Choosing the right grow lights is an important part of setting up your grow tent or grow room. Maybe you’ve narrowed your options down to HID grow lights, but after that, there are even more choices to make!
HIDs include HPS grow lights and CMH grow lights, which differ in a few ways that can give you significantly different results in your grow room.
Don’t worry about making the wrong choice, though. We’ve laid out the differences between the two types of grow lights, along with the pros and cons of each. That way you can figure out exactly which grow light will be the best option for your grow room without any hassle.
Table of Contents
What’s the Difference Between HPS and CMH Grow Lights?- Power of HPS Grow Lights vs. CMH Grow Lights
- Advantages of HPS Grow Lights
- Advantages of CMH Grow Lights
- HPS vs. CMH Grow Lights: The Final Verdict
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Best HPS and CMH Lights
- Strongest HPS Grow Light: Yield Lab Professional Series 1000W HPS Open Wing Double Ended Reflector
- Strongest CMH Grow Light: Yield Lab Professional Series 120/220v 630w Dual Bulb CMH Complete Grow Light Kit
- Most Versatile 600w Light: Yield Lab 600w HPS Air Cool Tube Digital Dimming Grow Light Kit
- The Best HPS Grow Light for 1 to 2 Plants: Yield Lab 400w HPS Air Cool Hood Grow Light Kit
- The Best CMH Light for Compact Spaces: Yield Lab Professional Series 120/220v 315w All-In-One Hood CMH Complete Grow Light Kit
- Choosing the Best HPS and CMH Lights for Your Grow Room
Alright, let’s dive deep into HPS grow lights and CMH grow lights so you can make the best decision for your grow room.
What’s the Difference Between HPS and CMH Grow Lights?
To figure out which one of these lights will work best in your grow room, you’ll first need to understand the key differences between the two. HPS and CMH lights are both the same type of grow light: they’re HID, or High Intensity Discharge lights.
HPS and CMH lights are simply different types of grow bulbs. The main difference between them is the chemical makeup within the bases of the bulbs. Because these bulbs contain different chemicals, they give off different spectrums of light — this is the key difference you’ll want to keep in mind when choosing between the two.
- When the filament of an HPS bulb is heated, it gives off a red/orange glow. This makes it ideal for all stages of a plant’s growth, but it’s especially great for the flowering stage.
- On the other hand, when the filament of a CMH bulb, which has a ceramic base, heats up, it gives off a piercing blue glow. This blue spectrum is closer to a full spectrum of light than the red/orange of the HPS bulb. A CMH bulb’s spectrum is suitable for all stages of growth, but it’s especially effective during the vegetative cycle.
Intensity of HPS Grow Lights vs. CMH Grow Lights
Intensity is an important factor to consider when choosing grow lights for your garden. The more lumens a bulb gives off, the brighter and intense that light will be, which translates into stronger plant growth. However, the stronger the light, the more power it'll take to run it.
There are power and intensity limits to each style of light. So in this section we'll discuss the differences in intensity between HPS and CMH lights, diving into the power capabilities of each.
HPS Grow Lights
- Power Options: HPS grow lights are generally available at 3 different wattages: 400w, 600w, and 1000w.
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HPS Lumen Output: In general, 400w HPS bulbs gives off 55,000 lumens, a 600w HPS bulb offers more than 90,000 lumens, and 1000w HPS bulbs 130,000 lumens.
- Note: Double ended HPS options can offer even higher lumen outputs. 600w's sit around 96,600 lumens, and 1000w double ended HPS bulbs start around 159,200 lumens.
- HPS Color Temperature and Light Spectrum — The standard HPS grow light's color temperature is 2100k. This color temperature offers an orange, warm light spectrum that's especially helpful in the flowering stage of growth.
- Overall Review — Though HPS lights may not have the widest spectrum, they offer huge potential for power and light intensity.
Now let's take a look at what CMHs have to offer.
- CMH Grow Light Wattage — CMH bulbs come in 1 wattage: 315w. However, some CMH lights use 2 CMH bulbs in one reflector and usea total wattage of 630w.
- CMH Lumen Output — A single 315w CMH bulb gives off 36,000. As such, 2 CMH bulbs would give off 72,000 lumens.
- CMH Color Temperature and Light Spectrum — 315w CMH bulbs come in both 3100k (flowering spectrums) and 4200k (vegging spectrums). That means you can use two types of bulbs to target various spectrums of light for different phases of growth.
- Overall Review — Although CMH grow lights may be less powerful than HPS bulbs, they offer more variety of spectrums, giving you both flowering and vegging spectrums.
Advantages of HPS Grow Lights
We’ve already noted one of the biggest advantages of HPS grow lights, which is their potential for power. Let’s dive a little deeper into the lumen output, light intensity, and other advantages of HPS grow lights.
- High Lumen Output — A 1000w HPS bulb gives you 130,000 lumens in a single light! Meanwhile, the highest amount of lumens CMH lights can offer you is 72,000 to 75,000 — and that’s with 2 bulbs. That means a single HPS bulb is 3 times more powerful than a CMH bulb.
- Multiple Reflector Options — HPS grow lights offer a wide variety of reflectors that can be tailored to fit all of your growing needs. There are single or double ended wing reflectors, air cool hood reflectors, air cool tube reflectors, and umbrella reflectors. CMH lights are limited in that department as there are only a handful of CMH reflectors available.
- Single and Double Ended Options — With HPS grow lights, you can choose between a single ended bulb or double ended bulb, while CMH bulbs are only available as single ended lights. Double ended grow lights are a major advantage because they can add at least 5,000 lumens on top of a single bulb. That can really maximize the power.
- HPS Grow Lights Are More Affordable — HPS grow lights also win in the price department. The Yield Lab 400w HPS Cool Tube Reflector Digital Grow Light Kit goes for $174.95. This is significantly less than the Yield Lab Professional Series 120/220v 315w All-In-One Hood CMH, priced $65 higher at $239.95. The HPS kit is an especially great deal when you consider the fact that it offers 19,000 more lumens than the CMH kit. It’s all around more bang for your buck.
Advantages of CMH Grow Lights
Though HPS lights may be great for any grow room, don’t count out CMH grow lights just yet. HPS grow lights may be more affordable and more powerful, but CMHs definitely have their benefits, too.
- Wider, Even Light Spectrum — Like we touched on before, CMH grow lights will give you a much wider and more even spectrum of light than HPS lights will. That means better coverage with more light that your plants can use.
- Higher Color Temperature — The higher color temperature of a CMHs allows them to give off a great amount of blue, red, and white light, which makes them beneficial throughout the entire life of your plant. Meanwhile, HPS bulbs offer a more limited spectrum range. This can affect your plants during their vegging stage, when they'll need a bit more than HPS lights can offer — including UV light, which boosts flavors and aromas.
- CMHs Run Cooler than HPS Lights — Another benefit of CMH lights over HPS bulbs is that they produce less heat. This makes sense, considering the fact that they generate less lumens. Even a 630w CMH light will run cooler than a 600w HPS bulb. So while HPS lights are cheaper overall, CMH lights will definitely save you some cooling costs during those hot summer months.
HPS vs. CMH Grow Lights: The Final Verdict
Both HPS and CMH lights are probably looking pretty good to you right now. If that's the case, you might be wondering which is the better option considering they both offer some impressive advantages.
At the end of the day, both HPS grow lights and CMH grow lights are good options for your grow room. The right choice for your plants and your grow room goals ultimately depends on what you’re looking for:
- If you want more power, go with HPS grow lights! They outrank CMH lights by a landslide when it comes to lumen output.
- That said, if you want a more even spectrum of light, CMH grow lights are the right option for you. They’ll most accurately mimic the light of the sun in order to provide the proper spectrums for your plants at each stage of growth.
Best HPS and CMH Lights
Even if you know which type of light you want, there are still lots of options for both HPS and CMH grow lights! We’ve put together a list of the best ones out there for you, ranked by category. That way you can find the perfect light for your grow.
Strongest HPS Grow Light: Yield Lab Professional Series 1000W HPS Open Wing Double Ended Reflector
If you’re looking to get the most strength out of your grow lights, you’re probably going to go with HPS lights. The Yield Lab Professional Series 1000W HPS Open Wing Double Ended Reflector kit is the best of the best when it comes to lumen output!
The bulb offers 159,200 super-charged lumens. This grow light kit is the way to go if you want to get your plants as huge as possible. This grow light will provide large amounts of light intensity to your plants so that they can convert nutrients into heavy doses of usable energy.
In addition, though HPS lights are known for releasing high levels of heat, the open wing design of this grow light kit allows for an even spread of light. This means the heat it generates isn’t as focused, which means a cooler-running HPS light.
The open style of this grow light is what truly sets it apart from other units. Aside from lower heat levels, it also provides wide coverage so that all the plants in your grow room get great light intensity.
HPS Grow Light Specs:
- Wattage: 1000w
- Lumen output: 159,200
- Color temperature: 2100k
Our Price: $279.95 | Click Here to Buy This HPS Grow Light
Strongest CMH Grow Light: Yield Lab Professional Series 120/220v 630w Dual Bulb CMH Complete Grow Light Kit
If you’re going with CMH bulbs in order to get a good, even light spectrum for your grow room, you’ll want to get as much power as possible out of your light. While no CMH light will be as strong as HPS lights, they can still offer a good amount of power. The Yield Lab Professional Series 120/220v 630w Dual Bulb CMH Complete Grow Light Kit is your strongest option.
This CMH grow light kit will give you 72,000 lumens of usable light, making it easy for at least 3 to 4 plants to thrive off of it. This light also gives off UV rays and a 3100k color temperature. This is in stark contrast to HPS bulbs, which will only be able to give you a limited spectrum and 2100k.
Speaking of which, though it’s not as powerful as an HPS, the design of this CMH grow light hood allows for focused light to hit all your plants. That’s why it’s the most powerful CMH light kit available.
So if you want to get the advantages of a wide spectrum of light, while still getting solid intensity, this CMH grow light is the way to go.
CMH Grow Light Specs:
- Wattage: 630w (315w x 2 bulbs)
- Lumen output: 72,000
- Color temperature: 3100k
Our Price: $389.95 | Click Here to Buy This CMH Grow Light
Most Versatile 600w Light: Yield Lab 600w HPS Air Cool Tube Digital Dimming Grow Light Kit
If you’re looking for versatility in your grow lights, check out the Yield Lab 600w HPS Air Cool Tube Digital Dimming Grow Light Kit. The cool tube is thin enough to fit into smaller growing areas like 2x4ft grow tents, but the light’s lumen output is also super strong.
Despite this grow light kit’s compact size, it packs a punch with 90,000 lumens. That’s enough for at least 3 plants.
The HPS light kit’s tubular shape makes it especially versatile, as it can be used in vertical grows for plants that are growing in a tower or against a wall. Overall, it offers lots of room for adjustment and can work in virtually any grow room.
HPS Grow Light Specs:
- Wattage: 600w
- Lumen output: 90,000
- Color temperature: 2100k
Our Price: $179.95 | Click Here to Buy This HPS Grow Light
The Best HPS Grow Light for 1 to 2 Plants: Yield Lab 400w HPS Air Cool Hood Grow Light Kit
If you have a small grow room and just need to care for a few plants, the Yield Lab 400w HPS Air Cool Hood Grow Light Kit is a great option to consider. The cool hood included helps focus intense light onto your plants within a small 3x3ft growing area, which is perfect for a smaller grow tent or grow room.
Offering 55,000 lumens in this tight space, this HPS grow light is perfect for 1 to 2 plants. You’ll get a lot of light intensity for the wattage — so if you’re just looking to get into growing, or you simply want to keep your grow small, you won’t find a better option.
In addition, at just $174.95, this is one of the most affordable grow light kits around. Plus, do to its lower wattage, you’ll also keep your electric bill from increasing too much.
HPS Grow Light Specs:
- Wattage: 400w
- Lumen output: 55,000
- Color temperature: 2100k
Our Price: $174.95 | Click Here to Buy This HPS Grow Light
The Best CMH Light for Compact Spaces: Yield Lab Professional Series 120/220v 315w All-In-One Hood CMH Complete Grow Light Kit
If you want to go the CMH route for your small grow space, the Yield Lab Professional Series 120/220v 315w All-In-One Hood CMH Complete Grow Light Kit is the ideal choice. It can provide the perfect amount of light for 2 to 3 plants, offering 36,000 lumens.
While it’s not quite as powerful as the HPS grow light option listed above, it makes up for its lower power with an even color spectrum and UV rays. This means you’ll see some high-quality harvests, thanks to the fact that the light provides ideal spectrums for each stage of growth.
If you’ve got a small grow space and want your plants to get the most varied spectrum of light, this CMH grow light kit is the best option for the job.
CMH Grow Light Specs:
- Wattage: 315w
- Lumen output: 36,000
- Color temperature: 3100k
Our Price: $239.95 | Click Here to Buy This CMH Grow Light
Choosing the Best HPS and CMH Lights for Your Grow Room
Regardless of your grow space, plants, and goals you may have for your grow room, there’s a grow light that can meet your needs! HPS and CMH grow lights are great for any grow room or grow tent operation.
Just remember that if power is your number one priority, you should choose an HPS grow light. With an HPS, you’ll get a lot of light intensity for your plants.
If, however, you’re looking to get the best spectrum for your plants, definitely go with one of the CMH options. Due to how CMH grow lights mimic sunlight more accurately, they’re able to provide a broader spectrum of light for your plants.
Once you figure out the perfect grow light for your specific needs, you’ll be well on your way to the grow room of your dreams.