SKU: 97629230116
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: 97629230116

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mrcricket
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★★★★★ 3
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Item is as described however this one appeared to be open and some parts possibly used. Example pole packaging mislabeled one had the letter K as a part there is no letter K item in the instructions. Another pole part had a taped on letter A which is completely different from the others thus indicating that it was opened or substituted. Finally after the partition was completely put together one of the bottom screw connection anchors came out making the partition unable to stand. I'm going to have to rig something up in order to get the anchor connected to the bottom panel. In closure the partion could be very acceptable and do the job if it was new and parts labeled correctly. I have pictures of all parts and packaging errors. Would buy again if new. I'm going to pursue some kind of compensation.
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Reviewed in the United States on March 15, 2026
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Wendy Gray
Alexandria, US
★★★★★ 5
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Color: Grey, Size: 34"- 6 Panel
This room divider is great. It was easy to put together. I was worried about it standing up right and not falling over. It stays up perfectly and is very easy to move and adjust to the shape I want it. Also, from one of the videos I watched it looked like the fabric was puckered in the panels. That is not the case at all. The fabric fits tightly in each panel for a nice smooth look. I would definitely recommend this and would buy again if needed.
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Reviewed in the United States on March 3, 2025
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Alex caine
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Awful.
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Easiest one star review ever. I'm writing this with bloody fingers from assembling this. Multiple poles were bent, none of the pole connectors worked, the hex wrench broke in my hand, the screws didn't really go into the holes provided (I had to get a friend with a press drill to widen the holes to make it work), there are sharp edges on the poles where there is a seam, and doesn't look that great once assembled. Easy do not buy, the only reason I didn't return is because it would have been tough to disassemble the half I got through in the first 5 hours of building (mostly spent fixing the product delivered)
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Reviewed in the United States on December 30, 2025
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Kevin
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Matter-enabled High Quality Light Strips
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Great lights. Used these as accent lights behind an entertainment center to avoid harsh overhead lights. Three in total. They put out plenty of light and easy to install and use. Love the Matter integration. Negatives: can’t use the cut portion. Once it’s cut, the extra is useless. Not cheap for a light strip. Purchase if you like the light tech or want Matter integration. You have to guess for “light temperatures” (warm, daylight, etc.). I used a Google search for finding the Hex # to input into light control and fine tune from there Love these and would buy again
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Reviewed in the United States on March 18, 2026
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S.
Battle Creek, US
★★★★★ 5
Great product, reliable quality!
Size: 9.8ft, Size: 9.8ft
I moved into a new place with wood stairs. There’s a landing step that is invisible at night - it just looks like the floor below the step. Of course, one can only determine a stair to be invisible at night after one misses said stair, falling, twisting ankle and foot, lying on floor cursing and crying for help from the husband at 11pm in the dark. I used painters tape for a couple of weeks. Again, not so helpful at night but there was some distinction. I knew I needed to light this step up to avoid future slips on the invisible step. I love Govee products. I have a Govee metal tall skinny lamp thing which is where I learned about this gummy, straight, light tube that they make. I really did not want the light strips that were cheaper w the separate little lights on them since this was going under a stair and you could see the underside of the stair clearly from our lower living room whilst sitting on the couch. This product was SUPER easy to install. I love that you can cut it to size (though if you need exact I would go with the Govee light strips w the little lights there’s more cut areas closer together). I love that I already have the Govee app and it connected relatively easily (turning things on/off, using airplane mode and unplugging will get you connected). My 2 gripes about Govee… 1. Please figure out how to make strips that you can cut and connect - I want to be able to configure a corner or different shape besides just a straight line. I also want to be able to connect multiple lines to one adapter (I had a cheap one that could do this but I was afraid it would burn my house down). I paid $$$ for a single step and would like to have been able to use the rest of my strip for another step but instead it’s just useless. 2. I wish it dimmed a little more - the 1% is really bright in the dark. This strip is VERY bright. Anyways, love my step and it’s safe to take the painters tape off and have it be a normal step.
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Reviewed in the United States on April 8, 2026

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