SKU: 34404636431
cmh grow light bulb

cmh grow light bulb Growers Choice Horticultural Lighting 315W SE CMH Complete Fixture 3K

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Description

cmh grow light bulb Growers Choice Horticultural Lighting 315W SE CMH Complete Fixture 3KGrower's Choice 315W CMH Grow Light Happy Hydro Full spectrum light that actually matches sunlight, at 315 watts The Grower's Choice GC 315 is a complete ceramic metal halide fixture with a built in digital ballast, open reflector, and your choice of lamp spectrum. CMH produces a broader, more balanced spectrum than HPS with a CRI up to 97, which means your plants see light closer to what they'd get outdoors. The fixture runs 120V 240V, dims without

Grower's Choice 315W CMH Grow Light | Happy Hydro

Full-spectrum light that actually matches sunlight, at 315 watts

The Grower's Choice GC-315 is a complete ceramic metal halide fixture with a built-in digital ballast, open reflector, and your choice of lamp spectrum. CMH produces a broader, more balanced spectrum than HPS with a CRI up to 97, which means your plants see light closer to what they'd get outdoors. The fixture runs 120V/240V, dims without external controllers, and includes full circuit protection so you're not replacing ballasts after a power surge.

3-year warranty 120V/240V compatible Controller compatible
Free shipping on orders over $49
30-day returns on all orders
Serving growers since 2006
Side by side
315W CMH vs. a standard 600W HPS
600W HPS
  • Narrow spectrum, heavy in yellow/orange, almost no UV or blue
  • 600W draw plus additional cooling costs
  • Separate ballast, reflector, socket, and lamp to assemble
  • Magnetic ballasts hum, flicker, and lose efficiency over time
  • Bulbs degrade quickly, typically need replacement every 6 to 9 months
  • No built-in dimming or fault protection
GC-315 CMH
  • Full spectrum with UV, blue, red, and far-red, CRI up to 97
  • 315W draw, nearly half the power for competitive PAR output
  • All-in-one fixture: ballast, reflector, and lamp in one unit
  • Digital square-wave ballast, no hum, no flicker, consistent output
  • 15,000-hour rated lamp life, roughly double a standard HPS bulb
  • Built-in dimming dial and full circuit protection against surges
What makes it different
Built for real grow rooms, not spec sheets

Closest spectrum to sunlight available in HID CRI up to 97

The 4K lamp scores a 97 CRI, meaning its spectral output is nearly identical to natural daylight. The 3K lamp sits at CRI 90 with enhanced red for flowering. Plants respond to this broader spectrum with tighter internodal spacing and more uniform growth.

Low-frequency square wave ballast

The digital ballast drives the lamp with a low-frequency square wave, which is up to 30% more efficient than magnetic ballasts and maintains that efficiency for the life of the unit. No internal fans needed because the case design acts as a passive heat sink.

Full circuit protection with 3-second self-test

On every ignition, the ballast runs a 3-second diagnostic. It protects against open circuit, short circuit, over-voltage, under-voltage, and over-temperature faults. If something is wrong, the ballast enters protection mode instead of damaging itself or the lamp.

Dimmable with Smart Step and Super Lumen modes

Turn the dial to reduce output when plants are young or temperatures are high. Super Lumen pushes the lamp past rated wattage for maximum PAR when you need peak intensity during late flower.

Runs cooler than HPS at comparable PAR

At 315W, this fixture produces significantly less radiant heat than a 600W HPS. In small tents or rooms without dedicated HVAC, that can be the difference between manageable temperatures and constant heat stress.

Compatible with Grower's Choice Master Controller

Daisy-chain up to 100 fixtures per zone using the optional Master Lighting Controller. Supports timed on/off, sunrise/sunset ramping, and dual thermal probe auto-dim shutdown for commercial setups.

Specs
Technical specifications
Wattage
315W
Input voltage
120V / 240V (50/60 Hz)
PAR output (3K lamp)
570 µmol/s initial
Coverage area
3' x 3' flower, 3.5' x 3.5' veg
Lamp life
15,000 hours rated
Input current
2.9A @ 120V, 1.5A @ 240V
Power factor
> 0.98
Warranty
3 years (Grower's Choice)

Setting up your GC-315

1

Hang the fixture

Use the included hanging hardware to mount the fixture from your tent crossbars or ceiling hooks. Adjust height to 18 to 24 inches above the canopy for flowering, 24 to 30 inches for veg.

2

Install the lamp

Insert the 315W CMH lamp into the built-in socket. The lamp seats horizontally in the open reflector. Handle by the base only, not the glass envelope.

3

Set the power level

Turn the ballast dial to your preferred output. Start lower for seedlings or clones, then step up to full power as plants mature. Use Super Lumen mode during peak flower if temperatures allow.

4

Plug in and grow

Connect to any standard 120V outlet (ships with a 120V plug). For 240V operation, swap the cord end or hardwire. The ballast auto-detects frequency and adjusts output to prevent flicker.

In the box
Everything you need to start growing
Included with every fixture
  • GC-315W all-in-one fixture with integrated digital ballast
  • One 315W CMH lamp (your choice of spectrum)
  • Open reflector with horizontal lamp mount
  • 120V power cord (pre-attached)
  • Hanging hardware
  • 3-year manufacturer warranty
Lamp options
  • 3K-R (3,100K): Full spectrum optimized for bloom, enhanced red, CRI 90, 570 µmol/s
  • 4K (4,200K): Veg-optimized with heavy blue output, CRI 97, promotes tight internodal spacing
  • 10K MH Finishing: Metal halide finishing lamp for the final 2 weeks, boosts resin and aroma
  • No Bulb: Fixture only, bring your own 315W SE CMH lamp
Not sure which lamp to pick? The 3K-R is the most popular choice for growers who want one lamp for the full cycle. If you run separate veg and flower spaces, pair the 4K for veg with the 3K-R for flower. Call or email us: 716-217-0353 / [email protected]
Questions
Frequently asked questions
The GC-315 flowers a 3x3 area effectively and vegs a 3.5x3.5 area. In a 4x4 tent, you'll get solid growth in the center but the corners will be noticeably dimmer. For full 4x4 coverage in flower, most growers either run two 315W fixtures or step up to a 630W CMH or LED. If you're growing one or two large plants in the center of a 4x4, a single 315W can work fine.
LEDs in this price range typically pull similar wattage but produce a narrower, diode-driven spectrum. CMH's advantage is spectral quality: the broad, continuous spectrum is closer to sunlight than the peaked spectrum of most LEDs. Many growers report visibly healthier plants and tighter structure under CMH compared to budget LEDs. The trade-off is that CMH generates more heat and the lamp needs replacement every 15,000 hours. If heat is your main concern, LED may be the better fit. If spectrum quality matters more, CMH wins at this price.
Grower's Choice rates their CMH lamps at 15,000 hours. Running 18 hours per day in veg, that is roughly 2.3 years. Running 12 hours per day in flower, that is about 3.4 years. Spectrum and output do degrade over time, so many growers swap lamps every 12 to 18 months for peak performance. Replacement lamps are available separately on our site.
The ballast accepts both 120V and 240V input. It ships with a 120V plug. To run on 240V, you'll need to swap the plug or hardwire to a 240V circuit. Running on 240V draws less current (1.5A vs 2.9A), which is better if you're running multiple fixtures on the same breaker. The fixture auto-adjusts, no switch or setting needed.
Yes, any standard single-ended 315W CMH lamp with a PGZ18 base will fit. Grower's Choice lamps are optimized for this ballast's frequency and output, so using their lamps ensures the best spectral performance and longest lamp life. Third-party lamps will work but may not perform identically.
Not for a single fixture. A standard appliance timer handles on/off scheduling, and the built-in dial controls dimming. The optional Grower's Choice Master Lighting Controller becomes useful when you're running multiple fixtures and want centralized sunrise/sunset ramping, thermal monitoring, and auto-dim shutdown. We carry the controller separately if you need it later.
If you receive a defective or damaged unit, email us a photo at [email protected] and we'll make it right immediately: replacement or refund, your call. For change-of-mind returns, we accept returns within 30 days for items in new, resalable condition. If you're not sure whether this product is right for your setup, call us first at 716-217-0353. We'd rather answer your questions before you order.
Happy Hydro has been selling growing equipment since 2006. We've carried Grower's Choice for years because the systems work great and customers who buy them leave happy. Have questions before you order? Call 716-217-0353 or email [email protected]. We're easy to reach and happy to help!
Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 34404636431

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Reviewed in the United States on January 16, 2026
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Living in an older home often means dealing with outdated two-prong outlets and a frustrating lack of convenient charging options. This 2-prong extension cord and outlet adapter solves that problem beautifully by converting a polarized two-prong outlet into an incredibly versatile charging station with 11 AC outlets and 6 USB ports. 🏠✨📱 I have been using this type of power strip in areas where only older two-prong outlets are available, and it makes a tremendous difference. Instead of relying on multiple adapters and extension cords, everything can be plugged into one compact unit. 🔌💻📺 Whether charging phones, tablets, laptops, lamps, and other electronics, this power strip keeps everything organized and easy to access. The standout feature is the impressive 17-in-1 design. With 11 AC outlets and 6 USB ports, including 3 USB-C ports, it can power and charge a large number of devices simultaneously. 📱💻⌚🎮 The USB-C ports provide fast charging for many modern devices, which reduces the need for separate charging bricks and helps minimize clutter. I especially appreciate the thoughtful outlet layout. The three-row design provides generous spacing so larger power adapters do not block neighboring outlets. 🧠🔌👌 This makes it easy to use nearly every outlet at once, which is extremely useful for office setups, entertainment centers, and bedside charging stations. The five-foot extension cord offers excellent flexibility, and the flat angled plug fits neatly behind furniture without protruding too far from the wall. 🛋️📏✨ This is particularly helpful in tight spaces such as behind bookcases, sofas, and nightstands. The built-in mounting holes are another nice touch, allowing the unit to be securely attached to a wall or desk if desired. Safety features are also reassuring. With surge protection, overload protection, short-circuit protection, and fire-resistant construction, this power strip is designed to handle daily use with confidence. 🛡️⚡🔥 Knowing that connected electronics are protected adds significant peace of mind. For anyone living in an older house with two-prong outlets, this adapter offers a practical and highly efficient solution. It instantly modernizes outdated electrical access and provides abundant outlets and charging ports in one organized unit. 🏡🔌📱 Overall, this is an exceptionally useful power strip that combines convenience, charging versatility, and robust safety features. With 11 outlets, 6 USB ports, fast USB-C charging, and compatibility with older two-prong outlets, it is an excellent addition to any home, office, dorm room, or gaming setup. ⚡🏡🔌💻📱✨
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