDM Grow Light
Choosing the right CDM grow light comes down to three decisions: understanding how CDM differs from HPS, picking the correct color temperature for your grow stage, and choosing a reflector style that suits your setup. Getting these right gives you full-spectrum, high-efficiency light matched to exactly what your plants need.
What is a CDM grow light, and how does it differ from HPS?
A CDM (Ceramic Discharge Metal Halide) grow light produces full-spectrum, sunlight-like light, compared to the red-heavy output of a standard HPS lamp. This broader spectrum is why many growers choose CDM to improve crop quality, aroma, and essential oil production. Browse our CDM lamps to compare against our HPS range.
What is HID lighting, and how does CDM fit in?
HID (High Intensity Discharge) is the broader lighting category that includes both CDM and HPS grow lights. CDM sits within this group as the full-spectrum specialist, offering higher efficiency than HPS watt-for-watt.
3100K vs 4200K CDM lamps which do I need?
A 3100K CDM lamp produces a warmer, red-leaning spectrum suited to flowering, while a 4200K lamp produces a cooler, blue-leaning spectrum better suited to vegetative growth. Check our Lamps range to find the correct color temperature for your current grow stage.
Standard vs remote reflectors — which should I choose?
A standard reflector shade suits most single-tent setups, while a remote or connect-style reflector separates the ballast from the light fixture, reducing heat directly above the canopy. If heat management is a priority in your grow room, a remote reflector is worth the upgrade.
Is CDM more efficient than HPS?
Yes. CDM produces more usable light per watt than HPS, and some growers report a 315W CDM lamp yielding comparably to a 500W HPS setup making it a strong choice if you're looking to reduce running costs without sacrificing output.
Why Buy CDM Grow Lights from Hydro Land
Hydro Land supplies 315W CDM (Ceramic Discharge Metal Halide) lamps and reflectors sourced directly from Philips and Maxibright, so every lamp you buy is genuine and correctly rated for its stated color temperature. Whether you need a 3100K lamp for flowering or a 4200K lamp for vegetative growth, our range is specified clearly so you can match the right lamp to your grow stage without guesswork.
If you're upgrading from HPS, our technical support team can help confirm whether your existing ballast is CDM/CMH-compatible before you order, avoiding a mismatch between lamp and ballast. Every order is dispatched quickly from the UK, backed by a team with genuine working knowledge of HID lighting systems — not just a product catalogue.
Frequently Asked Questions
What does CDM stand for in grow lighting?
CDM stands for Ceramic Discharge Metal Halide, also known as CMH. It's a type of HID grow light that produces full-spectrum, sunlight-like light for indoor growing.
What's the difference between 3100K and 4200K CDM lamps?
3100K CDM lamps produce a warmer, red-leaning spectrum suited to flowering. 4200K CDM lamps produce a cooler, blue-leaning spectrum better suited to vegetative growth.
Is CDM more efficient than HPS?
Yes. CDM produces more usable light per watt than HPS, and some growers report a 315W CDM lamp yielding comparably to a 500W HPS setup.
Can I use a CDM lamp with my existing HPS ballast?
Only if the ballast is rated for CDM/CMH lamps. Standard HPS ballasts aren't always compatible, so check your ballast's specification before switching lamp types.